/* * * Copyright 2015, Google Inc. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are * met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * Neither the name of Google Inc. nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * */ #include "src/core/ext/client_config/client_channel.h" #include #include #include #include #include #include #include #include "src/core/ext/client_config/lb_policy_registry.h" #include "src/core/ext/client_config/method_config.h" #include "src/core/ext/client_config/subchannel.h" #include "src/core/lib/channel/channel_args.h" #include "src/core/lib/channel/connected_channel.h" #include "src/core/lib/channel/deadline_filter.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/support/string.h" #include "src/core/lib/surface/channel.h" #include "src/core/lib/transport/connectivity_state.h" #include "src/core/lib/transport/metadata.h" #include "src/core/lib/transport/metadata_batch.h" #include "src/core/lib/transport/static_metadata.h" /* Client channel implementation */ /************************************************************************* * CHANNEL-WIDE FUNCTIONS */ typedef struct client_channel_channel_data { /** resolver for this channel */ grpc_resolver *resolver; /** have we started resolving this channel */ bool started_resolving; /** client channel factory */ grpc_client_channel_factory *client_channel_factory; /** mutex protecting all variables below in this data structure */ gpr_mu mu; /** currently active load balancer */ grpc_lb_policy *lb_policy; /** method config table */ grpc_method_config_table *method_config_table; /** incoming resolver result - set by resolver.next() */ grpc_resolver_result *resolver_result; /** a list of closures that are all waiting for config to come in */ grpc_closure_list waiting_for_config_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) */ grpc_pollset_set *interested_parties; } channel_data; /** 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_lb_policy *lb_policy; } lb_policy_connectivity_watcher; static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand, grpc_lb_policy *lb_policy, grpc_connectivity_state current_state); static void set_channel_connectivity_state_locked(grpc_exec_ctx *exec_ctx, channel_data *chand, grpc_connectivity_state state, grpc_error *error, const char *reason) { if ((state == GRPC_CHANNEL_TRANSIENT_FAILURE || state == GRPC_CHANNEL_SHUTDOWN) && chand->lb_policy != NULL) { /* cancel picks with wait_for_ready=false */ grpc_lb_policy_cancel_picks( exec_ctx, chand->lb_policy, /* mask= */ GRPC_INITIAL_METADATA_WAIT_FOR_READY, /* check= */ 0, GRPC_ERROR_REF(error)); } grpc_connectivity_state_set(exec_ctx, &chand->state_tracker, state, error, reason); } static void on_lb_policy_state_changed_locked(grpc_exec_ctx *exec_ctx, lb_policy_connectivity_watcher *w, grpc_error *error) { grpc_connectivity_state publish_state = w->state; /* check if the notification is for a stale policy */ if (w->lb_policy != w->chand->lb_policy) return; if (publish_state == GRPC_CHANNEL_SHUTDOWN && w->chand->resolver != NULL) { publish_state = GRPC_CHANNEL_TRANSIENT_FAILURE; grpc_resolver_channel_saw_error(exec_ctx, w->chand->resolver); GRPC_LB_POLICY_UNREF(exec_ctx, w->chand->lb_policy, "channel"); w->chand->lb_policy = NULL; } set_channel_connectivity_state_locked(exec_ctx, w->chand, publish_state, GRPC_ERROR_REF(error), "lb_changed"); if (w->state != GRPC_CHANNEL_SHUTDOWN) { watch_lb_policy(exec_ctx, w->chand, w->lb_policy, w->state); } } static void on_lb_policy_state_changed(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { lb_policy_connectivity_watcher *w = arg; gpr_mu_lock(&w->chand->mu); on_lb_policy_state_changed_locked(exec_ctx, w, error); gpr_mu_unlock(&w->chand->mu); GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack, "watch_lb_policy"); gpr_free(w); } static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand, grpc_lb_policy *lb_policy, grpc_connectivity_state current_state) { lb_policy_connectivity_watcher *w = 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, w); w->state = current_state; w->lb_policy = lb_policy; grpc_lb_policy_notify_on_state_change(exec_ctx, lb_policy, &w->state, &w->on_changed); } static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { channel_data *chand = arg; grpc_lb_policy *lb_policy = NULL; grpc_lb_policy *old_lb_policy; grpc_method_config_table *method_config_table = NULL; grpc_connectivity_state state = GRPC_CHANNEL_TRANSIENT_FAILURE; bool exit_idle = false; grpc_error *state_error = GRPC_ERROR_CREATE("No load balancing policy"); if (chand->resolver_result != NULL) { grpc_lb_policy_args lb_policy_args; lb_policy_args.server_name = grpc_resolver_result_get_server_name(chand->resolver_result); lb_policy_args.addresses = grpc_resolver_result_get_addresses(chand->resolver_result); lb_policy_args.additional_args = grpc_resolver_result_get_lb_policy_args(chand->resolver_result); lb_policy_args.client_channel_factory = chand->client_channel_factory; // Special case: If all of the addresses are balancer addresses, // assume that we should use the grpclb policy, regardless of what the // resolver actually specified. const char *lb_policy_name = grpc_resolver_result_get_lb_policy_name(chand->resolver_result); bool found_backend_address = false; for (size_t i = 0; i < lb_policy_args.addresses->num_addresses; ++i) { if (!lb_policy_args.addresses->addresses[i].is_balancer) { found_backend_address = true; break; } } if (!found_backend_address) { if (lb_policy_name != NULL && strcmp(lb_policy_name, "grpclb") != 0) { gpr_log(GPR_INFO, "resolver requested LB policy %s but provided only balancer " "addresses, no backend addresses -- forcing use of grpclb LB " "policy", (lb_policy_name == NULL ? "(none)" : lb_policy_name)); } lb_policy_name = "grpclb"; } // Use pick_first if nothing was specified and we didn't select grpclb // above. if (lb_policy_name == NULL) lb_policy_name = "pick_first"; lb_policy = grpc_lb_policy_create(exec_ctx, lb_policy_name, &lb_policy_args); if (lb_policy != NULL) { GRPC_LB_POLICY_REF(lb_policy, "config_change"); GRPC_ERROR_UNREF(state_error); state = grpc_lb_policy_check_connectivity(exec_ctx, lb_policy, &state_error); } const grpc_arg *channel_arg = grpc_channel_args_find( lb_policy_args.additional_args, GRPC_ARG_SERVICE_CONFIG); if (channel_arg != NULL) { GPR_ASSERT(channel_arg->type == GRPC_ARG_POINTER); method_config_table = grpc_method_config_table_ref( (grpc_method_config_table *)channel_arg->value.pointer.p); } grpc_resolver_result_unref(exec_ctx, chand->resolver_result); chand->resolver_result = NULL; } if (lb_policy != NULL) { grpc_pollset_set_add_pollset_set(exec_ctx, lb_policy->interested_parties, chand->interested_parties); } gpr_mu_lock(&chand->mu); old_lb_policy = chand->lb_policy; chand->lb_policy = lb_policy; if (chand->method_config_table != NULL) { grpc_method_config_table_unref(chand->method_config_table); } chand->method_config_table = method_config_table; if (lb_policy != NULL) { grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures, NULL); } else if (chand->resolver == NULL /* disconnected */) { grpc_closure_list_fail_all( &chand->waiting_for_config_closures, GRPC_ERROR_CREATE_REFERENCING("Channel disconnected", &error, 1)); grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures, NULL); } if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) { GRPC_LB_POLICY_REF(lb_policy, "exit_idle"); exit_idle = true; chand->exit_idle_when_lb_policy_arrives = false; } if (error == GRPC_ERROR_NONE && chand->resolver) { set_channel_connectivity_state_locked( exec_ctx, chand, state, GRPC_ERROR_REF(state_error), "new_lb+resolver"); if (lb_policy != NULL) { watch_lb_policy(exec_ctx, chand, lb_policy, state); } GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver"); grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result, &chand->on_resolver_result_changed); gpr_mu_unlock(&chand->mu); } else { if (chand->resolver != NULL) { grpc_resolver_shutdown(exec_ctx, chand->resolver); GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel"); chand->resolver = NULL; } grpc_error *refs[] = {error, state_error}; set_channel_connectivity_state_locked( exec_ctx, chand, GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_CREATE_REFERENCING("Got config after disconnection", refs, GPR_ARRAY_SIZE(refs)), "resolver_gone"); gpr_mu_unlock(&chand->mu); } if (exit_idle) { grpc_lb_policy_exit_idle(exec_ctx, lb_policy); GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "exit_idle"); } if (old_lb_policy != NULL) { grpc_pollset_set_del_pollset_set( exec_ctx, old_lb_policy->interested_parties, chand->interested_parties); GRPC_LB_POLICY_UNREF(exec_ctx, old_lb_policy, "channel"); } if (lb_policy != NULL) { GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "config_change"); } GRPC_CHANNEL_STACK_UNREF(exec_ctx, chand->owning_stack, "resolver"); GRPC_ERROR_UNREF(state_error); } static void cc_start_transport_op(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_transport_op *op) { channel_data *chand = elem->channel_data; grpc_exec_ctx_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE, NULL); GPR_ASSERT(op->set_accept_stream == false); if (op->bind_pollset != NULL) { grpc_pollset_set_add_pollset(exec_ctx, chand->interested_parties, op->bind_pollset); } gpr_mu_lock(&chand->mu); if (op->on_connectivity_state_change != NULL) { grpc_connectivity_state_notify_on_state_change( exec_ctx, &chand->state_tracker, op->connectivity_state, op->on_connectivity_state_change); op->on_connectivity_state_change = NULL; op->connectivity_state = NULL; } if (op->send_ping != NULL) { if (chand->lb_policy == NULL) { grpc_exec_ctx_sched(exec_ctx, op->send_ping, GRPC_ERROR_CREATE("Ping with no load balancing"), NULL); } else { grpc_lb_policy_ping_one(exec_ctx, chand->lb_policy, op->send_ping); op->bind_pollset = NULL; } op->send_ping = NULL; } if (op->disconnect_with_error != GRPC_ERROR_NONE) { if (chand->resolver != NULL) { set_channel_connectivity_state_locked( exec_ctx, chand, GRPC_CHANNEL_SHUTDOWN, GRPC_ERROR_REF(op->disconnect_with_error), "disconnect"); grpc_resolver_shutdown(exec_ctx, chand->resolver); GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel"); chand->resolver = NULL; if (!chand->started_resolving) { grpc_closure_list_fail_all(&chand->waiting_for_config_closures, GRPC_ERROR_REF(op->disconnect_with_error)); grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures, NULL); } if (chand->lb_policy != NULL) { grpc_pollset_set_del_pollset_set(exec_ctx, chand->lb_policy->interested_parties, chand->interested_parties); GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel"); chand->lb_policy = NULL; } } GRPC_ERROR_UNREF(op->disconnect_with_error); } gpr_mu_unlock(&chand->mu); } /* Constructor for channel_data */ static void cc_init_channel_elem(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_channel_element_args *args) { channel_data *chand = elem->channel_data; memset(chand, 0, sizeof(*chand)); GPR_ASSERT(args->is_last); GPR_ASSERT(elem->filter == &grpc_client_channel_filter); gpr_mu_init(&chand->mu); grpc_closure_init(&chand->on_resolver_result_changed, on_resolver_result_changed, chand); chand->owning_stack = args->channel_stack; grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE, "client_channel"); chand->interested_parties = grpc_pollset_set_create(); } /* Destructor for channel_data */ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem) { channel_data *chand = elem->channel_data; if (chand->resolver != NULL) { grpc_resolver_shutdown(exec_ctx, chand->resolver); GRPC_RESOLVER_UNREF(exec_ctx, chand->resolver, "channel"); } if (chand->client_channel_factory != NULL) { grpc_client_channel_factory_unref(exec_ctx, chand->client_channel_factory); } if (chand->lb_policy != NULL) { grpc_pollset_set_del_pollset_set(exec_ctx, chand->lb_policy->interested_parties, chand->interested_parties); GRPC_LB_POLICY_UNREF(exec_ctx, chand->lb_policy, "channel"); } if (chand->method_config_table != NULL) { grpc_method_config_table_unref(chand->method_config_table); } grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker); grpc_pollset_set_destroy(chand->interested_parties); gpr_mu_destroy(&chand->mu); } /************************************************************************* * PER-CALL FUNCTIONS */ #define GET_CALL(call_data) \ ((grpc_subchannel_call *)(gpr_atm_acq_load(&(call_data)->subchannel_call))) #define CANCELLED_CALL ((grpc_subchannel_call *)1) typedef enum { GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING, GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL } subchannel_creation_phase; /** Call data. Holds a pointer to grpc_subchannel_call and the associated machinery to create such a pointer. Handles queueing of stream ops until a call object is ready, waiting for initial metadata before trying to create a call object, and handling cancellation gracefully. */ typedef struct client_channel_call_data { // State for handling deadlines. // The code in deadline_filter.c requires this to be the first field. // TODO(roth): This is slightly sub-optimal in that grpc_deadline_state // and this struct both independently store a pointer to the call // stack and each has its own mutex. If/when we have time, find a way // to avoid this without breaking the grpc_deadline_state abstraction. grpc_deadline_state deadline_state; grpc_mdstr *path; // Request path. gpr_timespec call_start_time; gpr_timespec deadline; enum { WAIT_FOR_READY_UNSET, WAIT_FOR_READY_FALSE, WAIT_FOR_READY_TRUE } wait_for_ready_from_service_config; grpc_closure read_service_config; grpc_error *cancel_error; /** either 0 for no call, 1 for cancelled, or a pointer to a grpc_subchannel_call */ gpr_atm subchannel_call; gpr_mu mu; subchannel_creation_phase creation_phase; grpc_connected_subchannel *connected_subchannel; grpc_polling_entity *pollent; grpc_transport_stream_op **waiting_ops; size_t waiting_ops_count; size_t waiting_ops_capacity; grpc_closure next_step; grpc_call_stack *owning_call; grpc_linked_mdelem lb_token_mdelem; } call_data; static void add_waiting_locked(call_data *calld, grpc_transport_stream_op *op) { GPR_TIMER_BEGIN("add_waiting_locked", 0); if (calld->waiting_ops_count == calld->waiting_ops_capacity) { calld->waiting_ops_capacity = GPR_MAX(3, 2 * calld->waiting_ops_capacity); calld->waiting_ops = gpr_realloc(calld->waiting_ops, calld->waiting_ops_capacity * sizeof(*calld->waiting_ops)); } calld->waiting_ops[calld->waiting_ops_count++] = op; GPR_TIMER_END("add_waiting_locked", 0); } static void fail_locked(grpc_exec_ctx *exec_ctx, call_data *calld, grpc_error *error) { size_t i; for (i = 0; i < calld->waiting_ops_count; i++) { grpc_transport_stream_op_finish_with_failure( exec_ctx, calld->waiting_ops[i], GRPC_ERROR_REF(error)); } calld->waiting_ops_count = 0; GRPC_ERROR_UNREF(error); } typedef struct { grpc_transport_stream_op **ops; size_t nops; grpc_subchannel_call *call; } retry_ops_args; static void retry_ops(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) { retry_ops_args *a = args; size_t i; for (i = 0; i < a->nops; i++) { grpc_subchannel_call_process_op(exec_ctx, a->call, a->ops[i]); } GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, a->call, "retry_ops"); gpr_free(a->ops); gpr_free(a); } static void retry_waiting_locked(grpc_exec_ctx *exec_ctx, call_data *calld) { if (calld->waiting_ops_count == 0) { return; } retry_ops_args *a = gpr_malloc(sizeof(*a)); a->ops = calld->waiting_ops; a->nops = calld->waiting_ops_count; a->call = GET_CALL(calld); if (a->call == CANCELLED_CALL) { gpr_free(a); fail_locked(exec_ctx, calld, GRPC_ERROR_CANCELLED); return; } calld->waiting_ops = NULL; calld->waiting_ops_count = 0; calld->waiting_ops_capacity = 0; GRPC_SUBCHANNEL_CALL_REF(a->call, "retry_ops"); grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(retry_ops, a), GRPC_ERROR_NONE, NULL); } static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { grpc_call_element *elem = arg; call_data *calld = elem->call_data; channel_data *chand = elem->channel_data; gpr_mu_lock(&calld->mu); GPR_ASSERT(calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL); grpc_polling_entity_del_from_pollset_set(exec_ctx, calld->pollent, chand->interested_parties); calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; if (calld->connected_subchannel == NULL) { gpr_atm_no_barrier_store(&calld->subchannel_call, 1); fail_locked(exec_ctx, calld, GRPC_ERROR_CREATE_REFERENCING( "Failed to create subchannel", &error, 1)); } else if (GET_CALL(calld) == CANCELLED_CALL) { /* already cancelled before subchannel became ready */ fail_locked(exec_ctx, calld, GRPC_ERROR_CREATE_REFERENCING( "Cancelled before creating subchannel", &error, 1)); } else { /* Create call on subchannel. */ grpc_subchannel_call *subchannel_call = NULL; grpc_error *new_error = grpc_connected_subchannel_create_call( exec_ctx, calld->connected_subchannel, calld->pollent, calld->path, calld->deadline, &subchannel_call); if (new_error != GRPC_ERROR_NONE) { new_error = grpc_error_add_child(new_error, error); subchannel_call = CANCELLED_CALL; fail_locked(exec_ctx, calld, new_error); } gpr_atm_rel_store(&calld->subchannel_call, (gpr_atm)(uintptr_t)subchannel_call); retry_waiting_locked(exec_ctx, calld); } gpr_mu_unlock(&calld->mu); GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); } static char *cc_get_peer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) { call_data *calld = elem->call_data; grpc_subchannel_call *subchannel_call = GET_CALL(calld); if (subchannel_call == NULL || subchannel_call == CANCELLED_CALL) { return NULL; } else { return grpc_subchannel_call_get_peer(exec_ctx, subchannel_call); } } typedef struct { grpc_metadata_batch *initial_metadata; uint32_t initial_metadata_flags; grpc_connected_subchannel **connected_subchannel; grpc_closure *on_ready; grpc_call_element *elem; grpc_closure closure; } continue_picking_args; /** Return true if subchannel is available immediately (in which case on_ready should not be called), or false otherwise (in which case on_ready should be called when the subchannel is available). */ static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_metadata_batch *initial_metadata, uint32_t initial_metadata_flags, grpc_connected_subchannel **connected_subchannel, grpc_closure *on_ready, grpc_error *error); static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { continue_picking_args *cpa = arg; if (cpa->connected_subchannel == NULL) { /* cancelled, do nothing */ } else if (error != GRPC_ERROR_NONE) { grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_REF(error), NULL); } else { call_data *calld = cpa->elem->call_data; gpr_mu_lock(&calld->mu); if (pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata, cpa->initial_metadata_flags, cpa->connected_subchannel, cpa->on_ready, GRPC_ERROR_NONE)) { grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_NONE, NULL); } gpr_mu_unlock(&calld->mu); } gpr_free(cpa); } static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_metadata_batch *initial_metadata, uint32_t initial_metadata_flags, grpc_connected_subchannel **connected_subchannel, grpc_closure *on_ready, grpc_error *error) { GPR_TIMER_BEGIN("pick_subchannel", 0); channel_data *chand = elem->channel_data; call_data *calld = elem->call_data; continue_picking_args *cpa; grpc_closure *closure; GPR_ASSERT(connected_subchannel); gpr_mu_lock(&chand->mu); if (initial_metadata == NULL) { if (chand->lb_policy != NULL) { grpc_lb_policy_cancel_pick(exec_ctx, chand->lb_policy, connected_subchannel, GRPC_ERROR_REF(error)); } for (closure = chand->waiting_for_config_closures.head; closure != NULL; closure = closure->next_data.next) { cpa = closure->cb_arg; if (cpa->connected_subchannel == connected_subchannel) { cpa->connected_subchannel = NULL; grpc_exec_ctx_sched( exec_ctx, cpa->on_ready, GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1), NULL); } } gpr_mu_unlock(&chand->mu); GPR_TIMER_END("pick_subchannel", 0); GRPC_ERROR_UNREF(error); return true; } GPR_ASSERT(error == GRPC_ERROR_NONE); if (chand->lb_policy != NULL) { grpc_lb_policy *lb_policy = chand->lb_policy; GRPC_LB_POLICY_REF(lb_policy, "pick_subchannel"); gpr_mu_unlock(&chand->mu); // If the application explicitly set wait_for_ready, use that. // Otherwise, if the service config specified a value for this // method, use that. const bool wait_for_ready_set_from_api = initial_metadata_flags & GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET; const bool wait_for_ready_set_from_service_config = calld->wait_for_ready_from_service_config != WAIT_FOR_READY_UNSET; if (!wait_for_ready_set_from_api && wait_for_ready_set_from_service_config) { if (calld->wait_for_ready_from_service_config == WAIT_FOR_READY_TRUE) { initial_metadata_flags |= GRPC_INITIAL_METADATA_WAIT_FOR_READY; } else { initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY; } } // TODO(dgq): make this deadline configurable somehow. const grpc_lb_policy_pick_args inputs = { initial_metadata, initial_metadata_flags, &calld->lb_token_mdelem, gpr_inf_future(GPR_CLOCK_MONOTONIC)}; const bool result = grpc_lb_policy_pick( exec_ctx, lb_policy, &inputs, connected_subchannel, NULL, on_ready); GRPC_LB_POLICY_UNREF(exec_ctx, lb_policy, "pick_subchannel"); GPR_TIMER_END("pick_subchannel", 0); return result; } if (chand->resolver != NULL && !chand->started_resolving) { chand->started_resolving = true; GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver"); grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result, &chand->on_resolver_result_changed); } if (chand->resolver != NULL) { cpa = gpr_malloc(sizeof(*cpa)); cpa->initial_metadata = initial_metadata; cpa->initial_metadata_flags = initial_metadata_flags; cpa->connected_subchannel = connected_subchannel; cpa->on_ready = on_ready; cpa->elem = elem; grpc_closure_init(&cpa->closure, continue_picking, cpa); grpc_closure_list_append(&chand->waiting_for_config_closures, &cpa->closure, GRPC_ERROR_NONE); } else { grpc_exec_ctx_sched(exec_ctx, on_ready, GRPC_ERROR_CREATE("Disconnected"), NULL); } gpr_mu_unlock(&chand->mu); GPR_TIMER_END("pick_subchannel", 0); return false; } // The logic here is fairly complicated, due to (a) the fact that we // need to handle the case where we receive the send op before the // initial metadata op, and (b) the need for efficiency, especially in // the streaming case. // TODO(ctiller): Explain this more thoroughly. static void cc_start_transport_stream_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_transport_stream_op *op) { call_data *calld = elem->call_data; channel_data *chand = elem->channel_data; GRPC_CALL_LOG_OP(GPR_INFO, elem, op); grpc_deadline_state_client_start_transport_stream_op(exec_ctx, elem, op); /* try to (atomically) get the call */ grpc_subchannel_call *call = GET_CALL(calld); GPR_TIMER_BEGIN("cc_start_transport_stream_op", 0); if (call == CANCELLED_CALL) { grpc_transport_stream_op_finish_with_failure( exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error)); GPR_TIMER_END("cc_start_transport_stream_op", 0); return; } if (call != NULL) { grpc_subchannel_call_process_op(exec_ctx, call, op); GPR_TIMER_END("cc_start_transport_stream_op", 0); return; } /* we failed; lock and figure out what to do */ gpr_mu_lock(&calld->mu); retry: /* need to recheck that another thread hasn't set the call */ call = GET_CALL(calld); if (call == CANCELLED_CALL) { gpr_mu_unlock(&calld->mu); grpc_transport_stream_op_finish_with_failure( exec_ctx, op, GRPC_ERROR_REF(calld->cancel_error)); GPR_TIMER_END("cc_start_transport_stream_op", 0); return; } if (call != NULL) { gpr_mu_unlock(&calld->mu); grpc_subchannel_call_process_op(exec_ctx, call, op); GPR_TIMER_END("cc_start_transport_stream_op", 0); return; } /* if this is a cancellation, then we can raise our cancelled flag */ if (op->cancel_error != GRPC_ERROR_NONE) { if (!gpr_atm_rel_cas(&calld->subchannel_call, 0, (gpr_atm)(uintptr_t)CANCELLED_CALL)) { goto retry; } else { // Stash a copy of cancel_error in our call data, so that we can use // it for subsequent operations. This ensures that if the call is // cancelled before any ops are passed down (e.g., if the deadline // is in the past when the call starts), we can return the right // error to the caller when the first op does get passed down. calld->cancel_error = GRPC_ERROR_REF(op->cancel_error); switch (calld->creation_phase) { case GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING: fail_locked(exec_ctx, calld, GRPC_ERROR_REF(op->cancel_error)); break; case GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL: pick_subchannel(exec_ctx, elem, NULL, 0, &calld->connected_subchannel, NULL, GRPC_ERROR_REF(op->cancel_error)); break; } gpr_mu_unlock(&calld->mu); grpc_transport_stream_op_finish_with_failure( exec_ctx, op, GRPC_ERROR_REF(op->cancel_error)); GPR_TIMER_END("cc_start_transport_stream_op", 0); return; } } /* if we don't have a subchannel, try to get one */ if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && calld->connected_subchannel == NULL && op->send_initial_metadata != NULL) { calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL; grpc_closure_init(&calld->next_step, subchannel_ready, elem); GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel"); /* If a subchannel is not available immediately, the polling entity from call_data should be provided to channel_data's interested_parties, so that IO of the lb_policy and resolver could be done under it. */ if (pick_subchannel(exec_ctx, elem, op->send_initial_metadata, op->send_initial_metadata_flags, &calld->connected_subchannel, &calld->next_step, GRPC_ERROR_NONE)) { calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "pick_subchannel"); } else { grpc_polling_entity_add_to_pollset_set(exec_ctx, calld->pollent, chand->interested_parties); } } /* if we've got a subchannel, then let's ask it to create a call */ if (calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING && calld->connected_subchannel != NULL) { grpc_subchannel_call *subchannel_call = NULL; grpc_error *error = grpc_connected_subchannel_create_call( exec_ctx, calld->connected_subchannel, calld->pollent, calld->path, calld->deadline, &subchannel_call); if (error != GRPC_ERROR_NONE) { subchannel_call = CANCELLED_CALL; fail_locked(exec_ctx, calld, GRPC_ERROR_REF(error)); grpc_transport_stream_op_finish_with_failure(exec_ctx, op, error); } gpr_atm_rel_store(&calld->subchannel_call, (gpr_atm)(uintptr_t)subchannel_call); retry_waiting_locked(exec_ctx, calld); goto retry; } /* nothing to be done but wait */ add_waiting_locked(calld, op); gpr_mu_unlock(&calld->mu); GPR_TIMER_END("cc_start_transport_stream_op", 0); } // Gets data from the service config. Invoked when the resolver returns // its initial result. static void read_service_config(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { grpc_call_element *elem = arg; channel_data *chand = elem->channel_data; call_data *calld = elem->call_data; // If this is an error, there's no point in looking at the service config. if (error == GRPC_ERROR_NONE) { // Get the method config table from channel data. gpr_mu_lock(&chand->mu); grpc_method_config_table *method_config_table = NULL; if (chand->method_config_table != NULL) { method_config_table = grpc_method_config_table_ref(chand->method_config_table); } gpr_mu_unlock(&chand->mu); // If the method config table was present, use it. if (method_config_table != NULL) { const grpc_method_config *method_config = grpc_method_config_table_get_method_config(method_config_table, calld->path); if (method_config != NULL) { const gpr_timespec *per_method_timeout = grpc_method_config_get_timeout(method_config); const bool *wait_for_ready = grpc_method_config_get_wait_for_ready(method_config); if (per_method_timeout != NULL || wait_for_ready != NULL) { gpr_mu_lock(&calld->mu); if (per_method_timeout != NULL) { gpr_timespec per_method_deadline = gpr_time_add(calld->call_start_time, *per_method_timeout); if (gpr_time_cmp(per_method_deadline, calld->deadline) < 0) { calld->deadline = per_method_deadline; // Reset deadline timer. grpc_deadline_state_reset(exec_ctx, elem, calld->deadline); } } if (wait_for_ready != NULL) { calld->wait_for_ready_from_service_config = *wait_for_ready ? WAIT_FOR_READY_TRUE : WAIT_FOR_READY_FALSE; } gpr_mu_unlock(&calld->mu); } } grpc_method_config_table_unref(method_config_table); } } GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "read_service_config"); } /* Constructor for call_data */ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_call_element_args *args) { channel_data *chand = elem->channel_data; call_data *calld = elem->call_data; // Initialize data members. grpc_deadline_state_init(exec_ctx, elem, args->call_stack); calld->path = GRPC_MDSTR_REF(args->path); calld->call_start_time = args->start_time; calld->deadline = gpr_convert_clock_type(args->deadline, GPR_CLOCK_MONOTONIC); calld->wait_for_ready_from_service_config = WAIT_FOR_READY_UNSET; calld->cancel_error = GRPC_ERROR_NONE; gpr_atm_rel_store(&calld->subchannel_call, 0); gpr_mu_init(&calld->mu); calld->connected_subchannel = NULL; calld->waiting_ops = NULL; calld->waiting_ops_count = 0; calld->waiting_ops_capacity = 0; calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING; calld->owning_call = args->call_stack; calld->pollent = NULL; // If the resolver has already returned results, then we can access // the service config parameters immediately. Otherwise, we need to // defer that work until the resolver returns an initial result. // TODO(roth): This code is almost but not quite identical to the code // in read_service_config() above. It would be nice to find a way to // combine them, to avoid having to maintain it twice. gpr_mu_lock(&chand->mu); if (chand->lb_policy != NULL) { // We already have a resolver result, so check for service config. if (chand->method_config_table != NULL) { grpc_method_config_table *method_config_table = grpc_method_config_table_ref(chand->method_config_table); gpr_mu_unlock(&chand->mu); grpc_method_config *method_config = grpc_method_config_table_get_method_config(method_config_table, args->path); if (method_config != NULL) { const gpr_timespec *per_method_timeout = grpc_method_config_get_timeout(method_config); if (per_method_timeout != NULL) { gpr_timespec per_method_deadline = gpr_time_add(calld->call_start_time, *per_method_timeout); calld->deadline = gpr_time_min(calld->deadline, per_method_deadline); } const bool *wait_for_ready = grpc_method_config_get_wait_for_ready(method_config); if (wait_for_ready != NULL) { calld->wait_for_ready_from_service_config = *wait_for_ready ? WAIT_FOR_READY_TRUE : WAIT_FOR_READY_FALSE; } } grpc_method_config_table_unref(method_config_table); } else { gpr_mu_unlock(&chand->mu); } } else { // We don't yet have a resolver result, so register a callback to // get the service config data once the resolver returns. // Take a reference to the call stack to be owned by the callback. GRPC_CALL_STACK_REF(calld->owning_call, "read_service_config"); grpc_closure_init(&calld->read_service_config, read_service_config, elem); grpc_closure_list_append(&chand->waiting_for_config_closures, &calld->read_service_config, GRPC_ERROR_NONE); gpr_mu_unlock(&chand->mu); } // Start the deadline timer with the current deadline value. If we // do not yet have service config data, then the timer may be reset // later. grpc_deadline_state_start(exec_ctx, elem, calld->deadline); return GRPC_ERROR_NONE; } /* Destructor for call_data */ static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, const grpc_call_final_info *final_info, void *and_free_memory) { call_data *calld = elem->call_data; grpc_deadline_state_destroy(exec_ctx, elem); GRPC_MDSTR_UNREF(calld->path); GRPC_ERROR_UNREF(calld->cancel_error); grpc_subchannel_call *call = GET_CALL(calld); if (call != NULL && call != CANCELLED_CALL) { GRPC_SUBCHANNEL_CALL_UNREF(exec_ctx, call, "client_channel_destroy_call"); } GPR_ASSERT(calld->creation_phase == GRPC_SUBCHANNEL_CALL_HOLDER_NOT_CREATING); gpr_mu_destroy(&calld->mu); GPR_ASSERT(calld->waiting_ops_count == 0); gpr_free(calld->waiting_ops); gpr_free(and_free_memory); } static void cc_set_pollset_or_pollset_set(grpc_exec_ctx *exec_ctx, grpc_call_element *elem, grpc_polling_entity *pollent) { call_data *calld = elem->call_data; calld->pollent = pollent; } /************************************************************************* * EXPORTED SYMBOLS */ const grpc_channel_filter grpc_client_channel_filter = { cc_start_transport_stream_op, cc_start_transport_op, sizeof(call_data), cc_init_call_elem, cc_set_pollset_or_pollset_set, cc_destroy_call_elem, sizeof(channel_data), cc_init_channel_elem, cc_destroy_channel_elem, cc_get_peer, "client-channel", }; void grpc_client_channel_finish_initialization( grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack, grpc_resolver *resolver, grpc_client_channel_factory *client_channel_factory) { /* post construction initialization: set the transport setup pointer */ GPR_ASSERT(client_channel_factory != NULL); grpc_channel_element *elem = grpc_channel_stack_last_element(channel_stack); channel_data *chand = elem->channel_data; gpr_mu_lock(&chand->mu); GPR_ASSERT(!chand->resolver); chand->resolver = resolver; GRPC_RESOLVER_REF(resolver, "channel"); if (!grpc_closure_list_empty(chand->waiting_for_config_closures) || chand->exit_idle_when_lb_policy_arrives) { chand->started_resolving = true; GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver"); grpc_resolver_next(exec_ctx, resolver, &chand->resolver_result, &chand->on_resolver_result_changed); } chand->client_channel_factory = client_channel_factory; grpc_client_channel_factory_ref(client_channel_factory); gpr_mu_unlock(&chand->mu); } grpc_connectivity_state grpc_client_channel_check_connectivity_state( grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect) { channel_data *chand = elem->channel_data; grpc_connectivity_state out; gpr_mu_lock(&chand->mu); out = grpc_connectivity_state_check(&chand->state_tracker, NULL); if (out == GRPC_CHANNEL_IDLE && try_to_connect) { if (chand->lb_policy != NULL) { grpc_lb_policy_exit_idle(exec_ctx, chand->lb_policy); } else { chand->exit_idle_when_lb_policy_arrives = true; if (!chand->started_resolving && chand->resolver != NULL) { GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver"); chand->started_resolving = true; grpc_resolver_next(exec_ctx, chand->resolver, &chand->resolver_result, &chand->on_resolver_result_changed); } } } gpr_mu_unlock(&chand->mu); return out; } typedef struct { channel_data *chand; grpc_pollset *pollset; grpc_closure *on_complete; grpc_closure my_closure; } external_connectivity_watcher; static void on_external_watch_complete(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) { external_connectivity_watcher *w = arg; grpc_closure *follow_up = w->on_complete; grpc_pollset_set_del_pollset(exec_ctx, w->chand->interested_parties, w->pollset); GRPC_CHANNEL_STACK_UNREF(exec_ctx, w->chand->owning_stack, "external_connectivity_watcher"); gpr_free(w); follow_up->cb(exec_ctx, follow_up->cb_arg, error); } void grpc_client_channel_watch_connectivity_state( grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, grpc_pollset *pollset, grpc_connectivity_state *state, grpc_closure *on_complete) { channel_data *chand = elem->channel_data; external_connectivity_watcher *w = gpr_malloc(sizeof(*w)); w->chand = chand; w->pollset = pollset; w->on_complete = on_complete; grpc_pollset_set_add_pollset(exec_ctx, chand->interested_parties, pollset); grpc_closure_init(&w->my_closure, on_external_watch_complete, w); GRPC_CHANNEL_STACK_REF(w->chand->owning_stack, "external_connectivity_watcher"); gpr_mu_lock(&chand->mu); grpc_connectivity_state_notify_on_state_change( exec_ctx, &chand->state_tracker, state, &w->my_closure); gpr_mu_unlock(&chand->mu); }