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Diffstat (limited to 'src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc')
-rw-r--r--src/core/ext/filters/client_channel/resolver/dns/native/dns_resolver.cc89
1 files changed, 64 insertions, 25 deletions
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;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-03 14:57:28 +0000