diff options
Diffstat (limited to 'src/core/ext/filters/client_channel/resolver')
-rw-r--r-- | src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc | 84 | ||||
-rw-r--r-- | src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc | 89 |
2 files changed, 126 insertions, 47 deletions
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc index 0315a29d15..e5b2815af8 100644 --- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc +++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc @@ -66,8 +66,8 @@ typedef struct { grpc_pollset_set* interested_parties; /** Closures used by the combiner */ - grpc_closure dns_ares_on_retry_timer_locked; - grpc_closure dns_ares_on_resolved_locked; + grpc_closure dns_ares_on_next_resolution_timer_closure; + grpc_closure dns_ares_on_resolved_closure; /** Combiner guarding the rest of the state */ grpc_combiner* combiner; @@ -85,12 +85,15 @@ typedef struct { grpc_channel_args** target_result; /** current (fully resolved) result */ grpc_channel_args* resolved_result; - /** retry timer */ - bool have_retry_timer; - grpc_timer retry_timer; + /** next resolution timer */ + bool have_next_resolution_timer; + grpc_timer next_resolution_timer; /** retry backoff state */ grpc_core::ManualConstructor<grpc_core::BackOff> backoff; - + /** min resolution period. Max one resolution will happen per period */ + grpc_millis min_time_between_resolutions; + /** when was the last resolution? -1 if no resolution has happened yet */ + grpc_millis last_resolution_timestamp; /** currently resolving addresses */ grpc_lb_addresses* lb_addresses; /** currently resolving service config */ @@ -100,6 +103,7 @@ typedef struct { static void dns_ares_destroy(grpc_resolver* r); static void dns_ares_start_resolving_locked(ares_dns_resolver* r); +static void dns_ares_maybe_start_resolving_locked(ares_dns_resolver* r); static void dns_ares_maybe_finish_next_locked(ares_dns_resolver* r); static void dns_ares_shutdown_locked(grpc_resolver* r); @@ -114,8 +118,8 @@ static const grpc_resolver_vtable dns_ares_resolver_vtable = { static void dns_ares_shutdown_locked(grpc_resolver* resolver) { ares_dns_resolver* r = (ares_dns_resolver*)resolver; - if (r->have_retry_timer) { - grpc_timer_cancel(&r->retry_timer); + if (r->have_next_resolution_timer) { + grpc_timer_cancel(&r->next_resolution_timer); } if (r->pending_request != nullptr) { grpc_cancel_ares_request(r->pending_request); @@ -131,19 +135,20 @@ static void dns_ares_shutdown_locked(grpc_resolver* resolver) { static void dns_ares_channel_saw_error_locked(grpc_resolver* resolver) { ares_dns_resolver* r = (ares_dns_resolver*)resolver; if (!r->resolving) { - dns_ares_start_resolving_locked(r); + dns_ares_maybe_start_resolving_locked(r); } } -static void dns_ares_on_retry_timer_locked(void* arg, grpc_error* error) { +static void dns_ares_on_next_resolution_timer_locked(void* arg, + grpc_error* error) { ares_dns_resolver* r = (ares_dns_resolver*)arg; - r->have_retry_timer = false; + r->have_next_resolution_timer = false; if (error == GRPC_ERROR_NONE) { if (!r->resolving) { dns_ares_start_resolving_locked(r); } } - GRPC_RESOLVER_UNREF(&r->base, "retry-timer"); + GRPC_RESOLVER_UNREF(&r->base, "next_resolution_timer"); } static bool value_in_json_array(grpc_json* array, const char* value) { @@ -270,21 +275,22 @@ static void dns_ares_on_resolved_locked(void* arg, grpc_error* error) { grpc_millis timeout = next_try - grpc_core::ExecCtx::Get()->Now(); gpr_log(GPR_INFO, "dns resolution failed (will retry): %s", grpc_error_string(error)); - GPR_ASSERT(!r->have_retry_timer); - r->have_retry_timer = true; - GRPC_RESOLVER_REF(&r->base, "retry-timer"); + GPR_ASSERT(!r->have_next_resolution_timer); + r->have_next_resolution_timer = true; + GRPC_RESOLVER_REF(&r->base, "next_resolution_timer"); if (timeout > 0) { gpr_log(GPR_DEBUG, "retrying in %" PRIdPTR " milliseconds", timeout); } else { gpr_log(GPR_DEBUG, "retrying immediately"); } - grpc_timer_init(&r->retry_timer, next_try, - &r->dns_ares_on_retry_timer_locked); + grpc_timer_init(&r->next_resolution_timer, next_try, + &r->dns_ares_on_next_resolution_timer_closure); } if (r->resolved_result != nullptr) { grpc_channel_args_destroy(r->resolved_result); } r->resolved_result = result; + r->last_resolution_timestamp = grpc_core::ExecCtx::Get()->Now(); r->resolved_version++; dns_ares_maybe_finish_next_locked(r); GRPC_RESOLVER_UNREF(&r->base, "dns-resolving"); @@ -299,7 +305,7 @@ static void dns_ares_next_locked(grpc_resolver* resolver, r->next_completion = on_complete; r->target_result = target_result; if (r->resolved_version == 0 && !r->resolving) { - dns_ares_start_resolving_locked(r); + dns_ares_maybe_start_resolving_locked(r); } else { dns_ares_maybe_finish_next_locked(r); } @@ -313,7 +319,7 @@ static void dns_ares_start_resolving_locked(ares_dns_resolver* r) { r->service_config_json = nullptr; r->pending_request = grpc_dns_lookup_ares( r->dns_server, r->name_to_resolve, r->default_port, r->interested_parties, - &r->dns_ares_on_resolved_locked, &r->lb_addresses, + &r->dns_ares_on_resolved_closure, &r->lb_addresses, true /* check_grpclb */, r->request_service_config ? &r->service_config_json : nullptr); } @@ -331,6 +337,35 @@ static void dns_ares_maybe_finish_next_locked(ares_dns_resolver* r) { } } +static void dns_ares_maybe_start_resolving_locked(ares_dns_resolver* r) { + if (r->last_resolution_timestamp >= 0) { + const grpc_millis earliest_next_resolution = + r->last_resolution_timestamp + r->min_time_between_resolutions; + const grpc_millis ms_until_next_resolution = + earliest_next_resolution - grpc_core::ExecCtx::Get()->Now(); + if (ms_until_next_resolution > 0) { + const grpc_millis last_resolution_ago = + grpc_core::ExecCtx::Get()->Now() - r->last_resolution_timestamp; + gpr_log(GPR_DEBUG, + "In cooldown from last resolution (from %" PRIdPTR + " ms ago). Will resolve again in %" PRIdPTR " ms", + last_resolution_ago, ms_until_next_resolution); + if (!r->have_next_resolution_timer) { + r->have_next_resolution_timer = true; + GRPC_RESOLVER_REF(&r->base, "next_resolution_timer_cooldown"); + grpc_timer_init(&r->next_resolution_timer, ms_until_next_resolution, + &r->dns_ares_on_next_resolution_timer_closure); + } + // TODO(dgq): remove the following two lines once Pick First stops + // discarding subchannels after selecting. + ++r->resolved_version; + dns_ares_maybe_finish_next_locked(r); + return; + } + } + dns_ares_start_resolving_locked(r); +} + static void dns_ares_destroy(grpc_resolver* gr) { gpr_log(GPR_DEBUG, "dns_ares_destroy"); ares_dns_resolver* r = (ares_dns_resolver*)gr; @@ -375,12 +410,17 @@ static grpc_resolver* dns_ares_create(grpc_resolver_args* args, .set_jitter(GRPC_DNS_RECONNECT_JITTER) .set_max_backoff(GRPC_DNS_RECONNECT_MAX_BACKOFF_SECONDS * 1000); r->backoff.Init(grpc_core::BackOff(backoff_options)); - GRPC_CLOSURE_INIT(&r->dns_ares_on_retry_timer_locked, - dns_ares_on_retry_timer_locked, r, + GRPC_CLOSURE_INIT(&r->dns_ares_on_next_resolution_timer_closure, + dns_ares_on_next_resolution_timer_locked, r, grpc_combiner_scheduler(r->base.combiner)); - GRPC_CLOSURE_INIT(&r->dns_ares_on_resolved_locked, + GRPC_CLOSURE_INIT(&r->dns_ares_on_resolved_closure, dns_ares_on_resolved_locked, r, grpc_combiner_scheduler(r->base.combiner)); + const grpc_arg* period_arg = grpc_channel_args_find( + args->args, GRPC_ARG_DNS_MIN_TIME_BETWEEN_RESOLUTIONS_MS); + r->min_time_between_resolutions = + grpc_channel_arg_get_integer(period_arg, {1000, 0, INT_MAX}); + r->last_resolution_timestamp = -1; return &r->base; } diff --git a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc index d071c3ca42..2c798188d1 100644 --- a/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc +++ b/src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc @@ -19,11 +19,13 @@ #include <grpc/support/port_platform.h> #include <inttypes.h> -#include <string.h> +#include <climits> +#include <cstring> #include <grpc/support/alloc.h> #include <grpc/support/host_port.h> #include <grpc/support/string_util.h> +#include <grpc/support/time.h> #include "src/core/ext/filters/client_channel/lb_policy_registry.h" #include "src/core/ext/filters/client_channel/resolver_registry.h" @@ -65,13 +67,16 @@ typedef struct { grpc_channel_args** target_result; /** current (fully resolved) result */ grpc_channel_args* resolved_result; - /** retry timer */ - bool have_retry_timer; - grpc_timer retry_timer; - grpc_closure on_retry; + /** next resolution timer */ + bool have_next_resolution_timer; + grpc_timer next_resolution_timer; + grpc_closure next_resolution_closure; /** retry backoff state */ grpc_core::ManualConstructor<grpc_core::BackOff> backoff; - + /** min resolution period. Max one resolution will happen per period */ + grpc_millis min_time_between_resolutions; + /** when was the last resolution? -1 if no resolution has happened yet */ + grpc_millis last_resolution_timestamp; /** currently resolving addresses */ grpc_resolved_addresses* addresses; } dns_resolver; @@ -79,6 +84,7 @@ typedef struct { static void dns_destroy(grpc_resolver* r); static void dns_start_resolving_locked(dns_resolver* r); +static void maybe_start_resolving_locked(dns_resolver* r); static void dns_maybe_finish_next_locked(dns_resolver* r); static void dns_shutdown_locked(grpc_resolver* r); @@ -92,8 +98,8 @@ static const grpc_resolver_vtable dns_resolver_vtable = { static void dns_shutdown_locked(grpc_resolver* resolver) { dns_resolver* r = (dns_resolver*)resolver; - if (r->have_retry_timer) { - grpc_timer_cancel(&r->retry_timer); + if (r->have_next_resolution_timer) { + grpc_timer_cancel(&r->next_resolution_timer); } if (r->next_completion != nullptr) { *r->target_result = nullptr; @@ -106,7 +112,7 @@ static void dns_shutdown_locked(grpc_resolver* resolver) { static void dns_channel_saw_error_locked(grpc_resolver* resolver) { dns_resolver* r = (dns_resolver*)resolver; if (!r->resolving) { - dns_start_resolving_locked(r); + maybe_start_resolving_locked(r); } } @@ -118,23 +124,19 @@ static void dns_next_locked(grpc_resolver* resolver, r->next_completion = on_complete; r->target_result = target_result; if (r->resolved_version == 0 && !r->resolving) { - dns_start_resolving_locked(r); + maybe_start_resolving_locked(r); } else { dns_maybe_finish_next_locked(r); } } -static void dns_on_retry_timer_locked(void* arg, grpc_error* error) { +static void dns_on_next_resolution_timer_locked(void* arg, grpc_error* error) { dns_resolver* r = (dns_resolver*)arg; - - r->have_retry_timer = false; - if (error == GRPC_ERROR_NONE) { - if (!r->resolving) { - dns_start_resolving_locked(r); - } + r->have_next_resolution_timer = false; + if (error == GRPC_ERROR_NONE && !r->resolving) { + dns_start_resolving_locked(r); } - - GRPC_RESOLVER_UNREF(&r->base, "retry-timer"); + GRPC_RESOLVER_UNREF(&r->base, "next_resolution_timer"); } static void dns_on_resolved_locked(void* arg, grpc_error* error) { @@ -166,17 +168,16 @@ static void dns_on_resolved_locked(void* arg, grpc_error* error) { grpc_millis timeout = next_try - grpc_core::ExecCtx::Get()->Now(); gpr_log(GPR_INFO, "dns resolution failed (will retry): %s", grpc_error_string(error)); - GPR_ASSERT(!r->have_retry_timer); - r->have_retry_timer = true; - GRPC_RESOLVER_REF(&r->base, "retry-timer"); + GPR_ASSERT(!r->have_next_resolution_timer); + r->have_next_resolution_timer = true; + GRPC_RESOLVER_REF(&r->base, "next_resolution_timer"); if (timeout > 0) { gpr_log(GPR_DEBUG, "retrying in %" PRIdPTR " milliseconds", timeout); } else { gpr_log(GPR_DEBUG, "retrying immediately"); } - GRPC_CLOSURE_INIT(&r->on_retry, dns_on_retry_timer_locked, r, - grpc_combiner_scheduler(r->base.combiner)); - grpc_timer_init(&r->retry_timer, next_try, &r->on_retry); + grpc_timer_init(&r->next_resolution_timer, next_try, + &r->next_resolution_closure); } if (r->resolved_result != nullptr) { grpc_channel_args_destroy(r->resolved_result); @@ -189,6 +190,35 @@ static void dns_on_resolved_locked(void* arg, grpc_error* error) { GRPC_RESOLVER_UNREF(&r->base, "dns-resolving"); } +static void maybe_start_resolving_locked(dns_resolver* r) { + if (r->last_resolution_timestamp >= 0) { + const grpc_millis earliest_next_resolution = + r->last_resolution_timestamp + r->min_time_between_resolutions; + const grpc_millis ms_until_next_resolution = + earliest_next_resolution - grpc_core::ExecCtx::Get()->Now(); + if (ms_until_next_resolution > 0) { + const grpc_millis last_resolution_ago = + grpc_core::ExecCtx::Get()->Now() - r->last_resolution_timestamp; + gpr_log(GPR_DEBUG, + "In cooldown from last resolution (from %" PRIdPTR + " ms ago). Will resolve again in %" PRIdPTR " ms", + last_resolution_ago, ms_until_next_resolution); + if (!r->have_next_resolution_timer) { + r->have_next_resolution_timer = true; + GRPC_RESOLVER_REF(&r->base, "next_resolution_timer_cooldown"); + grpc_timer_init(&r->next_resolution_timer, ms_until_next_resolution, + &r->next_resolution_closure); + } + // TODO(dgq): remove the following two lines once Pick First stops + // discarding subchannels after selecting. + ++r->resolved_version; + dns_maybe_finish_next_locked(r); + return; + } + } + dns_start_resolving_locked(r); +} + static void dns_start_resolving_locked(dns_resolver* r) { GRPC_RESOLVER_REF(&r->base, "dns-resolving"); GPR_ASSERT(!r->resolving); @@ -199,6 +229,7 @@ static void dns_start_resolving_locked(dns_resolver* r) { GRPC_CLOSURE_CREATE(dns_on_resolved_locked, r, grpc_combiner_scheduler(r->base.combiner)), &r->addresses); + r->last_resolution_timestamp = grpc_core::ExecCtx::Get()->Now(); } static void dns_maybe_finish_next_locked(dns_resolver* r) { @@ -251,6 +282,14 @@ static grpc_resolver* dns_create(grpc_resolver_args* args, .set_jitter(GRPC_DNS_RECONNECT_JITTER) .set_max_backoff(GRPC_DNS_RECONNECT_MAX_BACKOFF_SECONDS * 1000); r->backoff.Init(grpc_core::BackOff(backoff_options)); + const grpc_arg* period_arg = grpc_channel_args_find( + args->args, GRPC_ARG_DNS_MIN_TIME_BETWEEN_RESOLUTIONS_MS); + r->min_time_between_resolutions = + grpc_channel_arg_get_integer(period_arg, {1000, 0, INT_MAX}); + r->last_resolution_timestamp = -1; + GRPC_CLOSURE_INIT(&r->next_resolution_closure, + dns_on_next_resolution_timer_locked, r, + grpc_combiner_scheduler(r->base.combiner)); return &r->base; } |