diff options
| author |  Mark D. Roth <roth@google.com> | 2018-12-20 10:10:19 -0800 |
|---|---|---|
| committer | Mark D. Roth <roth@google.com> | 2018-12-20 10:10:19 -0800 |
| commit | 09f57c17ee22e344adad9d81be5747305a02d33e (patch) | |
| tree | 116d22f6ea59a4e9e1d28981e6dc9720589fb804 | |
| parent | b96196f65586ea5832325314adb6f90df07aec51 (diff) | |
Refactor request routing code out of client_channel.
24 files changed, 1361 insertions, 906 deletions
@@ -1056,6 +1056,7 @@ grpc_cc_library( "src/core/ext/filters/client_channel/parse_address.cc", "src/core/ext/filters/client_channel/proxy_mapper.cc", "src/core/ext/filters/client_channel/proxy_mapper_registry.cc", + "src/core/ext/filters/client_channel/request_routing.cc", "src/core/ext/filters/client_channel/resolver.cc", "src/core/ext/filters/client_channel/resolver_registry.cc", "src/core/ext/filters/client_channel/resolver_result_parsing.cc", @@ -1079,6 +1080,7 @@ grpc_cc_library( "src/core/ext/filters/client_channel/parse_address.h", "src/core/ext/filters/client_channel/proxy_mapper.h", "src/core/ext/filters/client_channel/proxy_mapper_registry.h", + "src/core/ext/filters/client_channel/request_routing.h", "src/core/ext/filters/client_channel/resolver.h", "src/core/ext/filters/client_channel/resolver_factory.h", "src/core/ext/filters/client_channel/resolver_registry.h", diff --git a/CMakeLists.txt b/CMakeLists.txt index 1f34bf841d..7688630781 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -1210,6 +1210,7 @@ add_library(grpc src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -1562,6 +1563,7 @@ add_library(grpc_cronet src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -1935,6 +1937,7 @@ add_library(grpc_test_util src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -2256,6 +2259,7 @@ add_library(grpc_test_util_unsecure src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -2589,6 +2593,7 @@ add_library(grpc_unsecure src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -3443,6 +3448,7 @@ add_library(grpc++_cronet src/core/ext/filters/client_channel/parse_address.cc src/core/ext/filters/client_channel/proxy_mapper.cc src/core/ext/filters/client_channel/proxy_mapper_registry.cc + src/core/ext/filters/client_channel/request_routing.cc src/core/ext/filters/client_channel/resolver.cc src/core/ext/filters/client_channel/resolver_registry.cc src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -3723,6 +3723,7 @@ LIBGRPC_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ @@ -4069,6 +4070,7 @@ LIBGRPC_CRONET_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ @@ -4435,6 +4437,7 @@ LIBGRPC_TEST_UTIL_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ @@ -4743,6 +4746,7 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ @@ -5050,6 +5054,7 @@ LIBGRPC_UNSECURE_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ @@ -5881,6 +5886,7 @@ LIBGRPC++_CRONET_SRC = \ src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ diff --git a/build.yaml b/build.yaml index 830123110a..9d73e31b2e 100644 --- a/build.yaml +++ b/build.yaml @@ -584,6 +584,7 @@ filegroups: - src/core/ext/filters/client_channel/parse_address.h - src/core/ext/filters/client_channel/proxy_mapper.h - src/core/ext/filters/client_channel/proxy_mapper_registry.h + - src/core/ext/filters/client_channel/request_routing.h - src/core/ext/filters/client_channel/resolver.h - src/core/ext/filters/client_channel/resolver_factory.h - src/core/ext/filters/client_channel/resolver_registry.h @@ -608,6 +609,7 @@ filegroups: - src/core/ext/filters/client_channel/parse_address.cc - src/core/ext/filters/client_channel/proxy_mapper.cc - src/core/ext/filters/client_channel/proxy_mapper_registry.cc + - src/core/ext/filters/client_channel/request_routing.cc - src/core/ext/filters/client_channel/resolver.cc - src/core/ext/filters/client_channel/resolver_registry.cc - src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -352,6 +352,7 @@ if test "$PHP_GRPC" != "no"; then src/core/ext/filters/client_channel/parse_address.cc \ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ + src/core/ext/filters/client_channel/request_routing.cc \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver_registry.cc \ src/core/ext/filters/client_channel/resolver_result_parsing.cc \ diff --git a/config.w32 b/config.w32 index be10faab9c..b6e71dd09a 100644 --- a/config.w32 +++ b/config.w32 @@ -327,6 +327,7 @@ if (PHP_GRPC != "no") { "src\\core\\ext\\filters\\client_channel\\parse_address.cc " + "src\\core\\ext\\filters\\client_channel\\proxy_mapper.cc " + "src\\core\\ext\\filters\\client_channel\\proxy_mapper_registry.cc " + + "src\\core\\ext\\filters\\client_channel\\request_routing.cc " + "src\\core\\ext\\filters\\client_channel\\resolver.cc " + "src\\core\\ext\\filters\\client_channel\\resolver_registry.cc " + "src\\core\\ext\\filters\\client_channel\\resolver_result_parsing.cc " + diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec index f918fe8ad9..29a79dd47a 100644 --- a/gRPC-C++.podspec +++ b/gRPC-C++.podspec @@ -355,6 +355,7 @@ Pod::Spec.new do |s| 'src/core/ext/filters/client_channel/parse_address.h', 'src/core/ext/filters/client_channel/proxy_mapper.h', 'src/core/ext/filters/client_channel/proxy_mapper_registry.h', + 'src/core/ext/filters/client_channel/request_routing.h', 'src/core/ext/filters/client_channel/resolver.h', 'src/core/ext/filters/client_channel/resolver_factory.h', 'src/core/ext/filters/client_channel/resolver_registry.h', diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec index 0a78733f8d..f873bc693b 100644 --- a/gRPC-Core.podspec +++ b/gRPC-Core.podspec @@ -349,6 +349,7 @@ Pod::Spec.new do |s| 'src/core/ext/filters/client_channel/parse_address.h', 'src/core/ext/filters/client_channel/proxy_mapper.h', 'src/core/ext/filters/client_channel/proxy_mapper_registry.h', + 'src/core/ext/filters/client_channel/request_routing.h', 'src/core/ext/filters/client_channel/resolver.h', 'src/core/ext/filters/client_channel/resolver_factory.h', 'src/core/ext/filters/client_channel/resolver_registry.h', @@ -791,6 +792,7 @@ Pod::Spec.new do |s| 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', @@ -970,6 +972,7 @@ Pod::Spec.new do |s| 'src/core/ext/filters/client_channel/parse_address.h', 'src/core/ext/filters/client_channel/proxy_mapper.h', 'src/core/ext/filters/client_channel/proxy_mapper_registry.h', + 'src/core/ext/filters/client_channel/request_routing.h', 'src/core/ext/filters/client_channel/resolver.h', 'src/core/ext/filters/client_channel/resolver_factory.h', 'src/core/ext/filters/client_channel/resolver_registry.h', diff --git a/grpc.gemspec b/grpc.gemspec index 1ee7bec8e7..3c680b044f 100644 --- a/grpc.gemspec +++ b/grpc.gemspec @@ -285,6 +285,7 @@ Gem::Specification.new do |s| s.files += %w( src/core/ext/filters/client_channel/parse_address.h ) s.files += %w( src/core/ext/filters/client_channel/proxy_mapper.h ) s.files += %w( src/core/ext/filters/client_channel/proxy_mapper_registry.h ) + s.files += %w( src/core/ext/filters/client_channel/request_routing.h ) s.files += %w( src/core/ext/filters/client_channel/resolver.h ) s.files += %w( src/core/ext/filters/client_channel/resolver_factory.h ) s.files += %w( src/core/ext/filters/client_channel/resolver_registry.h ) @@ -730,6 +731,7 @@ Gem::Specification.new do |s| s.files += %w( src/core/ext/filters/client_channel/parse_address.cc ) s.files += %w( src/core/ext/filters/client_channel/proxy_mapper.cc ) s.files += %w( src/core/ext/filters/client_channel/proxy_mapper_registry.cc ) + s.files += %w( src/core/ext/filters/client_channel/request_routing.cc ) s.files += %w( src/core/ext/filters/client_channel/resolver.cc ) s.files += %w( src/core/ext/filters/client_channel/resolver_registry.cc ) s.files += %w( src/core/ext/filters/client_channel/resolver_result_parsing.cc ) @@ -534,6 +534,7 @@ 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', @@ -794,6 +795,7 @@ 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', @@ -1035,6 +1037,7 @@ 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', @@ -1288,6 +1291,7 @@ 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', diff --git a/package.xml b/package.xml index 68fc7433cb..2632fcb276 100644 --- a/package.xml +++ b/package.xml @@ -290,6 +290,7 @@ <file baseinstalldir="/" name="src/core/ext/filters/client_channel/parse_address.h" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/proxy_mapper.h" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/proxy_mapper_registry.h" role="src" /> + <file baseinstalldir="/" name="src/core/ext/filters/client_channel/request_routing.h" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver.h" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_factory.h" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_registry.h" role="src" /> @@ -735,6 +736,7 @@ <file baseinstalldir="/" name="src/core/ext/filters/client_channel/parse_address.cc" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/proxy_mapper.cc" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/proxy_mapper_registry.cc" role="src" /> + <file baseinstalldir="/" name="src/core/ext/filters/client_channel/request_routing.cc" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver.cc" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_registry.cc" role="src" /> <file baseinstalldir="/" name="src/core/ext/filters/client_channel/resolver_result_parsing.cc" role="src" /> diff --git a/src/core/ext/filters/client_channel/client_channel.cc b/src/core/ext/filters/client_channel/client_channel.cc index 70aac47231..dd741f1e2d 100644 --- a/src/core/ext/filters/client_channel/client_channel.cc +++ b/src/core/ext/filters/client_channel/client_channel.cc @@ -35,10 +35,10 @@ #include "src/core/ext/filters/client_channel/http_connect_handshaker.h" #include "src/core/ext/filters/client_channel/lb_policy_registry.h" #include "src/core/ext/filters/client_channel/proxy_mapper_registry.h" +#include "src/core/ext/filters/client_channel/request_routing.h" #include "src/core/ext/filters/client_channel/resolver_registry.h" #include "src/core/ext/filters/client_channel/resolver_result_parsing.h" #include "src/core/ext/filters/client_channel/retry_throttle.h" -#include "src/core/ext/filters/client_channel/server_address.h" #include "src/core/ext/filters/client_channel/subchannel.h" #include "src/core/ext/filters/deadline/deadline_filter.h" #include "src/core/lib/backoff/backoff.h" @@ -63,7 +63,6 @@ #include "src/core/lib/transport/static_metadata.h" #include "src/core/lib/transport/status_metadata.h" -using grpc_core::ServerAddressList; using grpc_core::internal::ClientChannelMethodParams; using grpc_core::internal::ClientChannelMethodParamsTable; using grpc_core::internal::ProcessedResolverResult; @@ -88,31 +87,18 @@ grpc_core::TraceFlag grpc_client_channel_trace(false, "client_channel"); struct external_connectivity_watcher; typedef struct client_channel_channel_data { - grpc_core::OrphanablePtr<grpc_core::Resolver> resolver; - bool started_resolving; + grpc_core::ManualConstructor<grpc_core::RequestRouter> request_router; + bool deadline_checking_enabled; - grpc_client_channel_factory* client_channel_factory; bool enable_retries; size_t per_rpc_retry_buffer_size; /** combiner protecting all variables below in this data structure */ grpc_combiner* combiner; - /** currently active load balancer */ - grpc_core::OrphanablePtr<grpc_core::LoadBalancingPolicy> lb_policy; /** retry throttle data */ grpc_core::RefCountedPtr<ServerRetryThrottleData> retry_throttle_data; /** maps method names to method_parameters structs */ grpc_core::RefCountedPtr<ClientChannelMethodParamsTable> method_params_table; - /** incoming resolver result - set by resolver.next() */ - grpc_channel_args* resolver_result; - /** a list of closures that are all waiting for resolver result to come in */ - grpc_closure_list waiting_for_resolver_result_closures; - /** resolver callback */ - grpc_closure on_resolver_result_changed; - /** connectivity state being tracked */ - grpc_connectivity_state_tracker state_tracker; - /** when an lb_policy arrives, should we try to exit idle */ - bool exit_idle_when_lb_policy_arrives; /** owning stack */ grpc_channel_stack* owning_stack; /** interested parties (owned) */ @@ -129,418 +115,40 @@ typedef struct client_channel_channel_data { grpc_core::UniquePtr<char> info_lb_policy_name; /** service config in JSON form */ grpc_core::UniquePtr<char> info_service_config_json; - /* backpointer to grpc_channel's channelz node */ - grpc_core::channelz::ClientChannelNode* channelz_channel; - /* caches if the last resolution event contained addresses */ - bool previous_resolution_contained_addresses; } channel_data; -typedef struct { - channel_data* chand; - /** used as an identifier, don't dereference it because the LB policy may be - * non-existing when the callback is run */ - grpc_core::LoadBalancingPolicy* lb_policy; - grpc_closure closure; -} reresolution_request_args; - -/** We create one watcher for each new lb_policy that is returned from a - resolver, to watch for state changes from the lb_policy. When a state - change is seen, we update the channel, and create a new watcher. */ -typedef struct { - channel_data* chand; - grpc_closure on_changed; - grpc_connectivity_state state; - grpc_core::LoadBalancingPolicy* lb_policy; -} lb_policy_connectivity_watcher; - -static void watch_lb_policy_locked(channel_data* chand, - grpc_core::LoadBalancingPolicy* lb_policy, - grpc_connectivity_state current_state); - -static const char* channel_connectivity_state_change_string( - grpc_connectivity_state state) { - switch (state) { - case GRPC_CHANNEL_IDLE: - return "Channel state change to IDLE"; - case GRPC_CHANNEL_CONNECTING: - return "Channel state change to CONNECTING"; - case GRPC_CHANNEL_READY: - return "Channel state change to READY"; - case GRPC_CHANNEL_TRANSIENT_FAILURE: - return "Channel state change to TRANSIENT_FAILURE"; - case GRPC_CHANNEL_SHUTDOWN: - return "Channel state change to SHUTDOWN"; - } - GPR_UNREACHABLE_CODE(return "UNKNOWN"); -} - -static void set_channel_connectivity_state_locked(channel_data* chand, - grpc_connectivity_state state, - grpc_error* error, - const char* reason) { - /* TODO: Improve failure handling: - * - Make it possible for policies to return GRPC_CHANNEL_TRANSIENT_FAILURE. - * - Hand over pending picks from old policies during the switch that happens - * when resolver provides an update. */ - if (chand->lb_policy != nullptr) { - if (state == GRPC_CHANNEL_TRANSIENT_FAILURE) { - /* cancel picks with wait_for_ready=false */ - chand->lb_policy->CancelMatchingPicksLocked( - /* mask= */ GRPC_INITIAL_METADATA_WAIT_FOR_READY, - /* check= */ 0, GRPC_ERROR_REF(error)); - } else if (state == GRPC_CHANNEL_SHUTDOWN) { - /* cancel all picks */ - chand->lb_policy->CancelMatchingPicksLocked(/* mask= */ 0, /* check= */ 0, - GRPC_ERROR_REF(error)); - } - } - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: setting connectivity state to %s", chand, - grpc_connectivity_state_name(state)); - } - if (chand->channelz_channel != nullptr) { - chand->channelz_channel->AddTraceEvent( - grpc_core::channelz::ChannelTrace::Severity::Info, - grpc_slice_from_static_string( - channel_connectivity_state_change_string(state))); - } - grpc_connectivity_state_set(&chand->state_tracker, state, error, reason); -} - -static void on_lb_policy_state_changed_locked(void* arg, grpc_error* error) { - lb_policy_connectivity_watcher* w = - static_cast<lb_policy_connectivity_watcher*>(arg); - /* check if the notification is for the latest policy */ - if (w->lb_policy == w->chand->lb_policy.get()) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: lb_policy=%p state changed to %s", w->chand, - w->lb_policy, grpc_connectivity_state_name(w->state)); - } - set_channel_connectivity_state_locked(w->chand, w->state, - GRPC_ERROR_REF(error), "lb_changed"); - if (w->state != GRPC_CHANNEL_SHUTDOWN) { - watch_lb_policy_locked(w->chand, w->lb_policy, w->state); - } - } - GRPC_CHANNEL_STACK_UNREF(w->chand->owning_stack, "watch_lb_policy"); - gpr_free(w); -} - -static void watch_lb_policy_locked(channel_data* chand, - grpc_core::LoadBalancingPolicy* lb_policy, - grpc_connectivity_state current_state) { - lb_policy_connectivity_watcher* w = - static_cast<lb_policy_connectivity_watcher*>(gpr_malloc(sizeof(*w))); - GRPC_CHANNEL_STACK_REF(chand->owning_stack, "watch_lb_policy"); - w->chand = chand; - GRPC_CLOSURE_INIT(&w->on_changed, on_lb_policy_state_changed_locked, w, - grpc_combiner_scheduler(chand->combiner)); - w->state = current_state; - w->lb_policy = lb_policy; - lb_policy->NotifyOnStateChangeLocked(&w->state, &w->on_changed); -} - -static void start_resolving_locked(channel_data* chand) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: starting name resolution", chand); - } - GPR_ASSERT(!chand->started_resolving); - chand->started_resolving = true; - GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver"); - chand->resolver->NextLocked(&chand->resolver_result, - &chand->on_resolver_result_changed); -} - -// Invoked from the resolver NextLocked() callback when the resolver -// is shutting down. -static void on_resolver_shutdown_locked(channel_data* chand, - grpc_error* error) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: shutting down", chand); - } - if (chand->lb_policy != nullptr) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: shutting down lb_policy=%p", chand, - chand->lb_policy.get()); - } - grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties(), - chand->interested_parties); - chand->lb_policy.reset(); - } - if (chand->resolver != nullptr) { - // This should never happen; it can only be triggered by a resolver - // implementation spotaneously deciding to report shutdown without - // being orphaned. This code is included just to be defensive. - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: spontaneous shutdown from resolver %p", - chand, chand->resolver.get()); - } - chand->resolver.reset(); - set_channel_connectivity_state_locked( - chand, GRPC_CHANNEL_SHUTDOWN, - GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( - "Resolver spontaneous shutdown", &error, 1), - "resolver_spontaneous_shutdown"); - } - grpc_closure_list_fail_all(&chand->waiting_for_resolver_result_closures, - GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( - "Channel disconnected", &error, 1)); - GRPC_CLOSURE_LIST_SCHED(&chand->waiting_for_resolver_result_closures); - GRPC_CHANNEL_STACK_UNREF(chand->owning_stack, "resolver"); - grpc_channel_args_destroy(chand->resolver_result); - chand->resolver_result = nullptr; - GRPC_ERROR_UNREF(error); -} - -static void request_reresolution_locked(void* arg, grpc_error* error) { - reresolution_request_args* args = - static_cast<reresolution_request_args*>(arg); - channel_data* chand = args->chand; - // If this invocation is for a stale LB policy, treat it as an LB shutdown - // signal. - if (args->lb_policy != chand->lb_policy.get() || error != GRPC_ERROR_NONE || - chand->resolver == nullptr) { - GRPC_CHANNEL_STACK_UNREF(chand->owning_stack, "re-resolution"); - gpr_free(args); - return; - } - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: started name re-resolving", chand); - } - chand->resolver->RequestReresolutionLocked(); - // Give back the closure to the LB policy. - chand->lb_policy->SetReresolutionClosureLocked(&args->closure); -} - -using TraceStringVector = grpc_core::InlinedVector<char*, 3>; - -// Creates a new LB policy, replacing any previous one. -// If the new policy is created successfully, sets *connectivity_state and -// *connectivity_error to its initial connectivity state; otherwise, -// leaves them unchanged. -static void create_new_lb_policy_locked( - channel_data* chand, char* lb_policy_name, grpc_json* lb_config, - grpc_connectivity_state* connectivity_state, - grpc_error** connectivity_error, TraceStringVector* trace_strings) { - grpc_core::LoadBalancingPolicy::Args lb_policy_args; - lb_policy_args.combiner = chand->combiner; - lb_policy_args.client_channel_factory = chand->client_channel_factory; - lb_policy_args.args = chand->resolver_result; - lb_policy_args.lb_config = lb_config; - grpc_core::OrphanablePtr<grpc_core::LoadBalancingPolicy> new_lb_policy = - grpc_core::LoadBalancingPolicyRegistry::CreateLoadBalancingPolicy( - lb_policy_name, lb_policy_args); - if (GPR_UNLIKELY(new_lb_policy == nullptr)) { - gpr_log(GPR_ERROR, "could not create LB policy \"%s\"", lb_policy_name); - if (chand->channelz_channel != nullptr) { - char* str; - gpr_asprintf(&str, "Could not create LB policy \'%s\'", lb_policy_name); - trace_strings->push_back(str); - } - } else { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: created new LB policy \"%s\" (%p)", chand, - lb_policy_name, new_lb_policy.get()); - } - if (chand->channelz_channel != nullptr) { - char* str; - gpr_asprintf(&str, "Created new LB policy \'%s\'", lb_policy_name); - trace_strings->push_back(str); - } - // Swap out the LB policy and update the fds in - // chand->interested_parties. - if (chand->lb_policy != nullptr) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: shutting down lb_policy=%p", chand, - chand->lb_policy.get()); - } - grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties(), - chand->interested_parties); - chand->lb_policy->HandOffPendingPicksLocked(new_lb_policy.get()); - } - chand->lb_policy = std::move(new_lb_policy); - grpc_pollset_set_add_pollset_set(chand->lb_policy->interested_parties(), - chand->interested_parties); - // Set up re-resolution callback. - reresolution_request_args* args = - static_cast<reresolution_request_args*>(gpr_zalloc(sizeof(*args))); - args->chand = chand; - args->lb_policy = chand->lb_policy.get(); - GRPC_CLOSURE_INIT(&args->closure, request_reresolution_locked, args, - grpc_combiner_scheduler(chand->combiner)); - GRPC_CHANNEL_STACK_REF(chand->owning_stack, "re-resolution"); - chand->lb_policy->SetReresolutionClosureLocked(&args->closure); - // Get the new LB policy's initial connectivity state and start a - // connectivity watch. - GRPC_ERROR_UNREF(*connectivity_error); - *connectivity_state = - chand->lb_policy->CheckConnectivityLocked(connectivity_error); - if (chand->exit_idle_when_lb_policy_arrives) { - chand->lb_policy->ExitIdleLocked(); - chand->exit_idle_when_lb_policy_arrives = false; - } - watch_lb_policy_locked(chand, chand->lb_policy.get(), *connectivity_state); - } -} - -static void maybe_add_trace_message_for_address_changes_locked( - channel_data* chand, TraceStringVector* trace_strings) { - const ServerAddressList* addresses = - grpc_core::FindServerAddressListChannelArg(chand->resolver_result); - const bool resolution_contains_addresses = - addresses != nullptr && addresses->size() > 0; - if (!resolution_contains_addresses && - chand->previous_resolution_contained_addresses) { - trace_strings->push_back(gpr_strdup("Address list became empty")); - } else if (resolution_contains_addresses && - !chand->previous_resolution_contained_addresses) { - trace_strings->push_back(gpr_strdup("Address list became non-empty")); - } - chand->previous_resolution_contained_addresses = - resolution_contains_addresses; -} - -static void concatenate_and_add_channel_trace_locked( - channel_data* chand, TraceStringVector* trace_strings) { - if (!trace_strings->empty()) { - gpr_strvec v; - gpr_strvec_init(&v); - gpr_strvec_add(&v, gpr_strdup("Resolution event: ")); - bool is_first = 1; - for (size_t i = 0; i < trace_strings->size(); ++i) { - if (!is_first) gpr_strvec_add(&v, gpr_strdup(", ")); - is_first = false; - gpr_strvec_add(&v, (*trace_strings)[i]); - } - char* flat; - size_t flat_len = 0; - flat = gpr_strvec_flatten(&v, &flat_len); - chand->channelz_channel->AddTraceEvent( - grpc_core::channelz::ChannelTrace::Severity::Info, - grpc_slice_new(flat, flat_len, gpr_free)); - gpr_strvec_destroy(&v); - } -} - -// Callback invoked when a resolver result is available. -static void on_resolver_result_changed_locked(void* arg, grpc_error* error) { +// Synchronous callback from chand->request_router to process a resolver +// result update. +static bool process_resolver_result_locked(void* arg, + const grpc_channel_args& args, + const char** lb_policy_name, + grpc_json** lb_policy_config) { channel_data* chand = static_cast<channel_data*>(arg); + ProcessedResolverResult resolver_result(args, chand->enable_retries); + grpc_core::UniquePtr<char> service_config_json = + resolver_result.service_config_json(); if (grpc_client_channel_trace.enabled()) { - const char* disposition = - chand->resolver_result != nullptr - ? "" - : (error == GRPC_ERROR_NONE ? " (transient error)" - : " (resolver shutdown)"); - gpr_log(GPR_INFO, - "chand=%p: got resolver result: resolver_result=%p error=%s%s", - chand, chand->resolver_result, grpc_error_string(error), - disposition); + gpr_log(GPR_INFO, "chand=%p: resolver returned service config: \"%s\"", + chand, service_config_json.get()); } - // Handle shutdown. - if (error != GRPC_ERROR_NONE || chand->resolver == nullptr) { - on_resolver_shutdown_locked(chand, GRPC_ERROR_REF(error)); - return; - } - // Data used to set the channel's connectivity state. - bool set_connectivity_state = true; - // We only want to trace the address resolution in the follow cases: - // (a) Address resolution resulted in service config change. - // (b) Address resolution that causes number of backends to go from - // zero to non-zero. - // (c) Address resolution that causes number of backends to go from - // non-zero to zero. - // (d) Address resolution that causes a new LB policy to be created. - // - // we track a list of strings to eventually be concatenated and traced. - TraceStringVector trace_strings; - grpc_connectivity_state connectivity_state = GRPC_CHANNEL_TRANSIENT_FAILURE; - grpc_error* connectivity_error = - GRPC_ERROR_CREATE_FROM_STATIC_STRING("No load balancing policy"); - // chand->resolver_result will be null in the case of a transient - // resolution error. In that case, we don't have any new result to - // process, which means that we keep using the previous result (if any). - if (chand->resolver_result == nullptr) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: resolver transient failure", chand); - } - // Don't override connectivity state if we already have an LB policy. - if (chand->lb_policy != nullptr) set_connectivity_state = false; - } else { - // Parse the resolver result. - ProcessedResolverResult resolver_result(chand->resolver_result, - chand->enable_retries); - chand->retry_throttle_data = resolver_result.retry_throttle_data(); - chand->method_params_table = resolver_result.method_params_table(); - grpc_core::UniquePtr<char> service_config_json = - resolver_result.service_config_json(); - if (service_config_json != nullptr && grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: resolver returned service config: \"%s\"", - chand, service_config_json.get()); - } - grpc_core::UniquePtr<char> lb_policy_name = - resolver_result.lb_policy_name(); - grpc_json* lb_policy_config = resolver_result.lb_policy_config(); - // Check to see if we're already using the right LB policy. - // Note: It's safe to use chand->info_lb_policy_name here without - // taking a lock on chand->info_mu, because this function is the - // only thing that modifies its value, and it can only be invoked - // once at any given time. - bool lb_policy_name_changed = - chand->info_lb_policy_name == nullptr || - strcmp(chand->info_lb_policy_name.get(), lb_policy_name.get()) != 0; - if (chand->lb_policy != nullptr && !lb_policy_name_changed) { - // Continue using the same LB policy. Update with new addresses. - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p: updating existing LB policy \"%s\" (%p)", - chand, lb_policy_name.get(), chand->lb_policy.get()); - } - chand->lb_policy->UpdateLocked(*chand->resolver_result, lb_policy_config); - // No need to set the channel's connectivity state; the existing - // watch on the LB policy will take care of that. - set_connectivity_state = false; - } else { - // Instantiate new LB policy. - create_new_lb_policy_locked(chand, lb_policy_name.get(), lb_policy_config, - &connectivity_state, &connectivity_error, - &trace_strings); - } - // Note: It's safe to use chand->info_service_config_json here without - // taking a lock on chand->info_mu, because this function is the - // only thing that modifies its value, and it can only be invoked - // once at any given time. - if (chand->channelz_channel != nullptr) { - if (((service_config_json == nullptr) != - (chand->info_service_config_json == nullptr)) || - (service_config_json != nullptr && - strcmp(service_config_json.get(), - chand->info_service_config_json.get()) != 0)) { - // TODO(ncteisen): might be worth somehow including a snippet of the - // config in the trace, at the risk of bloating the trace logs. - trace_strings.push_back(gpr_strdup("Service config changed")); - } - maybe_add_trace_message_for_address_changes_locked(chand, &trace_strings); - concatenate_and_add_channel_trace_locked(chand, &trace_strings); - } - // Swap out the data used by cc_get_channel_info(). - gpr_mu_lock(&chand->info_mu); - chand->info_lb_policy_name = std::move(lb_policy_name); - chand->info_service_config_json = std::move(service_config_json); - gpr_mu_unlock(&chand->info_mu); - // Clean up. - grpc_channel_args_destroy(chand->resolver_result); - chand->resolver_result = nullptr; - } - // Set the channel's connectivity state if needed. - if (set_connectivity_state) { - set_channel_connectivity_state_locked( - chand, connectivity_state, connectivity_error, "resolver_result"); - } else { - GRPC_ERROR_UNREF(connectivity_error); - } - // Invoke closures that were waiting for results and renew the watch. - GRPC_CLOSURE_LIST_SCHED(&chand->waiting_for_resolver_result_closures); - chand->resolver->NextLocked(&chand->resolver_result, - &chand->on_resolver_result_changed); + // Update channel state. + chand->retry_throttle_data = resolver_result.retry_throttle_data(); + chand->method_params_table = resolver_result.method_params_table(); + // Swap out the data used by cc_get_channel_info(). + gpr_mu_lock(&chand->info_mu); + chand->info_lb_policy_name = resolver_result.lb_policy_name(); + const bool service_config_changed = + ((service_config_json == nullptr) != + (chand->info_service_config_json == nullptr)) || + (service_config_json != nullptr && + strcmp(service_config_json.get(), + chand->info_service_config_json.get()) != 0); + chand->info_service_config_json = std::move(service_config_json); + gpr_mu_unlock(&chand->info_mu); + // Return results. + *lb_policy_name = chand->info_lb_policy_name.get(); + *lb_policy_config = resolver_result.lb_policy_config(); + return service_config_changed; } static void start_transport_op_locked(void* arg, grpc_error* error_ignored) { @@ -550,15 +158,14 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); if (op->on_connectivity_state_change != nullptr) { - grpc_connectivity_state_notify_on_state_change( - &chand->state_tracker, op->connectivity_state, - op->on_connectivity_state_change); + chand->request_router->NotifyOnConnectivityStateChange( + op->connectivity_state, op->on_connectivity_state_change); op->on_connectivity_state_change = nullptr; op->connectivity_state = nullptr; } if (op->send_ping.on_initiate != nullptr || op->send_ping.on_ack != nullptr) { - if (chand->lb_policy == nullptr) { + if (chand->request_router->lb_policy() == nullptr) { grpc_error* error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Ping with no load balancing"); GRPC_CLOSURE_SCHED(op->send_ping.on_initiate, GRPC_ERROR_REF(error)); @@ -567,7 +174,8 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) { grpc_error* error = GRPC_ERROR_NONE; grpc_core::LoadBalancingPolicy::PickState pick_state; // Pick must return synchronously, because pick_state.on_complete is null. - GPR_ASSERT(chand->lb_policy->PickLocked(&pick_state, &error)); + GPR_ASSERT( + chand->request_router->lb_policy()->PickLocked(&pick_state, &error)); if (pick_state.connected_subchannel != nullptr) { pick_state.connected_subchannel->Ping(op->send_ping.on_initiate, op->send_ping.on_ack); @@ -586,37 +194,14 @@ static void start_transport_op_locked(void* arg, grpc_error* error_ignored) { } if (op->disconnect_with_error != GRPC_ERROR_NONE) { - if (chand->resolver != nullptr) { - set_channel_connectivity_state_locked( - chand, GRPC_CHANNEL_SHUTDOWN, - GRPC_ERROR_REF(op->disconnect_with_error), "disconnect"); - chand->resolver.reset(); - if (!chand->started_resolving) { - grpc_closure_list_fail_all(&chand->waiting_for_resolver_result_closures, - GRPC_ERROR_REF(op->disconnect_with_error)); - GRPC_CLOSURE_LIST_SCHED(&chand->waiting_for_resolver_result_closures); - } - if (chand->lb_policy != nullptr) { - grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties(), - chand->interested_parties); - chand->lb_policy.reset(); - } - } - GRPC_ERROR_UNREF(op->disconnect_with_error); + chand->request_router->ShutdownLocked(op->disconnect_with_error); } if (op->reset_connect_backoff) { - if (chand->resolver != nullptr) { - chand->resolver->ResetBackoffLocked(); - chand->resolver->RequestReresolutionLocked(); - } - if (chand->lb_policy != nullptr) { - chand->lb_policy->ResetBackoffLocked(); - } + chand->request_router->ResetConnectionBackoffLocked(); } GRPC_CHANNEL_STACK_UNREF(chand->owning_stack, "start_transport_op"); - GRPC_CLOSURE_SCHED(op->on_consumed, GRPC_ERROR_NONE); } @@ -667,12 +252,9 @@ static grpc_error* cc_init_channel_elem(grpc_channel_element* elem, gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu); chand->owning_stack = args->channel_stack; - GRPC_CLOSURE_INIT(&chand->on_resolver_result_changed, - on_resolver_result_changed_locked, chand, - grpc_combiner_scheduler(chand->combiner)); + chand->deadline_checking_enabled = + grpc_deadline_checking_enabled(args->channel_args); chand->interested_parties = grpc_pollset_set_create(); - grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE, - "client_channel"); grpc_client_channel_start_backup_polling(chand->interested_parties); // Record max per-RPC retry buffer size. const grpc_arg* arg = grpc_channel_args_find( @@ -682,8 +264,6 @@ static grpc_error* cc_init_channel_elem(grpc_channel_element* elem, // Record enable_retries. arg = grpc_channel_args_find(args->channel_args, GRPC_ARG_ENABLE_RETRIES); chand->enable_retries = grpc_channel_arg_get_bool(arg, true); - chand->channelz_channel = nullptr; - chand->previous_resolution_contained_addresses = false; // Record client channel factory. arg = grpc_channel_args_find(args->channel_args, GRPC_ARG_CLIENT_CHANNEL_FACTORY); @@ -695,9 +275,7 @@ static grpc_error* cc_init_channel_elem(grpc_channel_element* elem, return GRPC_ERROR_CREATE_FROM_STATIC_STRING( "client channel factory arg must be a pointer"); } - grpc_client_channel_factory_ref( - static_cast<grpc_client_channel_factory*>(arg->value.pointer.p)); - chand->client_channel_factory = + grpc_client_channel_factory* client_channel_factory = static_cast<grpc_client_channel_factory*>(arg->value.pointer.p); // Get server name to resolve, using proxy mapper if needed. arg = grpc_channel_args_find(args->channel_args, GRPC_ARG_SERVER_URI); @@ -713,39 +291,24 @@ static grpc_error* cc_init_channel_elem(grpc_channel_element* elem, grpc_channel_args* new_args = nullptr; grpc_proxy_mappers_map_name(arg->value.string, args->channel_args, &proxy_name, &new_args); - // Instantiate resolver. - chand->resolver = grpc_core::ResolverRegistry::CreateResolver( - proxy_name != nullptr ? proxy_name : arg->value.string, - new_args != nullptr ? new_args : args->channel_args, - chand->interested_parties, chand->combiner); - if (proxy_name != nullptr) gpr_free(proxy_name); - if (new_args != nullptr) grpc_channel_args_destroy(new_args); - if (chand->resolver == nullptr) { - return GRPC_ERROR_CREATE_FROM_STATIC_STRING("resolver creation failed"); - } - chand->deadline_checking_enabled = - grpc_deadline_checking_enabled(args->channel_args); - return GRPC_ERROR_NONE; + // Instantiate request router. + grpc_client_channel_factory_ref(client_channel_factory); + grpc_error* error = GRPC_ERROR_NONE; + chand->request_router.Init( + chand->owning_stack, chand->combiner, client_channel_factory, + chand->interested_parties, &grpc_client_channel_trace, + process_resolver_result_locked, chand, + proxy_name != nullptr ? proxy_name : arg->value.string /* target_uri */, + new_args != nullptr ? new_args : args->channel_args, &error); + gpr_free(proxy_name); + grpc_channel_args_destroy(new_args); + return error; } /* Destructor for channel_data */ static void cc_destroy_channel_elem(grpc_channel_element* elem) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); - if (chand->resolver != nullptr) { - // The only way we can get here is if we never started resolving, - // because we take a ref to the channel stack when we start - // resolving and do not release it until the resolver callback is - // invoked after the resolver shuts down. - chand->resolver.reset(); - } - if (chand->client_channel_factory != nullptr) { - grpc_client_channel_factory_unref(chand->client_channel_factory); - } - if (chand->lb_policy != nullptr) { - grpc_pollset_set_del_pollset_set(chand->lb_policy->interested_parties(), - chand->interested_parties); - chand->lb_policy.reset(); - } + chand->request_router.Destroy(); // TODO(roth): Once we convert the filter API to C++, there will no // longer be any need to explicitly reset these smart pointer data members. chand->info_lb_policy_name.reset(); @@ -753,7 +316,6 @@ static void cc_destroy_channel_elem(grpc_channel_element* elem) { chand->retry_throttle_data.reset(); chand->method_params_table.reset(); grpc_client_channel_stop_backup_polling(chand->interested_parties); - grpc_connectivity_state_destroy(&chand->state_tracker); grpc_pollset_set_destroy(chand->interested_parties); GRPC_COMBINER_UNREF(chand->combiner, "client_channel"); gpr_mu_destroy(&chand->info_mu); @@ -810,6 +372,7 @@ static void cc_destroy_channel_elem(grpc_channel_element* elem) { // - add census stats for retries namespace { + struct call_data; // State used for starting a retryable batch on a subchannel call. @@ -894,12 +457,12 @@ struct subchannel_call_retry_state { bool completed_recv_initial_metadata : 1; bool started_recv_trailing_metadata : 1; bool completed_recv_trailing_metadata : 1; + // State for callback processing. subchannel_batch_data* recv_initial_metadata_ready_deferred_batch = nullptr; grpc_error* recv_initial_metadata_error = GRPC_ERROR_NONE; subchannel_batch_data* recv_message_ready_deferred_batch = nullptr; grpc_error* recv_message_error = GRPC_ERROR_NONE; subchannel_batch_data* recv_trailing_metadata_internal_batch = nullptr; - // State for callback processing. // NOTE: Do not move this next to the metadata bitfields above. That would // save space but will also result in a data race because compiler will // generate a 2 byte store which overwrites the meta-data fields upon @@ -908,12 +471,12 @@ struct subchannel_call_retry_state { }; // Pending batches stored in call data. -typedef struct { +struct pending_batch { // The pending batch. If nullptr, this slot is empty. grpc_transport_stream_op_batch* batch; // Indicates whether payload for send ops has been cached in call data. bool send_ops_cached; -} pending_batch; +}; /** Call data. Holds a pointer to grpc_subchannel_call and the associated machinery to create such a pointer. @@ -950,11 +513,8 @@ struct call_data { for (size_t i = 0; i < GPR_ARRAY_SIZE(pending_batches); ++i) { GPR_ASSERT(pending_batches[i].batch == nullptr); } - for (size_t i = 0; i < GRPC_CONTEXT_COUNT; ++i) { - if (pick.subchannel_call_context[i].value != nullptr) { - pick.subchannel_call_context[i].destroy( - pick.subchannel_call_context[i].value); - } + if (have_request) { + request.Destroy(); } } @@ -981,12 +541,11 @@ struct call_data { // Set when we get a cancel_stream op. grpc_error* cancel_error = GRPC_ERROR_NONE; - grpc_core::LoadBalancingPolicy::PickState pick; + grpc_core::ManualConstructor<grpc_core::RequestRouter::Request> request; + bool have_request = false; grpc_closure pick_closure; - grpc_closure pick_cancel_closure; grpc_polling_entity* pollent = nullptr; - bool pollent_added_to_interested_parties = false; // Batches are added to this list when received from above. // They are removed when we are done handling the batch (i.e., when @@ -1036,6 +595,7 @@ struct call_data { grpc_linked_mdelem* send_trailing_metadata_storage = nullptr; grpc_metadata_batch send_trailing_metadata; }; + } // namespace // Forward declarations. @@ -1438,8 +998,9 @@ static void do_retry(grpc_call_element* elem, "client_channel_call_retry"); calld->subchannel_call = nullptr; } - if (calld->pick.connected_subchannel != nullptr) { - calld->pick.connected_subchannel.reset(); + if (calld->have_request) { + calld->have_request = false; + calld->request.Destroy(); } // Compute backoff delay. grpc_millis next_attempt_time; @@ -1588,6 +1149,7 @@ static bool maybe_retry(grpc_call_element* elem, // namespace { + subchannel_batch_data::subchannel_batch_data(grpc_call_element* elem, call_data* calld, int refcount, bool set_on_complete) @@ -1628,6 +1190,7 @@ void subchannel_batch_data::destroy() { call_data* calld = static_cast<call_data*>(elem->call_data); GRPC_CALL_STACK_UNREF(calld->owning_call, "batch_data"); } + } // namespace // Creates a subchannel_batch_data object on the call's arena with the @@ -2644,17 +2207,18 @@ static void create_subchannel_call(grpc_call_element* elem, grpc_error* error) { const size_t parent_data_size = calld->enable_retries ? sizeof(subchannel_call_retry_state) : 0; const grpc_core::ConnectedSubchannel::CallArgs call_args = { - calld->pollent, // pollent - calld->path, // path - calld->call_start_time, // start_time - calld->deadline, // deadline - calld->arena, // arena - calld->pick.subchannel_call_context, // context - calld->call_combiner, // call_combiner - parent_data_size // parent_data_size + calld->pollent, // pollent + calld->path, // path + calld->call_start_time, // start_time + calld->deadline, // deadline + calld->arena, // arena + calld->request->pick()->subchannel_call_context, // context + calld->call_combiner, // call_combiner + parent_data_size // parent_data_size }; - grpc_error* new_error = calld->pick.connected_subchannel->CreateCall( - call_args, &calld->subchannel_call); + grpc_error* new_error = + calld->request->pick()->connected_subchannel->CreateCall( + call_args, &calld->subchannel_call); if (grpc_client_channel_trace.enabled()) { gpr_log(GPR_INFO, "chand=%p calld=%p: create subchannel_call=%p: error=%s", chand, calld, calld->subchannel_call, grpc_error_string(new_error)); @@ -2666,7 +2230,8 @@ static void create_subchannel_call(grpc_call_element* elem, grpc_error* error) { if (parent_data_size > 0) { new (grpc_connected_subchannel_call_get_parent_data( calld->subchannel_call)) - subchannel_call_retry_state(calld->pick.subchannel_call_context); + subchannel_call_retry_state( + calld->request->pick()->subchannel_call_context); } pending_batches_resume(elem); } @@ -2678,7 +2243,7 @@ static void pick_done(void* arg, grpc_error* error) { grpc_call_element* elem = static_cast<grpc_call_element*>(arg); channel_data* chand = static_cast<channel_data*>(elem->channel_data); call_data* calld = static_cast<call_data*>(elem->call_data); - if (GPR_UNLIKELY(calld->pick.connected_subchannel == nullptr)) { + if (GPR_UNLIKELY(calld->request->pick()->connected_subchannel == nullptr)) { // Failed to create subchannel. // If there was no error, this is an LB policy drop, in which case // we return an error; otherwise, we may retry. @@ -2707,135 +2272,27 @@ static void pick_done(void* arg, grpc_error* error) { } } -static void maybe_add_call_to_channel_interested_parties_locked( - grpc_call_element* elem) { - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (!calld->pollent_added_to_interested_parties) { - calld->pollent_added_to_interested_parties = true; - grpc_polling_entity_add_to_pollset_set(calld->pollent, - chand->interested_parties); - } -} - -static void maybe_del_call_from_channel_interested_parties_locked( - grpc_call_element* elem) { +// If the channel is in TRANSIENT_FAILURE and the call is not +// wait_for_ready=true, fails the call and returns true. +static bool fail_call_if_in_transient_failure(grpc_call_element* elem) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); call_data* calld = static_cast<call_data*>(elem->call_data); - if (calld->pollent_added_to_interested_parties) { - calld->pollent_added_to_interested_parties = false; - grpc_polling_entity_del_from_pollset_set(calld->pollent, - chand->interested_parties); + grpc_transport_stream_op_batch* batch = calld->pending_batches[0].batch; + if (chand->request_router->GetConnectivityState() == + GRPC_CHANNEL_TRANSIENT_FAILURE && + (batch->payload->send_initial_metadata.send_initial_metadata_flags & + GRPC_INITIAL_METADATA_WAIT_FOR_READY) == 0) { + pending_batches_fail( + elem, + grpc_error_set_int(GRPC_ERROR_CREATE_FROM_STATIC_STRING( + "channel is in state TRANSIENT_FAILURE"), + GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE), + true /* yield_call_combiner */); + return true; } + return false; } -// Invoked when a pick is completed to leave the client_channel combiner -// and continue processing in the call combiner. -// If needed, removes the call's polling entity from chand->interested_parties. -static void pick_done_locked(grpc_call_element* elem, grpc_error* error) { - call_data* calld = static_cast<call_data*>(elem->call_data); - maybe_del_call_from_channel_interested_parties_locked(elem); - GRPC_CLOSURE_INIT(&calld->pick_closure, pick_done, elem, - grpc_schedule_on_exec_ctx); - GRPC_CLOSURE_SCHED(&calld->pick_closure, error); -} - -namespace grpc_core { - -// Performs subchannel pick via LB policy. -class LbPicker { - public: - // Starts a pick on chand->lb_policy. - static void StartLocked(grpc_call_element* elem) { - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: starting pick on lb_policy=%p", - chand, calld, chand->lb_policy.get()); - } - // If this is a retry, use the send_initial_metadata payload that - // we've cached; otherwise, use the pending batch. The - // send_initial_metadata batch will be the first pending batch in the - // list, as set by get_batch_index() above. - calld->pick.initial_metadata = - calld->seen_send_initial_metadata - ? &calld->send_initial_metadata - : calld->pending_batches[0] - .batch->payload->send_initial_metadata.send_initial_metadata; - calld->pick.initial_metadata_flags = - calld->seen_send_initial_metadata - ? calld->send_initial_metadata_flags - : calld->pending_batches[0] - .batch->payload->send_initial_metadata - .send_initial_metadata_flags; - GRPC_CLOSURE_INIT(&calld->pick_closure, &LbPicker::DoneLocked, elem, - grpc_combiner_scheduler(chand->combiner)); - calld->pick.on_complete = &calld->pick_closure; - GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback"); - grpc_error* error = GRPC_ERROR_NONE; - const bool pick_done = chand->lb_policy->PickLocked(&calld->pick, &error); - if (GPR_LIKELY(pick_done)) { - // Pick completed synchronously. - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed synchronously", - chand, calld); - } - pick_done_locked(elem, error); - GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback"); - } else { - // Pick will be returned asynchronously. - // Add the polling entity from call_data to the channel_data's - // interested_parties, so that the I/O of the LB policy can be done - // under it. It will be removed in pick_done_locked(). - maybe_add_call_to_channel_interested_parties_locked(elem); - // Request notification on call cancellation. - GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback_cancel"); - grpc_call_combiner_set_notify_on_cancel( - calld->call_combiner, - GRPC_CLOSURE_INIT(&calld->pick_cancel_closure, - &LbPicker::CancelLocked, elem, - grpc_combiner_scheduler(chand->combiner))); - } - } - - private: - // Callback invoked by LoadBalancingPolicy::PickLocked() for async picks. - // Unrefs the LB policy and invokes pick_done_locked(). - static void DoneLocked(void* arg, grpc_error* error) { - grpc_call_element* elem = static_cast<grpc_call_element*>(arg); - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed asynchronously", - chand, calld); - } - pick_done_locked(elem, GRPC_ERROR_REF(error)); - GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback"); - } - - // Note: This runs under the client_channel combiner, but will NOT be - // holding the call combiner. - static void CancelLocked(void* arg, grpc_error* error) { - grpc_call_element* elem = static_cast<grpc_call_element*>(arg); - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - // Note: chand->lb_policy may have changed since we started our pick, - // in which case we will be cancelling the pick on a policy other than - // the one we started it on. However, this will just be a no-op. - if (GPR_UNLIKELY(error != GRPC_ERROR_NONE && chand->lb_policy != nullptr)) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, - "chand=%p calld=%p: cancelling pick from LB policy %p", chand, - calld, chand->lb_policy.get()); - } - chand->lb_policy->CancelPickLocked(&calld->pick, GRPC_ERROR_REF(error)); - } - GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback_cancel"); - } -}; - -} // namespace grpc_core - // Applies service config to the call. Must be invoked once we know // that the resolver has returned results to the channel. static void apply_service_config_to_call_locked(grpc_call_element* elem) { @@ -2892,224 +2349,66 @@ static void apply_service_config_to_call_locked(grpc_call_element* elem) { } } -// If the channel is in TRANSIENT_FAILURE and the call is not -// wait_for_ready=true, fails the call and returns true. -static bool fail_call_if_in_transient_failure(grpc_call_element* elem) { - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - grpc_transport_stream_op_batch* batch = calld->pending_batches[0].batch; - if (grpc_connectivity_state_check(&chand->state_tracker) == - GRPC_CHANNEL_TRANSIENT_FAILURE && - (batch->payload->send_initial_metadata.send_initial_metadata_flags & - GRPC_INITIAL_METADATA_WAIT_FOR_READY) == 0) { - pending_batches_fail( - elem, - grpc_error_set_int(GRPC_ERROR_CREATE_FROM_STATIC_STRING( - "channel is in state TRANSIENT_FAILURE"), - GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE), - true /* yield_call_combiner */); - return true; - } - return false; -} - // Invoked once resolver results are available. -static void process_service_config_and_start_lb_pick_locked( - grpc_call_element* elem) { +static bool maybe_apply_service_config_to_call_locked(void* arg) { + grpc_call_element* elem = static_cast<grpc_call_element*>(arg); call_data* calld = static_cast<call_data*>(elem->call_data); // Only get service config data on the first attempt. if (GPR_LIKELY(calld->num_attempts_completed == 0)) { apply_service_config_to_call_locked(elem); // Check this after applying service config, since it may have // affected the call's wait_for_ready value. - if (fail_call_if_in_transient_failure(elem)) return; + if (fail_call_if_in_transient_failure(elem)) return false; } - // Start LB pick. - grpc_core::LbPicker::StartLocked(elem); + return true; } -namespace grpc_core { - -// Handles waiting for a resolver result. -// Used only for the first call on an idle channel. -class ResolverResultWaiter { - public: - explicit ResolverResultWaiter(grpc_call_element* elem) : elem_(elem) { - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, - "chand=%p calld=%p: deferring pick pending resolver result", - chand, calld); - } - // Add closure to be run when a resolver result is available. - GRPC_CLOSURE_INIT(&done_closure_, &ResolverResultWaiter::DoneLocked, this, - grpc_combiner_scheduler(chand->combiner)); - AddToWaitingList(); - // Set cancellation closure, so that we abort if the call is cancelled. - GRPC_CLOSURE_INIT(&cancel_closure_, &ResolverResultWaiter::CancelLocked, - this, grpc_combiner_scheduler(chand->combiner)); - grpc_call_combiner_set_notify_on_cancel(calld->call_combiner, - &cancel_closure_); - } - - private: - // Adds closure_ to chand->waiting_for_resolver_result_closures. - void AddToWaitingList() { - channel_data* chand = static_cast<channel_data*>(elem_->channel_data); - grpc_closure_list_append(&chand->waiting_for_resolver_result_closures, - &done_closure_, GRPC_ERROR_NONE); - } - - // Invoked when a resolver result is available. - static void DoneLocked(void* arg, grpc_error* error) { - ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg); - // If CancelLocked() has already run, delete ourselves without doing - // anything. Note that the call stack may have already been destroyed, - // so it's not safe to access anything in elem_. - if (GPR_UNLIKELY(self->finished_)) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "call cancelled before resolver result"); - } - Delete(self); - return; - } - // Otherwise, process the resolver result. - grpc_call_element* elem = self->elem_; - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: resolver failed to return data", - chand, calld); - } - pick_done_locked(elem, GRPC_ERROR_REF(error)); - } else if (GPR_UNLIKELY(chand->resolver == nullptr)) { - // Shutting down. - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: resolver disconnected", chand, - calld); - } - pick_done_locked(elem, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected")); - } else if (GPR_UNLIKELY(chand->lb_policy == nullptr)) { - // Transient resolver failure. - // If call has wait_for_ready=true, try again; otherwise, fail. - uint32_t send_initial_metadata_flags = - calld->seen_send_initial_metadata - ? calld->send_initial_metadata_flags - : calld->pending_batches[0] - .batch->payload->send_initial_metadata - .send_initial_metadata_flags; - if (send_initial_metadata_flags & GRPC_INITIAL_METADATA_WAIT_FOR_READY) { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, - "chand=%p calld=%p: resolver returned but no LB policy; " - "wait_for_ready=true; trying again", - chand, calld); - } - // Re-add ourselves to the waiting list. - self->AddToWaitingList(); - // Return early so that we don't set finished_ to true below. - return; - } else { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, - "chand=%p calld=%p: resolver returned but no LB policy; " - "wait_for_ready=false; failing", - chand, calld); - } - pick_done_locked( - elem, - grpc_error_set_int( - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Name resolution failure"), - GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE)); - } - } else { - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, "chand=%p calld=%p: resolver returned, doing LB pick", - chand, calld); - } - process_service_config_and_start_lb_pick_locked(elem); - } - self->finished_ = true; - } - - // Invoked when the call is cancelled. - // Note: This runs under the client_channel combiner, but will NOT be - // holding the call combiner. - static void CancelLocked(void* arg, grpc_error* error) { - ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg); - // If DoneLocked() has already run, delete ourselves without doing anything. - if (GPR_LIKELY(self->finished_)) { - Delete(self); - return; - } - // If we are being cancelled, immediately invoke pick_done_locked() - // to propagate the error back to the caller. - if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) { - grpc_call_element* elem = self->elem_; - channel_data* chand = static_cast<channel_data*>(elem->channel_data); - call_data* calld = static_cast<call_data*>(elem->call_data); - if (grpc_client_channel_trace.enabled()) { - gpr_log(GPR_INFO, - "chand=%p calld=%p: cancelling call waiting for name " - "resolution", - chand, calld); - } - // Note: Although we are not in the call combiner here, we are - // basically stealing the call combiner from the pending pick, so - // it's safe to call pick_done_locked() here -- we are essentially - // calling it here instead of calling it in DoneLocked(). - pick_done_locked(elem, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( - "Pick cancelled", &error, 1)); - } - self->finished_ = true; - } - - grpc_call_element* elem_; - grpc_closure done_closure_; - grpc_closure cancel_closure_; - bool finished_ = false; -}; - -} // namespace grpc_core - static void start_pick_locked(void* arg, grpc_error* ignored) { grpc_call_element* elem = static_cast<grpc_call_element*>(arg); call_data* calld = static_cast<call_data*>(elem->call_data); channel_data* chand = static_cast<channel_data*>(elem->channel_data); - GPR_ASSERT(calld->pick.connected_subchannel == nullptr); + GPR_ASSERT(!calld->have_request); GPR_ASSERT(calld->subchannel_call == nullptr); - if (GPR_LIKELY(chand->lb_policy != nullptr)) { - // We already have resolver results, so process the service config - // and start an LB pick. - process_service_config_and_start_lb_pick_locked(elem); - } else if (GPR_UNLIKELY(chand->resolver == nullptr)) { - pick_done_locked(elem, - GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected")); - } else { - // We do not yet have an LB policy, so wait for a resolver result. - if (GPR_UNLIKELY(!chand->started_resolving)) { - start_resolving_locked(chand); - } else { - // Normally, we want to do this check in - // process_service_config_and_start_lb_pick_locked(), so that we - // can honor the wait_for_ready setting in the service config. - // However, if the channel is in TRANSIENT_FAILURE at this point, that - // means that the resolver has returned a failure, so we're not going - // to get a service config right away. In that case, we fail the - // call now based on the wait_for_ready value passed in from the - // application. - if (fail_call_if_in_transient_failure(elem)) return; - } - // Create a new waiter, which will delete itself when done. - grpc_core::New<grpc_core::ResolverResultWaiter>(elem); - // Add the polling entity from call_data to the channel_data's - // interested_parties, so that the I/O of the resolver can be done - // under it. It will be removed in pick_done_locked(). - maybe_add_call_to_channel_interested_parties_locked(elem); + // Normally, we want to do this check until after we've processed the + // service config, so that we can honor the wait_for_ready setting in + // the service config. However, if the channel is in TRANSIENT_FAILURE + // and we don't have an LB policy at this point, that means that the + // resolver has returned a failure, so we're not going to get a service + // config right away. In that case, we fail the call now based on the + // wait_for_ready value passed in from the application. + if (chand->request_router->lb_policy() == nullptr && + fail_call_if_in_transient_failure(elem)) { + return; } + // If this is a retry, use the send_initial_metadata payload that + // we've cached; otherwise, use the pending batch. The + // send_initial_metadata batch will be the first pending batch in the + // list, as set by get_batch_index() above. + // TODO(roth): What if the LB policy needs to add something to the + // call's initial metadata, and then there's a retry? We don't want + // the new metadata to be added twice. We might need to somehow + // allocate the subchannel batch earlier so that we can give the + // subchannel's copy of the metadata batch (which is copied for each + // attempt) to the LB policy instead the one from the parent channel. + grpc_metadata_batch* initial_metadata = + calld->seen_send_initial_metadata + ? &calld->send_initial_metadata + : calld->pending_batches[0] + .batch->payload->send_initial_metadata.send_initial_metadata; + uint32_t* initial_metadata_flags = + calld->seen_send_initial_metadata + ? &calld->send_initial_metadata_flags + : &calld->pending_batches[0] + .batch->payload->send_initial_metadata + .send_initial_metadata_flags; + GRPC_CLOSURE_INIT(&calld->pick_closure, pick_done, elem, + grpc_schedule_on_exec_ctx); + calld->request.Init(calld->owning_call, calld->call_combiner, calld->pollent, + initial_metadata, initial_metadata_flags, + maybe_apply_service_config_to_call_locked, elem, + &calld->pick_closure); + calld->have_request = true; + chand->request_router->RouteCallLocked(calld->request.get()); } // @@ -3249,23 +2548,10 @@ const grpc_channel_filter grpc_client_channel_filter = { "client-channel", }; -static void try_to_connect_locked(void* arg, grpc_error* error_ignored) { - channel_data* chand = static_cast<channel_data*>(arg); - if (chand->lb_policy != nullptr) { - chand->lb_policy->ExitIdleLocked(); - } else { - chand->exit_idle_when_lb_policy_arrives = true; - if (!chand->started_resolving && chand->resolver != nullptr) { - start_resolving_locked(chand); - } - } - GRPC_CHANNEL_STACK_UNREF(chand->owning_stack, "try_to_connect"); -} - void grpc_client_channel_set_channelz_node( grpc_channel_element* elem, grpc_core::channelz::ClientChannelNode* node) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); - chand->channelz_channel = node; + chand->request_router->set_channelz_node(node); } void grpc_client_channel_populate_child_refs( @@ -3273,17 +2559,22 @@ void grpc_client_channel_populate_child_refs( grpc_core::channelz::ChildRefsList* child_subchannels, grpc_core::channelz::ChildRefsList* child_channels) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); - if (chand->lb_policy != nullptr) { - chand->lb_policy->FillChildRefsForChannelz(child_subchannels, - child_channels); + if (chand->request_router->lb_policy() != nullptr) { + chand->request_router->lb_policy()->FillChildRefsForChannelz( + child_subchannels, child_channels); } } +static void try_to_connect_locked(void* arg, grpc_error* error_ignored) { + channel_data* chand = static_cast<channel_data*>(arg); + chand->request_router->ExitIdleLocked(); + GRPC_CHANNEL_STACK_UNREF(chand->owning_stack, "try_to_connect"); +} + grpc_connectivity_state grpc_client_channel_check_connectivity_state( grpc_channel_element* elem, int try_to_connect) { channel_data* chand = static_cast<channel_data*>(elem->channel_data); - grpc_connectivity_state out = - grpc_connectivity_state_check(&chand->state_tracker); + grpc_connectivity_state out = chand->request_router->GetConnectivityState(); if (out == GRPC_CHANNEL_IDLE && try_to_connect) { GRPC_CHANNEL_STACK_REF(chand->owning_stack, "try_to_connect"); GRPC_CLOSURE_SCHED( @@ -3328,19 +2619,19 @@ static void external_connectivity_watcher_list_append( } static void external_connectivity_watcher_list_remove( - channel_data* chand, external_connectivity_watcher* too_remove) { + channel_data* chand, external_connectivity_watcher* to_remove) { GPR_ASSERT( - lookup_external_connectivity_watcher(chand, too_remove->on_complete)); + lookup_external_connectivity_watcher(chand, to_remove->on_complete)); gpr_mu_lock(&chand->external_connectivity_watcher_list_mu); - if (too_remove == chand->external_connectivity_watcher_list_head) { - chand->external_connectivity_watcher_list_head = too_remove->next; + if (to_remove == chand->external_connectivity_watcher_list_head) { + chand->external_connectivity_watcher_list_head = to_remove->next; gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu); return; } external_connectivity_watcher* w = chand->external_connectivity_watcher_list_head; while (w != nullptr) { - if (w->next == too_remove) { + if (w->next == to_remove) { w->next = w->next->next; gpr_mu_unlock(&chand->external_connectivity_watcher_list_mu); return; @@ -3392,15 +2683,15 @@ static void watch_connectivity_state_locked(void* arg, GRPC_CLOSURE_RUN(w->watcher_timer_init, GRPC_ERROR_NONE); GRPC_CLOSURE_INIT(&w->my_closure, on_external_watch_complete_locked, w, grpc_combiner_scheduler(w->chand->combiner)); - grpc_connectivity_state_notify_on_state_change(&w->chand->state_tracker, - w->state, &w->my_closure); + w->chand->request_router->NotifyOnConnectivityStateChange(w->state, + &w->my_closure); } else { GPR_ASSERT(w->watcher_timer_init == nullptr); found = lookup_external_connectivity_watcher(w->chand, w->on_complete); if (found) { GPR_ASSERT(found->on_complete == w->on_complete); - grpc_connectivity_state_notify_on_state_change( - &found->chand->state_tracker, nullptr, &found->my_closure); + found->chand->request_router->NotifyOnConnectivityStateChange( + nullptr, &found->my_closure); } grpc_polling_entity_del_from_pollset_set(&w->pollent, w->chand->interested_parties); diff --git a/src/core/ext/filters/client_channel/lb_policy.h b/src/core/ext/filters/client_channel/lb_policy.h index 29b8c28be6..293d8e960c 100644 --- a/src/core/ext/filters/client_channel/lb_policy.h +++ b/src/core/ext/filters/client_channel/lb_policy.h @@ -65,10 +65,10 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> { struct PickState { /// Initial metadata associated with the picking call. grpc_metadata_batch* initial_metadata = nullptr; - /// Bitmask used for selective cancelling. See + /// Pointer to bitmask used for selective cancelling. See /// \a CancelMatchingPicksLocked() and \a GRPC_INITIAL_METADATA_* in /// grpc_types.h. - uint32_t initial_metadata_flags = 0; + uint32_t* initial_metadata_flags = nullptr; /// Storage for LB token in \a initial_metadata, or nullptr if not used. grpc_linked_mdelem lb_token_mdelem_storage; /// Closure to run when pick is complete, if not completed synchronously. @@ -88,6 +88,9 @@ class LoadBalancingPolicy : public InternallyRefCounted<LoadBalancingPolicy> { LoadBalancingPolicy(const LoadBalancingPolicy&) = delete; LoadBalancingPolicy& operator=(const LoadBalancingPolicy&) = delete; + /// Returns the name of the LB policy. + virtual const char* name() const GRPC_ABSTRACT; + /// Updates the policy with a new set of \a args and a new \a lb_config from /// the resolver. Note that the LB policy gets the set of addresses from the /// GRPC_ARG_SERVER_ADDRESS_LIST channel arg. diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc index 3c4f0d6552..ba40febd53 100644 --- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc +++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc @@ -122,10 +122,14 @@ TraceFlag grpc_lb_glb_trace(false, "glb"); namespace { +constexpr char kGrpclb[] = "grpclb"; + class GrpcLb : public LoadBalancingPolicy { public: explicit GrpcLb(const Args& args); + const char* name() const override { return kGrpclb; } + void UpdateLocked(const grpc_channel_args& args, grpc_json* lb_config) override; bool PickLocked(PickState* pick, grpc_error** error) override; @@ -1136,7 +1140,7 @@ void GrpcLb::CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask, pending_picks_ = nullptr; while (pp != nullptr) { PendingPick* next = pp->next; - if ((pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == + if ((*pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == initial_metadata_flags_eq) { // Note: pp is deleted in this callback. GRPC_CLOSURE_SCHED(&pp->on_complete, @@ -1819,7 +1823,7 @@ class GrpcLbFactory : public LoadBalancingPolicyFactory { return OrphanablePtr<LoadBalancingPolicy>(New<GrpcLb>(args)); } - const char* name() const override { return "grpclb"; } + const char* name() const override { return kGrpclb; } }; } // namespace diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc index 74c17612a2..d6ff74ec7f 100644 --- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc +++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc @@ -43,10 +43,14 @@ namespace { // pick_first LB policy // +constexpr char kPickFirst[] = "pick_first"; + class PickFirst : public LoadBalancingPolicy { public: explicit PickFirst(const Args& args); + const char* name() const override { return kPickFirst; } + void UpdateLocked(const grpc_channel_args& args, grpc_json* lb_config) override; bool PickLocked(PickState* pick, grpc_error** error) override; @@ -234,7 +238,7 @@ void PickFirst::CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask, pending_picks_ = nullptr; while (pick != nullptr) { PickState* next = pick->next; - if ((pick->initial_metadata_flags & initial_metadata_flags_mask) == + if ((*pick->initial_metadata_flags & initial_metadata_flags_mask) == initial_metadata_flags_eq) { GRPC_CLOSURE_SCHED(pick->on_complete, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( @@ -622,7 +626,7 @@ class PickFirstFactory : public LoadBalancingPolicyFactory { return OrphanablePtr<LoadBalancingPolicy>(New<PickFirst>(args)); } - const char* name() const override { return "pick_first"; } + const char* name() const override { return kPickFirst; } }; } // namespace diff --git a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc index 63089afbd7..3bcb33ef11 100644 --- a/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc +++ b/src/core/ext/filters/client_channel/lb_policy/round_robin/round_robin.cc @@ -53,10 +53,14 @@ namespace { // round_robin LB policy // +constexpr char kRoundRobin[] = "round_robin"; + class RoundRobin : public LoadBalancingPolicy { public: explicit RoundRobin(const Args& args); + const char* name() const override { return kRoundRobin; } + void UpdateLocked(const grpc_channel_args& args, grpc_json* lb_config) override; bool PickLocked(PickState* pick, grpc_error** error) override; @@ -291,7 +295,7 @@ void RoundRobin::CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask, pending_picks_ = nullptr; while (pick != nullptr) { PickState* next = pick->next; - if ((pick->initial_metadata_flags & initial_metadata_flags_mask) == + if ((*pick->initial_metadata_flags & initial_metadata_flags_mask) == initial_metadata_flags_eq) { pick->connected_subchannel.reset(); GRPC_CLOSURE_SCHED(pick->on_complete, @@ -700,7 +704,7 @@ class RoundRobinFactory : public LoadBalancingPolicyFactory { return OrphanablePtr<LoadBalancingPolicy>(New<RoundRobin>(args)); } - const char* name() const override { return "round_robin"; } + const char* name() const override { return kRoundRobin; } }; } // namespace diff --git a/src/core/ext/filters/client_channel/lb_policy/xds/xds.cc b/src/core/ext/filters/client_channel/lb_policy/xds/xds.cc index 3c25de2386..8787f5bcc2 100644 --- a/src/core/ext/filters/client_channel/lb_policy/xds/xds.cc +++ b/src/core/ext/filters/client_channel/lb_policy/xds/xds.cc @@ -115,10 +115,14 @@ TraceFlag grpc_lb_xds_trace(false, "xds"); namespace { +constexpr char kXds[] = "xds_experimental"; + class XdsLb : public LoadBalancingPolicy { public: explicit XdsLb(const Args& args); + const char* name() const override { return kXds; } + void UpdateLocked(const grpc_channel_args& args, grpc_json* lb_config) override; bool PickLocked(PickState* pick, grpc_error** error) override; @@ -1053,7 +1057,7 @@ void XdsLb::CancelMatchingPicksLocked(uint32_t initial_metadata_flags_mask, pending_picks_ = nullptr; while (pp != nullptr) { PendingPick* next = pp->next; - if ((pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == + if ((*pp->pick->initial_metadata_flags & initial_metadata_flags_mask) == initial_metadata_flags_eq) { // Note: pp is deleted in this callback. GRPC_CLOSURE_SCHED(&pp->on_complete, @@ -1651,7 +1655,7 @@ class XdsFactory : public LoadBalancingPolicyFactory { return OrphanablePtr<LoadBalancingPolicy>(New<XdsLb>(args)); } - const char* name() const override { return "xds_experimental"; } + const char* name() const override { return kXds; } }; } // namespace diff --git a/src/core/ext/filters/client_channel/request_routing.cc b/src/core/ext/filters/client_channel/request_routing.cc new file mode 100644 index 0000000000..f9a7e164e7 --- /dev/null +++ b/src/core/ext/filters/client_channel/request_routing.cc @@ -0,0 +1,936 @@ +/* + * + * Copyright 2015 gRPC authors. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + */ + +#include <grpc/support/port_platform.h> + +#include "src/core/ext/filters/client_channel/request_routing.h" + +#include <inttypes.h> +#include <limits.h> +#include <stdbool.h> +#include <stdio.h> +#include <string.h> + +#include <grpc/support/alloc.h> +#include <grpc/support/log.h> +#include <grpc/support/string_util.h> +#include <grpc/support/sync.h> + +#include "src/core/ext/filters/client_channel/backup_poller.h" +#include "src/core/ext/filters/client_channel/http_connect_handshaker.h" +#include "src/core/ext/filters/client_channel/lb_policy_registry.h" +#include "src/core/ext/filters/client_channel/proxy_mapper_registry.h" +#include "src/core/ext/filters/client_channel/resolver_registry.h" +#include "src/core/ext/filters/client_channel/retry_throttle.h" +#include "src/core/ext/filters/client_channel/server_address.h" +#include "src/core/ext/filters/client_channel/subchannel.h" +#include "src/core/ext/filters/deadline/deadline_filter.h" +#include "src/core/lib/backoff/backoff.h" +#include "src/core/lib/channel/channel_args.h" +#include "src/core/lib/channel/connected_channel.h" +#include "src/core/lib/channel/status_util.h" +#include "src/core/lib/gpr/string.h" +#include "src/core/lib/gprpp/inlined_vector.h" +#include "src/core/lib/gprpp/manual_constructor.h" +#include "src/core/lib/iomgr/combiner.h" +#include "src/core/lib/iomgr/iomgr.h" +#include "src/core/lib/iomgr/polling_entity.h" +#include "src/core/lib/profiling/timers.h" +#include "src/core/lib/slice/slice_internal.h" +#include "src/core/lib/slice/slice_string_helpers.h" +#include "src/core/lib/surface/channel.h" +#include "src/core/lib/transport/connectivity_state.h" +#include "src/core/lib/transport/error_utils.h" +#include "src/core/lib/transport/metadata.h" +#include "src/core/lib/transport/metadata_batch.h" +#include "src/core/lib/transport/service_config.h" +#include "src/core/lib/transport/static_metadata.h" +#include "src/core/lib/transport/status_metadata.h" + +namespace grpc_core { + +// +// RequestRouter::Request::ResolverResultWaiter +// + +// Handles waiting for a resolver result. +// Used only for the first call on an idle channel. +class RequestRouter::Request::ResolverResultWaiter { + public: + explicit ResolverResultWaiter(Request* request) + : request_router_(request->request_router_), + request_(request), + tracer_enabled_(request_router_->tracer_->enabled()) { + if (tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: deferring pick pending resolver " + "result", + request_router_, request); + } + // Add closure to be run when a resolver result is available. + GRPC_CLOSURE_INIT(&done_closure_, &DoneLocked, this, + grpc_combiner_scheduler(request_router_->combiner_)); + AddToWaitingList(); + // Set cancellation closure, so that we abort if the call is cancelled. + GRPC_CLOSURE_INIT(&cancel_closure_, &CancelLocked, this, + grpc_combiner_scheduler(request_router_->combiner_)); + grpc_call_combiner_set_notify_on_cancel(request->call_combiner_, + &cancel_closure_); + } + + private: + // Adds done_closure_ to + // request_router_->waiting_for_resolver_result_closures_. + void AddToWaitingList() { + grpc_closure_list_append( + &request_router_->waiting_for_resolver_result_closures_, &done_closure_, + GRPC_ERROR_NONE); + } + + // Invoked when a resolver result is available. + static void DoneLocked(void* arg, grpc_error* error) { + ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg); + RequestRouter* request_router = self->request_router_; + // If CancelLocked() has already run, delete ourselves without doing + // anything. Note that the call stack may have already been destroyed, + // so it's not safe to access anything in state_. + if (GPR_UNLIKELY(self->finished_)) { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p: call cancelled before resolver result", + request_router); + } + Delete(self); + return; + } + // Otherwise, process the resolver result. + Request* request = self->request_; + if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: resolver failed to return data", + request_router, request); + } + GRPC_CLOSURE_RUN(request->on_route_done_, GRPC_ERROR_REF(error)); + } else if (GPR_UNLIKELY(request_router->resolver_ == nullptr)) { + // Shutting down. + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, "request_router=%p request=%p: resolver disconnected", + request_router, request); + } + GRPC_CLOSURE_RUN(request->on_route_done_, + GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected")); + } else if (GPR_UNLIKELY(request_router->lb_policy_ == nullptr)) { + // Transient resolver failure. + // If call has wait_for_ready=true, try again; otherwise, fail. + if (*request->pick_.initial_metadata_flags & + GRPC_INITIAL_METADATA_WAIT_FOR_READY) { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: resolver returned but no LB " + "policy; wait_for_ready=true; trying again", + request_router, request); + } + // Re-add ourselves to the waiting list. + self->AddToWaitingList(); + // Return early so that we don't set finished_ to true below. + return; + } else { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: resolver returned but no LB " + "policy; wait_for_ready=false; failing", + request_router, request); + } + GRPC_CLOSURE_RUN( + request->on_route_done_, + grpc_error_set_int( + GRPC_ERROR_CREATE_FROM_STATIC_STRING("Name resolution failure"), + GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE)); + } + } else { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: resolver returned, doing LB " + "pick", + request_router, request); + } + request->ProcessServiceConfigAndStartLbPickLocked(); + } + self->finished_ = true; + } + + // Invoked when the call is cancelled. + // Note: This runs under the client_channel combiner, but will NOT be + // holding the call combiner. + static void CancelLocked(void* arg, grpc_error* error) { + ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg); + RequestRouter* request_router = self->request_router_; + // If DoneLocked() has already run, delete ourselves without doing anything. + if (self->finished_) { + Delete(self); + return; + } + Request* request = self->request_; + // If we are being cancelled, immediately invoke on_route_done_ + // to propagate the error back to the caller. + if (error != GRPC_ERROR_NONE) { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: cancelling call waiting for " + "name resolution", + request_router, request); + } + // Note: Although we are not in the call combiner here, we are + // basically stealing the call combiner from the pending pick, so + // it's safe to run on_route_done_ here -- we are essentially + // calling it here instead of calling it in DoneLocked(). + GRPC_CLOSURE_RUN(request->on_route_done_, + GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( + "Pick cancelled", &error, 1)); + } + self->finished_ = true; + } + + RequestRouter* request_router_; + Request* request_; + const bool tracer_enabled_; + grpc_closure done_closure_; + grpc_closure cancel_closure_; + bool finished_ = false; +}; + +// +// RequestRouter::Request::AsyncPickCanceller +// + +// Handles the call combiner cancellation callback for an async LB pick. +class RequestRouter::Request::AsyncPickCanceller { + public: + explicit AsyncPickCanceller(Request* request) + : request_router_(request->request_router_), + request_(request), + tracer_enabled_(request_router_->tracer_->enabled()) { + GRPC_CALL_STACK_REF(request->owning_call_, "pick_callback_cancel"); + // Set cancellation closure, so that we abort if the call is cancelled. + GRPC_CLOSURE_INIT(&cancel_closure_, &CancelLocked, this, + grpc_combiner_scheduler(request_router_->combiner_)); + grpc_call_combiner_set_notify_on_cancel(request->call_combiner_, + &cancel_closure_); + } + + void MarkFinishedLocked() { + finished_ = true; + GRPC_CALL_STACK_UNREF(request_->owning_call_, "pick_callback_cancel"); + } + + private: + // Invoked when the call is cancelled. + // Note: This runs under the client_channel combiner, but will NOT be + // holding the call combiner. + static void CancelLocked(void* arg, grpc_error* error) { + AsyncPickCanceller* self = static_cast<AsyncPickCanceller*>(arg); + Request* request = self->request_; + RequestRouter* request_router = self->request_router_; + if (!self->finished_) { + // Note: request_router->lb_policy_ may have changed since we started our + // pick, in which case we will be cancelling the pick on a policy other + // than the one we started it on. However, this will just be a no-op. + if (error != GRPC_ERROR_NONE && request_router->lb_policy_ != nullptr) { + if (self->tracer_enabled_) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: cancelling pick from LB " + "policy %p", + request_router, request, request_router->lb_policy_.get()); + } + request_router->lb_policy_->CancelPickLocked(&request->pick_, + GRPC_ERROR_REF(error)); + } + request->pick_canceller_ = nullptr; + GRPC_CALL_STACK_UNREF(request->owning_call_, "pick_callback_cancel"); + } + Delete(self); + } + + RequestRouter* request_router_; + Request* request_; + const bool tracer_enabled_; + grpc_closure cancel_closure_; + bool finished_ = false; +}; + +// +// RequestRouter::Request +// + +RequestRouter::Request::Request(grpc_call_stack* owning_call, + grpc_call_combiner* call_combiner, + grpc_polling_entity* pollent, + grpc_metadata_batch* send_initial_metadata, + uint32_t* send_initial_metadata_flags, + ApplyServiceConfigCallback apply_service_config, + void* apply_service_config_user_data, + grpc_closure* on_route_done) + : owning_call_(owning_call), + call_combiner_(call_combiner), + pollent_(pollent), + apply_service_config_(apply_service_config), + apply_service_config_user_data_(apply_service_config_user_data), + on_route_done_(on_route_done) { + pick_.initial_metadata = send_initial_metadata; + pick_.initial_metadata_flags = send_initial_metadata_flags; +} + +RequestRouter::Request::~Request() { + if (pick_.connected_subchannel != nullptr) { + pick_.connected_subchannel.reset(); + } + for (size_t i = 0; i < GRPC_CONTEXT_COUNT; ++i) { + if (pick_.subchannel_call_context[i].destroy != nullptr) { + pick_.subchannel_call_context[i].destroy( + pick_.subchannel_call_context[i].value); + } + } +} + +// Invoked once resolver results are available. +void RequestRouter::Request::ProcessServiceConfigAndStartLbPickLocked() { + // Get service config data if needed. + if (!apply_service_config_(apply_service_config_user_data_)) return; + // Start LB pick. + StartLbPickLocked(); +} + +void RequestRouter::Request::MaybeAddCallToInterestedPartiesLocked() { + if (!pollent_added_to_interested_parties_) { + pollent_added_to_interested_parties_ = true; + grpc_polling_entity_add_to_pollset_set( + pollent_, request_router_->interested_parties_); + } +} + +void RequestRouter::Request::MaybeRemoveCallFromInterestedPartiesLocked() { + if (pollent_added_to_interested_parties_) { + pollent_added_to_interested_parties_ = false; + grpc_polling_entity_del_from_pollset_set( + pollent_, request_router_->interested_parties_); + } +} + +// Starts a pick on the LB policy. +void RequestRouter::Request::StartLbPickLocked() { + if (request_router_->tracer_->enabled()) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: starting pick on lb_policy=%p", + request_router_, this, request_router_->lb_policy_.get()); + } + GRPC_CLOSURE_INIT(&on_pick_done_, &LbPickDoneLocked, this, + grpc_combiner_scheduler(request_router_->combiner_)); + pick_.on_complete = &on_pick_done_; + GRPC_CALL_STACK_REF(owning_call_, "pick_callback"); + grpc_error* error = GRPC_ERROR_NONE; + const bool pick_done = + request_router_->lb_policy_->PickLocked(&pick_, &error); + if (pick_done) { + // Pick completed synchronously. + if (request_router_->tracer_->enabled()) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: pick completed synchronously", + request_router_, this); + } + GRPC_CLOSURE_RUN(on_route_done_, error); + GRPC_CALL_STACK_UNREF(owning_call_, "pick_callback"); + } else { + // Pick will be returned asynchronously. + // Add the request's polling entity to the request_router's + // interested_parties, so that the I/O of the LB policy can be done + // under it. It will be removed in LbPickDoneLocked(). + MaybeAddCallToInterestedPartiesLocked(); + // Request notification on call cancellation. + // We allocate a separate object to track cancellation, since the + // cancellation closure might still be pending when we need to reuse + // the memory in which this Request object is stored for a subsequent + // retry attempt. + pick_canceller_ = New<AsyncPickCanceller>(this); + } +} + +// Callback invoked by LoadBalancingPolicy::PickLocked() for async picks. +// Unrefs the LB policy and invokes on_route_done_. +void RequestRouter::Request::LbPickDoneLocked(void* arg, grpc_error* error) { + Request* self = static_cast<Request*>(arg); + RequestRouter* request_router = self->request_router_; + if (request_router->tracer_->enabled()) { + gpr_log(GPR_INFO, + "request_router=%p request=%p: pick completed asynchronously", + request_router, self); + } + self->MaybeRemoveCallFromInterestedPartiesLocked(); + if (self->pick_canceller_ != nullptr) { + self->pick_canceller_->MarkFinishedLocked(); + } + GRPC_CLOSURE_RUN(self->on_route_done_, GRPC_ERROR_REF(error)); + GRPC_CALL_STACK_UNREF(self->owning_call_, "pick_callback"); +} + +// +// RequestRouter::LbConnectivityWatcher +// + +class RequestRouter::LbConnectivityWatcher { + public: + LbConnectivityWatcher(RequestRouter* request_router, + grpc_connectivity_state state, + LoadBalancingPolicy* lb_policy, + grpc_channel_stack* owning_stack, + grpc_combiner* combiner) + : request_router_(request_router), + state_(state), + lb_policy_(lb_policy), + owning_stack_(owning_stack) { + GRPC_CHANNEL_STACK_REF(owning_stack_, "LbConnectivityWatcher"); + GRPC_CLOSURE_INIT(&on_changed_, &OnLbPolicyStateChangedLocked, this, + grpc_combiner_scheduler(combiner)); + lb_policy_->NotifyOnStateChangeLocked(&state_, &on_changed_); + } + + ~LbConnectivityWatcher() { + GRPC_CHANNEL_STACK_UNREF(owning_stack_, "LbConnectivityWatcher"); + } + + private: + static void OnLbPolicyStateChangedLocked(void* arg, grpc_error* error) { + LbConnectivityWatcher* self = static_cast<LbConnectivityWatcher*>(arg); + // If the notification is not for the current policy, we're stale, + // so delete ourselves. + if (self->lb_policy_ != self->request_router_->lb_policy_.get()) { + Delete(self); + return; + } + // Otherwise, process notification. + if (self->request_router_->tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: lb_policy=%p state changed to %s", + self->request_router_, self->lb_policy_, + grpc_connectivity_state_name(self->state_)); + } + self->request_router_->SetConnectivityStateLocked( + self->state_, GRPC_ERROR_REF(error), "lb_changed"); + // If shutting down, terminate watch. + if (self->state_ == GRPC_CHANNEL_SHUTDOWN) { + Delete(self); + return; + } + // Renew watch. + self->lb_policy_->NotifyOnStateChangeLocked(&self->state_, + &self->on_changed_); + } + + RequestRouter* request_router_; + grpc_connectivity_state state_; + // LB policy address. No ref held, so not safe to dereference unless + // it happens to match request_router->lb_policy_. + LoadBalancingPolicy* lb_policy_; + grpc_channel_stack* owning_stack_; + grpc_closure on_changed_; +}; + +// +// RequestRounter::ReresolutionRequestHandler +// + +class RequestRouter::ReresolutionRequestHandler { + public: + ReresolutionRequestHandler(RequestRouter* request_router, + LoadBalancingPolicy* lb_policy, + grpc_channel_stack* owning_stack, + grpc_combiner* combiner) + : request_router_(request_router), + lb_policy_(lb_policy), + owning_stack_(owning_stack) { + GRPC_CHANNEL_STACK_REF(owning_stack_, "ReresolutionRequestHandler"); + GRPC_CLOSURE_INIT(&closure_, &OnRequestReresolutionLocked, this, + grpc_combiner_scheduler(combiner)); + lb_policy_->SetReresolutionClosureLocked(&closure_); + } + + private: + static void OnRequestReresolutionLocked(void* arg, grpc_error* error) { + ReresolutionRequestHandler* self = + static_cast<ReresolutionRequestHandler*>(arg); + RequestRouter* request_router = self->request_router_; + // If this invocation is for a stale LB policy, treat it as an LB shutdown + // signal. + if (self->lb_policy_ != request_router->lb_policy_.get() || + error != GRPC_ERROR_NONE || request_router->resolver_ == nullptr) { + GRPC_CHANNEL_STACK_UNREF(request_router->owning_stack_, + "ReresolutionRequestHandler"); + Delete(self); + return; + } + if (request_router->tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: started name re-resolving", + request_router); + } + request_router->resolver_->RequestReresolutionLocked(); + // Give back the closure to the LB policy. + self->lb_policy_->SetReresolutionClosureLocked(&self->closure_); + } + + RequestRouter* request_router_; + // LB policy address. No ref held, so not safe to dereference unless + // it happens to match request_router->lb_policy_. + LoadBalancingPolicy* lb_policy_; + grpc_channel_stack* owning_stack_; + grpc_closure closure_; +}; + +// +// RequestRouter +// + +RequestRouter::RequestRouter( + grpc_channel_stack* owning_stack, grpc_combiner* combiner, + grpc_client_channel_factory* client_channel_factory, + grpc_pollset_set* interested_parties, TraceFlag* tracer, + ProcessResolverResultCallback process_resolver_result, + void* process_resolver_result_user_data, const char* target_uri, + const grpc_channel_args* args, grpc_error** error) + : owning_stack_(owning_stack), + combiner_(combiner), + client_channel_factory_(client_channel_factory), + interested_parties_(interested_parties), + tracer_(tracer), + process_resolver_result_(process_resolver_result), + process_resolver_result_user_data_(process_resolver_result_user_data) { + GRPC_CLOSURE_INIT(&on_resolver_result_changed_, + &RequestRouter::OnResolverResultChangedLocked, this, + grpc_combiner_scheduler(combiner)); + grpc_connectivity_state_init(&state_tracker_, GRPC_CHANNEL_IDLE, + "request_router"); + grpc_channel_args* new_args = nullptr; + if (process_resolver_result == nullptr) { + grpc_arg arg = grpc_channel_arg_integer_create( + const_cast<char*>(GRPC_ARG_SERVICE_CONFIG_DISABLE_RESOLUTION), 0); + new_args = grpc_channel_args_copy_and_add(args, &arg, 1); + } + resolver_ = ResolverRegistry::CreateResolver( + target_uri, (new_args == nullptr ? args : new_args), interested_parties_, + combiner_); + grpc_channel_args_destroy(new_args); + if (resolver_ == nullptr) { + *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("resolver creation failed"); + } +} + +RequestRouter::~RequestRouter() { + if (resolver_ != nullptr) { + // The only way we can get here is if we never started resolving, + // because we take a ref to the channel stack when we start + // resolving and do not release it until the resolver callback is + // invoked after the resolver shuts down. + resolver_.reset(); + } + if (lb_policy_ != nullptr) { + grpc_pollset_set_del_pollset_set(lb_policy_->interested_parties(), + interested_parties_); + lb_policy_.reset(); + } + if (client_channel_factory_ != nullptr) { + grpc_client_channel_factory_unref(client_channel_factory_); + } + grpc_connectivity_state_destroy(&state_tracker_); +} + +namespace { + +const char* GetChannelConnectivityStateChangeString( + grpc_connectivity_state state) { + switch (state) { + case GRPC_CHANNEL_IDLE: + return "Channel state change to IDLE"; + case GRPC_CHANNEL_CONNECTING: + return "Channel state change to CONNECTING"; + case GRPC_CHANNEL_READY: + return "Channel state change to READY"; + case GRPC_CHANNEL_TRANSIENT_FAILURE: + return "Channel state change to TRANSIENT_FAILURE"; + case GRPC_CHANNEL_SHUTDOWN: + return "Channel state change to SHUTDOWN"; + } + GPR_UNREACHABLE_CODE(return "UNKNOWN"); +} + +} // namespace + +void RequestRouter::SetConnectivityStateLocked(grpc_connectivity_state state, + grpc_error* error, + const char* reason) { + if (lb_policy_ != nullptr) { + if (state == GRPC_CHANNEL_TRANSIENT_FAILURE) { + // Cancel picks with wait_for_ready=false. + lb_policy_->CancelMatchingPicksLocked( + /* mask= */ GRPC_INITIAL_METADATA_WAIT_FOR_READY, + /* check= */ 0, GRPC_ERROR_REF(error)); + } else if (state == GRPC_CHANNEL_SHUTDOWN) { + // Cancel all picks. + lb_policy_->CancelMatchingPicksLocked(/* mask= */ 0, /* check= */ 0, + GRPC_ERROR_REF(error)); + } + } + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: setting connectivity state to %s", + this, grpc_connectivity_state_name(state)); + } + if (channelz_node_ != nullptr) { + channelz_node_->AddTraceEvent( + channelz::ChannelTrace::Severity::Info, + grpc_slice_from_static_string( + GetChannelConnectivityStateChangeString(state))); + } + grpc_connectivity_state_set(&state_tracker_, state, error, reason); +} + +void RequestRouter::StartResolvingLocked() { + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: starting name resolution", this); + } + GPR_ASSERT(!started_resolving_); + started_resolving_ = true; + GRPC_CHANNEL_STACK_REF(owning_stack_, "resolver"); + resolver_->NextLocked(&resolver_result_, &on_resolver_result_changed_); +} + +// Invoked from the resolver NextLocked() callback when the resolver +// is shutting down. +void RequestRouter::OnResolverShutdownLocked(grpc_error* error) { + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: shutting down", this); + } + if (lb_policy_ != nullptr) { + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: shutting down lb_policy=%p", this, + lb_policy_.get()); + } + grpc_pollset_set_del_pollset_set(lb_policy_->interested_parties(), + interested_parties_); + lb_policy_.reset(); + } + if (resolver_ != nullptr) { + // This should never happen; it can only be triggered by a resolver + // implementation spotaneously deciding to report shutdown without + // being orphaned. This code is included just to be defensive. + if (tracer_->enabled()) { + gpr_log(GPR_INFO, + "request_router=%p: spontaneous shutdown from resolver %p", this, + resolver_.get()); + } + resolver_.reset(); + SetConnectivityStateLocked(GRPC_CHANNEL_SHUTDOWN, + GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( + "Resolver spontaneous shutdown", &error, 1), + "resolver_spontaneous_shutdown"); + } + grpc_closure_list_fail_all(&waiting_for_resolver_result_closures_, + GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING( + "Channel disconnected", &error, 1)); + GRPC_CLOSURE_LIST_SCHED(&waiting_for_resolver_result_closures_); + GRPC_CHANNEL_STACK_UNREF(owning_stack_, "resolver"); + grpc_channel_args_destroy(resolver_result_); + resolver_result_ = nullptr; + GRPC_ERROR_UNREF(error); +} + +// Creates a new LB policy, replacing any previous one. +// If the new policy is created successfully, sets *connectivity_state and +// *connectivity_error to its initial connectivity state; otherwise, +// leaves them unchanged. +void RequestRouter::CreateNewLbPolicyLocked( + const char* lb_policy_name, grpc_json* lb_config, + grpc_connectivity_state* connectivity_state, + grpc_error** connectivity_error, TraceStringVector* trace_strings) { + LoadBalancingPolicy::Args lb_policy_args; + lb_policy_args.combiner = combiner_; + lb_policy_args.client_channel_factory = client_channel_factory_; + lb_policy_args.args = resolver_result_; + lb_policy_args.lb_config = lb_config; + OrphanablePtr<LoadBalancingPolicy> new_lb_policy = + LoadBalancingPolicyRegistry::CreateLoadBalancingPolicy(lb_policy_name, + lb_policy_args); + if (GPR_UNLIKELY(new_lb_policy == nullptr)) { + gpr_log(GPR_ERROR, "could not create LB policy \"%s\"", lb_policy_name); + if (channelz_node_ != nullptr) { + char* str; + gpr_asprintf(&str, "Could not create LB policy \'%s\'", lb_policy_name); + trace_strings->push_back(str); + } + } else { + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: created new LB policy \"%s\" (%p)", + this, lb_policy_name, new_lb_policy.get()); + } + if (channelz_node_ != nullptr) { + char* str; + gpr_asprintf(&str, "Created new LB policy \'%s\'", lb_policy_name); + trace_strings->push_back(str); + } + // Swap out the LB policy and update the fds in interested_parties_. + if (lb_policy_ != nullptr) { + if (tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: shutting down lb_policy=%p", this, + lb_policy_.get()); + } + grpc_pollset_set_del_pollset_set(lb_policy_->interested_parties(), + interested_parties_); + lb_policy_->HandOffPendingPicksLocked(new_lb_policy.get()); + } + lb_policy_ = std::move(new_lb_policy); + grpc_pollset_set_add_pollset_set(lb_policy_->interested_parties(), + interested_parties_); + // Create re-resolution request handler for the new LB policy. It + // will delete itself when no longer needed. + New<ReresolutionRequestHandler>(this, lb_policy_.get(), owning_stack_, + combiner_); + // Get the new LB policy's initial connectivity state and start a + // connectivity watch. + GRPC_ERROR_UNREF(*connectivity_error); + *connectivity_state = + lb_policy_->CheckConnectivityLocked(connectivity_error); + if (exit_idle_when_lb_policy_arrives_) { + lb_policy_->ExitIdleLocked(); + exit_idle_when_lb_policy_arrives_ = false; + } + // Create new watcher. It will delete itself when done. + New<LbConnectivityWatcher>(this, *connectivity_state, lb_policy_.get(), + owning_stack_, combiner_); + } +} + +void RequestRouter::MaybeAddTraceMessagesForAddressChangesLocked( + TraceStringVector* trace_strings) { + const ServerAddressList* addresses = + FindServerAddressListChannelArg(resolver_result_); + const bool resolution_contains_addresses = + addresses != nullptr && addresses->size() > 0; + if (!resolution_contains_addresses && + previous_resolution_contained_addresses_) { + trace_strings->push_back(gpr_strdup("Address list became empty")); + } else if (resolution_contains_addresses && + !previous_resolution_contained_addresses_) { + trace_strings->push_back(gpr_strdup("Address list became non-empty")); + } + previous_resolution_contained_addresses_ = resolution_contains_addresses; +} + +void RequestRouter::ConcatenateAndAddChannelTraceLocked( + TraceStringVector* trace_strings) const { + if (!trace_strings->empty()) { + gpr_strvec v; + gpr_strvec_init(&v); + gpr_strvec_add(&v, gpr_strdup("Resolution event: ")); + bool is_first = 1; + for (size_t i = 0; i < trace_strings->size(); ++i) { + if (!is_first) gpr_strvec_add(&v, gpr_strdup(", ")); + is_first = false; + gpr_strvec_add(&v, (*trace_strings)[i]); + } + char* flat; + size_t flat_len = 0; + flat = gpr_strvec_flatten(&v, &flat_len); + channelz_node_->AddTraceEvent( + grpc_core::channelz::ChannelTrace::Severity::Info, + grpc_slice_new(flat, flat_len, gpr_free)); + gpr_strvec_destroy(&v); + } +} + +// Callback invoked when a resolver result is available. +void RequestRouter::OnResolverResultChangedLocked(void* arg, + grpc_error* error) { + RequestRouter* self = static_cast<RequestRouter*>(arg); + if (self->tracer_->enabled()) { + const char* disposition = + self->resolver_result_ != nullptr + ? "" + : (error == GRPC_ERROR_NONE ? " (transient error)" + : " (resolver shutdown)"); + gpr_log(GPR_INFO, + "request_router=%p: got resolver result: resolver_result=%p " + "error=%s%s", + self, self->resolver_result_, grpc_error_string(error), + disposition); + } + // Handle shutdown. + if (error != GRPC_ERROR_NONE || self->resolver_ == nullptr) { + self->OnResolverShutdownLocked(GRPC_ERROR_REF(error)); + return; + } + // Data used to set the channel's connectivity state. + bool set_connectivity_state = true; + // We only want to trace the address resolution in the follow cases: + // (a) Address resolution resulted in service config change. + // (b) Address resolution that causes number of backends to go from + // zero to non-zero. + // (c) Address resolution that causes number of backends to go from + // non-zero to zero. + // (d) Address resolution that causes a new LB policy to be created. + // + // we track a list of strings to eventually be concatenated and traced. + TraceStringVector trace_strings; + grpc_connectivity_state connectivity_state = GRPC_CHANNEL_TRANSIENT_FAILURE; + grpc_error* connectivity_error = + GRPC_ERROR_CREATE_FROM_STATIC_STRING("No load balancing policy"); + // resolver_result_ will be null in the case of a transient + // resolution error. In that case, we don't have any new result to + // process, which means that we keep using the previous result (if any). + if (self->resolver_result_ == nullptr) { + if (self->tracer_->enabled()) { + gpr_log(GPR_INFO, "request_router=%p: resolver transient failure", self); + } + // Don't override connectivity state if we already have an LB policy. + if (self->lb_policy_ != nullptr) set_connectivity_state = false; + } else { + // Parse the resolver result. + const char* lb_policy_name = nullptr; + grpc_json* lb_policy_config = nullptr; + const bool service_config_changed = self->process_resolver_result_( + self->process_resolver_result_user_data_, *self->resolver_result_, + &lb_policy_name, &lb_policy_config); + GPR_ASSERT(lb_policy_name != nullptr); + // Check to see if we're already using the right LB policy. + const bool lb_policy_name_changed = + self->lb_policy_ == nullptr || + strcmp(self->lb_policy_->name(), lb_policy_name) != 0; + if (self->lb_policy_ != nullptr && !lb_policy_name_changed) { + // Continue using the same LB policy. Update with new addresses. + if (self->tracer_->enabled()) { + gpr_log(GPR_INFO, + "request_router=%p: updating existing LB policy \"%s\" (%p)", + self, lb_policy_name, self->lb_policy_.get()); + } + self->lb_policy_->UpdateLocked(*self->resolver_result_, lb_policy_config); + // No need to set the channel's connectivity state; the existing + // watch on the LB policy will take care of that. + set_connectivity_state = false; + } else { + // Instantiate new LB policy. + self->CreateNewLbPolicyLocked(lb_policy_name, lb_policy_config, + &connectivity_state, &connectivity_error, + &trace_strings); + } + // Add channel trace event. + if (self->channelz_node_ != nullptr) { + if (service_config_changed) { + // TODO(ncteisen): might be worth somehow including a snippet of the + // config in the trace, at the risk of bloating the trace logs. + trace_strings.push_back(gpr_strdup("Service config changed")); + } + self->MaybeAddTraceMessagesForAddressChangesLocked(&trace_strings); + self->ConcatenateAndAddChannelTraceLocked(&trace_strings); + } + // Clean up. + grpc_channel_args_destroy(self->resolver_result_); + self->resolver_result_ = nullptr; + } + // Set the channel's connectivity state if needed. + if (set_connectivity_state) { + self->SetConnectivityStateLocked(connectivity_state, connectivity_error, + "resolver_result"); + } else { + GRPC_ERROR_UNREF(connectivity_error); + } + // Invoke closures that were waiting for results and renew the watch. + GRPC_CLOSURE_LIST_SCHED(&self->waiting_for_resolver_result_closures_); + self->resolver_->NextLocked(&self->resolver_result_, + &self->on_resolver_result_changed_); +} + +void RequestRouter::RouteCallLocked(Request* request) { + GPR_ASSERT(request->pick_.connected_subchannel == nullptr); + request->request_router_ = this; + if (lb_policy_ != nullptr) { + // We already have resolver results, so process the service config + // and start an LB pick. + request->ProcessServiceConfigAndStartLbPickLocked(); + } else if (resolver_ == nullptr) { + GRPC_CLOSURE_RUN(request->on_route_done_, + GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected")); + } else { + // We do not yet have an LB policy, so wait for a resolver result. + if (!started_resolving_) { + StartResolvingLocked(); + } + // Create a new waiter, which will delete itself when done. + New<Request::ResolverResultWaiter>(request); + // Add the request's polling entity to the request_router's + // interested_parties, so that the I/O of the resolver can be done + // under it. It will be removed in LbPickDoneLocked(). + request->MaybeAddCallToInterestedPartiesLocked(); + } +} + +void RequestRouter::ShutdownLocked(grpc_error* error) { + if (resolver_ != nullptr) { + SetConnectivityStateLocked(GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(error), + "disconnect"); + resolver_.reset(); + if (!started_resolving_) { + grpc_closure_list_fail_all(&waiting_for_resolver_result_closures_, + GRPC_ERROR_REF(error)); + GRPC_CLOSURE_LIST_SCHED(&waiting_for_resolver_result_closures_); + } + if (lb_policy_ != nullptr) { + grpc_pollset_set_del_pollset_set(lb_policy_->interested_parties(), + interested_parties_); + lb_policy_.reset(); + } + } + GRPC_ERROR_UNREF(error); +} + +grpc_connectivity_state RequestRouter::GetConnectivityState() { + return grpc_connectivity_state_check(&state_tracker_); +} + +void RequestRouter::NotifyOnConnectivityStateChange( + grpc_connectivity_state* state, grpc_closure* closure) { + grpc_connectivity_state_notify_on_state_change(&state_tracker_, state, + closure); +} + +void RequestRouter::ExitIdleLocked() { + if (lb_policy_ != nullptr) { + lb_policy_->ExitIdleLocked(); + } else { + exit_idle_when_lb_policy_arrives_ = true; + if (!started_resolving_ && resolver_ != nullptr) { + StartResolvingLocked(); + } + } +} + +void RequestRouter::ResetConnectionBackoffLocked() { + if (resolver_ != nullptr) { + resolver_->ResetBackoffLocked(); + resolver_->RequestReresolutionLocked(); + } + if (lb_policy_ != nullptr) { + lb_policy_->ResetBackoffLocked(); + } +} + +} // namespace grpc_core diff --git a/src/core/ext/filters/client_channel/request_routing.h b/src/core/ext/filters/client_channel/request_routing.h new file mode 100644 index 0000000000..0c671229c8 --- /dev/null +++ b/src/core/ext/filters/client_channel/request_routing.h @@ -0,0 +1,177 @@ +/* + * + * Copyright 2018 gRPC authors. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + */ + +#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_REQUEST_ROUTING_H +#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_REQUEST_ROUTING_H + +#include <grpc/support/port_platform.h> + +#include "src/core/ext/filters/client_channel/client_channel_channelz.h" +#include "src/core/ext/filters/client_channel/client_channel_factory.h" +#include "src/core/ext/filters/client_channel/lb_policy.h" +#include "src/core/ext/filters/client_channel/resolver.h" +#include "src/core/lib/channel/channel_args.h" +#include "src/core/lib/channel/channel_stack.h" +#include "src/core/lib/debug/trace.h" +#include "src/core/lib/gprpp/inlined_vector.h" +#include "src/core/lib/gprpp/orphanable.h" +#include "src/core/lib/iomgr/call_combiner.h" +#include "src/core/lib/iomgr/closure.h" +#include "src/core/lib/iomgr/polling_entity.h" +#include "src/core/lib/iomgr/pollset_set.h" +#include "src/core/lib/transport/connectivity_state.h" +#include "src/core/lib/transport/metadata_batch.h" + +namespace grpc_core { + +class RequestRouter { + public: + class Request { + public: + // Synchronous callback that applies the service config to a call. + // Returns false if the call should be failed. + typedef bool (*ApplyServiceConfigCallback)(void* user_data); + + Request(grpc_call_stack* owning_call, grpc_call_combiner* call_combiner, + grpc_polling_entity* pollent, + grpc_metadata_batch* send_initial_metadata, + uint32_t* send_initial_metadata_flags, + ApplyServiceConfigCallback apply_service_config, + void* apply_service_config_user_data, grpc_closure* on_route_done); + + ~Request(); + + // TODO(roth): It seems a bit ugly to expose this member in a + // non-const way. Find a better API to avoid this. + LoadBalancingPolicy::PickState* pick() { return &pick_; } + + private: + friend class RequestRouter; + + class ResolverResultWaiter; + class AsyncPickCanceller; + + void ProcessServiceConfigAndStartLbPickLocked(); + void StartLbPickLocked(); + static void LbPickDoneLocked(void* arg, grpc_error* error); + + void MaybeAddCallToInterestedPartiesLocked(); + void MaybeRemoveCallFromInterestedPartiesLocked(); + + // Populated by caller. + grpc_call_stack* owning_call_; + grpc_call_combiner* call_combiner_; + grpc_polling_entity* pollent_; + ApplyServiceConfigCallback apply_service_config_; + void* apply_service_config_user_data_; + grpc_closure* on_route_done_; + LoadBalancingPolicy::PickState pick_; + + // Internal state. + RequestRouter* request_router_ = nullptr; + bool pollent_added_to_interested_parties_ = false; + grpc_closure on_pick_done_; + AsyncPickCanceller* pick_canceller_ = nullptr; + }; + + // Synchronous callback that takes the service config JSON string and + // LB policy name. + // Returns true if the service config has changed since the last result. + typedef bool (*ProcessResolverResultCallback)(void* user_data, + const grpc_channel_args& args, + const char** lb_policy_name, + grpc_json** lb_policy_config); + + RequestRouter(grpc_channel_stack* owning_stack, grpc_combiner* combiner, + grpc_client_channel_factory* client_channel_factory, + grpc_pollset_set* interested_parties, TraceFlag* tracer, + ProcessResolverResultCallback process_resolver_result, + void* process_resolver_result_user_data, const char* target_uri, + const grpc_channel_args* args, grpc_error** error); + + ~RequestRouter(); + + void set_channelz_node(channelz::ClientChannelNode* channelz_node) { + channelz_node_ = channelz_node; + } + + void RouteCallLocked(Request* request); + + // TODO(roth): Add methods to cancel picks. + + void ShutdownLocked(grpc_error* error); + + void ExitIdleLocked(); + void ResetConnectionBackoffLocked(); + + grpc_connectivity_state GetConnectivityState(); + void NotifyOnConnectivityStateChange(grpc_connectivity_state* state, + grpc_closure* closure); + + LoadBalancingPolicy* lb_policy() const { return lb_policy_.get(); } + + private: + using TraceStringVector = grpc_core::InlinedVector<char*, 3>; + + class ReresolutionRequestHandler; + class LbConnectivityWatcher; + + void StartResolvingLocked(); + void OnResolverShutdownLocked(grpc_error* error); + void CreateNewLbPolicyLocked(const char* lb_policy_name, grpc_json* lb_config, + grpc_connectivity_state* connectivity_state, + grpc_error** connectivity_error, + TraceStringVector* trace_strings); + void MaybeAddTraceMessagesForAddressChangesLocked( + TraceStringVector* trace_strings); + void ConcatenateAndAddChannelTraceLocked( + TraceStringVector* trace_strings) const; + static void OnResolverResultChangedLocked(void* arg, grpc_error* error); + + void SetConnectivityStateLocked(grpc_connectivity_state state, + grpc_error* error, const char* reason); + + // Passed in from caller at construction time. + grpc_channel_stack* owning_stack_; + grpc_combiner* combiner_; + grpc_client_channel_factory* client_channel_factory_; + grpc_pollset_set* interested_parties_; + TraceFlag* tracer_; + + channelz::ClientChannelNode* channelz_node_ = nullptr; + + // Resolver and associated state. + OrphanablePtr<Resolver> resolver_; + ProcessResolverResultCallback process_resolver_result_; + void* process_resolver_result_user_data_; + bool started_resolving_ = false; + grpc_channel_args* resolver_result_ = nullptr; + bool previous_resolution_contained_addresses_ = false; + grpc_closure_list waiting_for_resolver_result_closures_; + grpc_closure on_resolver_result_changed_; + + // LB policy and associated state. + OrphanablePtr<LoadBalancingPolicy> lb_policy_; + bool exit_idle_when_lb_policy_arrives_ = false; + + grpc_connectivity_state_tracker state_tracker_; +}; + +} // namespace grpc_core + +#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_REQUEST_ROUTING_H */ diff --git a/src/core/ext/filters/client_channel/resolver_result_parsing.cc b/src/core/ext/filters/client_channel/resolver_result_parsing.cc index 22b06db45c..9a0122e8ec 100644 --- a/src/core/ext/filters/client_channel/resolver_result_parsing.cc +++ b/src/core/ext/filters/client_channel/resolver_result_parsing.cc @@ -43,16 +43,16 @@ namespace grpc_core { namespace internal { ProcessedResolverResult::ProcessedResolverResult( - const grpc_channel_args* resolver_result, bool parse_retry) { + const grpc_channel_args& resolver_result, bool parse_retry) { ProcessServiceConfig(resolver_result, parse_retry); // If no LB config was found above, just find the LB policy name then. if (lb_policy_name_ == nullptr) ProcessLbPolicyName(resolver_result); } void ProcessedResolverResult::ProcessServiceConfig( - const grpc_channel_args* resolver_result, bool parse_retry) { + const grpc_channel_args& resolver_result, bool parse_retry) { const grpc_arg* channel_arg = - grpc_channel_args_find(resolver_result, GRPC_ARG_SERVICE_CONFIG); + grpc_channel_args_find(&resolver_result, GRPC_ARG_SERVICE_CONFIG); const char* service_config_json = grpc_channel_arg_get_string(channel_arg); if (service_config_json != nullptr) { service_config_json_.reset(gpr_strdup(service_config_json)); @@ -60,7 +60,7 @@ void ProcessedResolverResult::ProcessServiceConfig( if (service_config_ != nullptr) { if (parse_retry) { channel_arg = - grpc_channel_args_find(resolver_result, GRPC_ARG_SERVER_URI); + grpc_channel_args_find(&resolver_result, GRPC_ARG_SERVER_URI); const char* server_uri = grpc_channel_arg_get_string(channel_arg); GPR_ASSERT(server_uri != nullptr); grpc_uri* uri = grpc_uri_parse(server_uri, true); @@ -78,7 +78,7 @@ void ProcessedResolverResult::ProcessServiceConfig( } void ProcessedResolverResult::ProcessLbPolicyName( - const grpc_channel_args* resolver_result) { + const grpc_channel_args& resolver_result) { // Prefer the LB policy name found in the service config. Note that this is // checking the deprecated loadBalancingPolicy field, rather than the new // loadBalancingConfig field. @@ -96,13 +96,13 @@ void ProcessedResolverResult::ProcessLbPolicyName( // Otherwise, find the LB policy name set by the client API. if (lb_policy_name_ == nullptr) { const grpc_arg* channel_arg = - grpc_channel_args_find(resolver_result, GRPC_ARG_LB_POLICY_NAME); + grpc_channel_args_find(&resolver_result, GRPC_ARG_LB_POLICY_NAME); lb_policy_name_.reset(gpr_strdup(grpc_channel_arg_get_string(channel_arg))); } // Special case: If at least one balancer address is present, we use // the grpclb policy, regardless of what the resolver has returned. const ServerAddressList* addresses = - FindServerAddressListChannelArg(resolver_result); + FindServerAddressListChannelArg(&resolver_result); if (addresses != nullptr) { bool found_balancer_address = false; for (size_t i = 0; i < addresses->size(); ++i) { diff --git a/src/core/ext/filters/client_channel/resolver_result_parsing.h b/src/core/ext/filters/client_channel/resolver_result_parsing.h index f1fb7406bc..98a9d26c46 100644 --- a/src/core/ext/filters/client_channel/resolver_result_parsing.h +++ b/src/core/ext/filters/client_channel/resolver_result_parsing.h @@ -36,8 +36,7 @@ namespace internal { class ClientChannelMethodParams; // A table mapping from a method name to its method parameters. -typedef grpc_core::SliceHashTable< - grpc_core::RefCountedPtr<ClientChannelMethodParams>> +typedef SliceHashTable<RefCountedPtr<ClientChannelMethodParams>> ClientChannelMethodParamsTable; // A container of processed fields from the resolver result. Simplifies the @@ -47,33 +46,30 @@ class ProcessedResolverResult { // Processes the resolver result and populates the relative members // for later consumption. Tries to parse retry parameters only if parse_retry // is true. - ProcessedResolverResult(const grpc_channel_args* resolver_result, + ProcessedResolverResult(const grpc_channel_args& resolver_result, bool parse_retry); // Getters. Any managed object's ownership is transferred. - grpc_core::UniquePtr<char> service_config_json() { + UniquePtr<char> service_config_json() { return std::move(service_config_json_); } - grpc_core::RefCountedPtr<ServerRetryThrottleData> retry_throttle_data() { + RefCountedPtr<ServerRetryThrottleData> retry_throttle_data() { return std::move(retry_throttle_data_); } - grpc_core::RefCountedPtr<ClientChannelMethodParamsTable> - method_params_table() { + RefCountedPtr<ClientChannelMethodParamsTable> method_params_table() { return std::move(method_params_table_); } - grpc_core::UniquePtr<char> lb_policy_name() { - return std::move(lb_policy_name_); - } + UniquePtr<char> lb_policy_name() { return std::move(lb_policy_name_); } grpc_json* lb_policy_config() { return lb_policy_config_; } private: // Finds the service config; extracts LB config and (maybe) retry throttle // params from it. - void ProcessServiceConfig(const grpc_channel_args* resolver_result, + void ProcessServiceConfig(const grpc_channel_args& resolver_result, bool parse_retry); // Finds the LB policy name (when no LB config was found). - void ProcessLbPolicyName(const grpc_channel_args* resolver_result); + void ProcessLbPolicyName(const grpc_channel_args& resolver_result); // Parses the service config. Intended to be used by // ServiceConfig::ParseGlobalParams. @@ -85,16 +81,16 @@ class ProcessedResolverResult { void ParseRetryThrottleParamsFromServiceConfig(const grpc_json* field); // Service config. - grpc_core::UniquePtr<char> service_config_json_; - grpc_core::UniquePtr<grpc_core::ServiceConfig> service_config_; + UniquePtr<char> service_config_json_; + UniquePtr<grpc_core::ServiceConfig> service_config_; // LB policy. grpc_json* lb_policy_config_ = nullptr; - grpc_core::UniquePtr<char> lb_policy_name_; + UniquePtr<char> lb_policy_name_; // Retry throttle data. char* server_name_ = nullptr; - grpc_core::RefCountedPtr<ServerRetryThrottleData> retry_throttle_data_; + RefCountedPtr<ServerRetryThrottleData> retry_throttle_data_; // Method params table. - grpc_core::RefCountedPtr<ClientChannelMethodParamsTable> method_params_table_; + RefCountedPtr<ClientChannelMethodParamsTable> method_params_table_; }; // The parameters of a method. diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py index c6ca970bee..6a1fd676ca 100644 --- a/src/python/grpcio/grpc_core_dependencies.py +++ b/src/python/grpcio/grpc_core_dependencies.py @@ -326,6 +326,7 @@ CORE_SOURCE_FILES = [ 'src/core/ext/filters/client_channel/parse_address.cc', 'src/core/ext/filters/client_channel/proxy_mapper.cc', 'src/core/ext/filters/client_channel/proxy_mapper_registry.cc', + 'src/core/ext/filters/client_channel/request_routing.cc', 'src/core/ext/filters/client_channel/resolver.cc', 'src/core/ext/filters/client_channel/resolver_registry.cc', 'src/core/ext/filters/client_channel/resolver_result_parsing.cc', diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal index 5011e19b03..ba2eaecafd 100644 --- a/tools/doxygen/Doxyfile.core.internal +++ b/tools/doxygen/Doxyfile.core.internal @@ -932,6 +932,8 @@ src/core/ext/filters/client_channel/proxy_mapper.cc \ src/core/ext/filters/client_channel/proxy_mapper.h \ src/core/ext/filters/client_channel/proxy_mapper_registry.cc \ src/core/ext/filters/client_channel/proxy_mapper_registry.h \ +src/core/ext/filters/client_channel/request_routing.cc \ +src/core/ext/filters/client_channel/request_routing.h \ src/core/ext/filters/client_channel/resolver.cc \ src/core/ext/filters/client_channel/resolver.h \ src/core/ext/filters/client_channel/resolver/README.md \ diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json index 46e5d54c85..336d499be9 100644 --- a/tools/run_tests/generated/sources_and_headers.json +++ b/tools/run_tests/generated/sources_and_headers.json @@ -9840,6 +9840,7 @@ "src/core/ext/filters/client_channel/parse_address.h", "src/core/ext/filters/client_channel/proxy_mapper.h", "src/core/ext/filters/client_channel/proxy_mapper_registry.h", + "src/core/ext/filters/client_channel/request_routing.h", "src/core/ext/filters/client_channel/resolver.h", "src/core/ext/filters/client_channel/resolver_factory.h", "src/core/ext/filters/client_channel/resolver_registry.h", @@ -9882,6 +9883,8 @@ "src/core/ext/filters/client_channel/proxy_mapper.h", "src/core/ext/filters/client_channel/proxy_mapper_registry.cc", "src/core/ext/filters/client_channel/proxy_mapper_registry.h", + "src/core/ext/filters/client_channel/request_routing.cc", + "src/core/ext/filters/client_channel/request_routing.h", "src/core/ext/filters/client_channel/resolver.cc", "src/core/ext/filters/client_channel/resolver.h", "src/core/ext/filters/client_channel/resolver_factory.h", |