diff options
Diffstat (limited to 'src/core/ext/filters/client_channel/health/health_check_client.cc')
| -rw-r--r-- | src/core/ext/filters/client_channel/health/health_check_client.cc | 652 |
1 files changed, 652 insertions, 0 deletions
diff --git a/src/core/ext/filters/client_channel/health/health_check_client.cc b/src/core/ext/filters/client_channel/health/health_check_client.cc new file mode 100644 index 0000000000..587919596f --- /dev/null +++ b/src/core/ext/filters/client_channel/health/health_check_client.cc @@ -0,0 +1,652 @@ +/* + * + * 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. + * + */ + +#include <grpc/support/port_platform.h> + +#include <stdint.h> +#include <stdio.h> + +#include "src/core/ext/filters/client_channel/health/health_check_client.h" + +#include "pb_decode.h" +#include "pb_encode.h" +#include "src/core/ext/filters/client_channel/health/health.pb.h" +#include "src/core/lib/debug/trace.h" +#include "src/core/lib/gprpp/mutex_lock.h" +#include "src/core/lib/slice/slice_internal.h" +#include "src/core/lib/transport/error_utils.h" +#include "src/core/lib/transport/status_metadata.h" + +#define HEALTH_CHECK_INITIAL_CONNECT_BACKOFF_SECONDS 1 +#define HEALTH_CHECK_RECONNECT_BACKOFF_MULTIPLIER 1.6 +#define HEALTH_CHECK_RECONNECT_MAX_BACKOFF_SECONDS 120 +#define HEALTH_CHECK_RECONNECT_JITTER 0.2 + +grpc_core::TraceFlag grpc_health_check_client_trace(false, + "health_check_client"); + +namespace grpc_core { + +// +// HealthCheckClient +// + +HealthCheckClient::HealthCheckClient( + const char* service_name, + RefCountedPtr<ConnectedSubchannel> connected_subchannel, + grpc_pollset_set* interested_parties, + grpc_core::RefCountedPtr<grpc_core::channelz::SubchannelNode> channelz_node) + : InternallyRefCountedWithTracing<HealthCheckClient>( + &grpc_health_check_client_trace), + service_name_(service_name), + connected_subchannel_(std::move(connected_subchannel)), + interested_parties_(interested_parties), + channelz_node_(std::move(channelz_node)), + retry_backoff_( + BackOff::Options() + .set_initial_backoff( + HEALTH_CHECK_INITIAL_CONNECT_BACKOFF_SECONDS * 1000) + .set_multiplier(HEALTH_CHECK_RECONNECT_BACKOFF_MULTIPLIER) + .set_jitter(HEALTH_CHECK_RECONNECT_JITTER) + .set_max_backoff(HEALTH_CHECK_RECONNECT_MAX_BACKOFF_SECONDS * + 1000)) { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "created HealthCheckClient %p", this); + } + GRPC_CLOSURE_INIT(&retry_timer_callback_, OnRetryTimer, this, + grpc_schedule_on_exec_ctx); + gpr_mu_init(&mu_); + StartCall(); +} + +HealthCheckClient::~HealthCheckClient() { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "destroying HealthCheckClient %p", this); + } + GRPC_ERROR_UNREF(error_); + gpr_mu_destroy(&mu_); +} + +void HealthCheckClient::NotifyOnHealthChange(grpc_connectivity_state* state, + grpc_closure* closure) { + MutexLock lock(&mu_); + GPR_ASSERT(notify_state_ == nullptr); + if (*state != state_) { + *state = state_; + GRPC_CLOSURE_SCHED(closure, GRPC_ERROR_REF(error_)); + return; + } + notify_state_ = state; + on_health_changed_ = closure; +} + +void HealthCheckClient::SetHealthStatus(grpc_connectivity_state state, + grpc_error* error) { + MutexLock lock(&mu_); + SetHealthStatusLocked(state, error); +} + +void HealthCheckClient::SetHealthStatusLocked(grpc_connectivity_state state, + grpc_error* error) { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: setting state=%d error=%s", this, + state, grpc_error_string(error)); + } + if (notify_state_ != nullptr && *notify_state_ != state) { + *notify_state_ = state; + notify_state_ = nullptr; + GRPC_CLOSURE_SCHED(on_health_changed_, GRPC_ERROR_REF(error)); + on_health_changed_ = nullptr; + } + state_ = state; + GRPC_ERROR_UNREF(error_); + error_ = error; +} + +void HealthCheckClient::Orphan() { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: shutting down", this); + } + { + MutexLock lock(&mu_); + if (on_health_changed_ != nullptr) { + *notify_state_ = GRPC_CHANNEL_SHUTDOWN; + notify_state_ = nullptr; + GRPC_CLOSURE_SCHED(on_health_changed_, GRPC_ERROR_NONE); + on_health_changed_ = nullptr; + } + shutting_down_ = true; + call_state_.reset(); + if (retry_timer_callback_pending_) { + grpc_timer_cancel(&retry_timer_); + } + } + Unref(DEBUG_LOCATION, "orphan"); +} + +void HealthCheckClient::StartCall() { + MutexLock lock(&mu_); + StartCallLocked(); +} + +void HealthCheckClient::StartCallLocked() { + if (shutting_down_) return; + GPR_ASSERT(call_state_ == nullptr); + SetHealthStatusLocked(GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE); + call_state_ = MakeOrphanable<CallState>(Ref(), interested_parties_); + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: created CallState %p", this, + call_state_.get()); + } + call_state_->StartCall(); +} + +void HealthCheckClient::StartRetryTimer() { + MutexLock lock(&mu_); + SetHealthStatusLocked( + GRPC_CHANNEL_TRANSIENT_FAILURE, + GRPC_ERROR_CREATE_FROM_STATIC_STRING( + "health check call failed; will retry after backoff")); + grpc_millis next_try = retry_backoff_.NextAttemptTime(); + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: health check call lost...", this); + grpc_millis timeout = next_try - ExecCtx::Get()->Now(); + if (timeout > 0) { + gpr_log(GPR_INFO, + "HealthCheckClient %p: ... will retry in %" PRId64 "ms.", this, + timeout); + } else { + gpr_log(GPR_INFO, "HealthCheckClient %p: ... retrying immediately.", + this); + } + } + // Ref for callback, tracked manually. + Ref(DEBUG_LOCATION, "health_retry_timer").release(); + retry_timer_callback_pending_ = true; + grpc_timer_init(&retry_timer_, next_try, &retry_timer_callback_); +} + +void HealthCheckClient::OnRetryTimer(void* arg, grpc_error* error) { + HealthCheckClient* self = static_cast<HealthCheckClient*>(arg); + { + MutexLock lock(&self->mu_); + self->retry_timer_callback_pending_ = false; + if (!self->shutting_down_ && error == GRPC_ERROR_NONE && + self->call_state_ == nullptr) { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: restarting health check call", + self); + } + self->StartCallLocked(); + } + } + self->Unref(DEBUG_LOCATION, "health_retry_timer"); +} + +// +// protobuf helpers +// + +namespace { + +void EncodeRequest(const char* service_name, + ManualConstructor<SliceBufferByteStream>* send_message) { + grpc_health_v1_HealthCheckRequest request_struct; + request_struct.has_service = true; + snprintf(request_struct.service, sizeof(request_struct.service), "%s", + service_name); + pb_ostream_t ostream; + memset(&ostream, 0, sizeof(ostream)); + pb_encode(&ostream, grpc_health_v1_HealthCheckRequest_fields, + &request_struct); + grpc_slice request_slice = GRPC_SLICE_MALLOC(ostream.bytes_written); + ostream = pb_ostream_from_buffer(GRPC_SLICE_START_PTR(request_slice), + GRPC_SLICE_LENGTH(request_slice)); + GPR_ASSERT(pb_encode(&ostream, grpc_health_v1_HealthCheckRequest_fields, + &request_struct) != 0); + grpc_slice_buffer slice_buffer; + grpc_slice_buffer_init(&slice_buffer); + grpc_slice_buffer_add(&slice_buffer, request_slice); + send_message->Init(&slice_buffer, 0); + grpc_slice_buffer_destroy_internal(&slice_buffer); +} + +// Returns true if healthy. +// If there was an error parsing the response, sets *error and returns false. +bool DecodeResponse(grpc_slice_buffer* slice_buffer, grpc_error** error) { + // If message is empty, assume unhealthy. + if (slice_buffer->length == 0) { + *error = + GRPC_ERROR_CREATE_FROM_STATIC_STRING("health check response was empty"); + return false; + } + // Concatenate the slices to form a single string. + UniquePtr<uint8_t> recv_message_deleter; + uint8_t* recv_message; + if (slice_buffer->count == 1) { + recv_message = GRPC_SLICE_START_PTR(slice_buffer->slices[0]); + } else { + recv_message = static_cast<uint8_t*>(gpr_malloc(slice_buffer->length)); + recv_message_deleter.reset(recv_message); + size_t offset = 0; + for (size_t i = 0; i < slice_buffer->count; ++i) { + memcpy(recv_message + offset, + GRPC_SLICE_START_PTR(slice_buffer->slices[i]), + GRPC_SLICE_LENGTH(slice_buffer->slices[i])); + offset += GRPC_SLICE_LENGTH(slice_buffer->slices[i]); + } + } + // Deserialize message. + grpc_health_v1_HealthCheckResponse response_struct; + pb_istream_t istream = + pb_istream_from_buffer(recv_message, slice_buffer->length); + if (!pb_decode(&istream, grpc_health_v1_HealthCheckResponse_fields, + &response_struct)) { + // Can't parse message; assume unhealthy. + *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING( + "cannot parse health check response"); + return false; + } + if (!response_struct.has_status) { + // Field not present; assume unhealthy. + *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING( + "status field not present in health check response"); + return false; + } + return response_struct.status == + grpc_health_v1_HealthCheckResponse_ServingStatus_SERVING; +} + +} // namespace + +// +// HealthCheckClient::CallState +// + +HealthCheckClient::CallState::CallState( + RefCountedPtr<HealthCheckClient> health_check_client, + grpc_pollset_set* interested_parties) + : InternallyRefCountedWithTracing<CallState>( + &grpc_health_check_client_trace), + health_check_client_(std::move(health_check_client)), + pollent_(grpc_polling_entity_create_from_pollset_set(interested_parties)), + arena_(gpr_arena_create(health_check_client_->connected_subchannel_ + ->GetInitialCallSizeEstimate(0))), + payload_(context_) { + grpc_call_combiner_init(&call_combiner_); + gpr_atm_rel_store(&seen_response_, static_cast<gpr_atm>(0)); +} + +HealthCheckClient::CallState::~CallState() { + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, "HealthCheckClient %p: destroying CallState %p", + health_check_client_.get(), this); + } + if (call_ != nullptr) GRPC_SUBCHANNEL_CALL_UNREF(call_, "call_ended"); + for (size_t i = 0; i < GRPC_CONTEXT_COUNT; i++) { + if (context_[i].destroy != nullptr) { + context_[i].destroy(context_[i].value); + } + } + // Unset the call combiner cancellation closure. This has the + // effect of scheduling the previously set cancellation closure, if + // any, so that it can release any internal references it may be + // holding to the call stack. Also flush the closures on exec_ctx so that + // filters that schedule cancel notification closures on exec_ctx do not + // need to take a ref of the call stack to guarantee closure liveness. + grpc_call_combiner_set_notify_on_cancel(&call_combiner_, nullptr); + grpc_core::ExecCtx::Get()->Flush(); + grpc_call_combiner_destroy(&call_combiner_); + gpr_arena_destroy(arena_); +} + +void HealthCheckClient::CallState::Orphan() { + grpc_call_combiner_cancel(&call_combiner_, GRPC_ERROR_CANCELLED); + Cancel(); +} + +void HealthCheckClient::CallState::StartCall() { + ConnectedSubchannel::CallArgs args = { + &pollent_, + GRPC_MDSTR_SLASH_GRPC_DOT_HEALTH_DOT_V1_DOT_HEALTH_SLASH_WATCH, + gpr_now(GPR_CLOCK_MONOTONIC), // start_time + GRPC_MILLIS_INF_FUTURE, // deadline + arena_, + context_, + &call_combiner_, + 0, // parent_data_size + }; + grpc_error* error = + health_check_client_->connected_subchannel_->CreateCall(args, &call_); + if (error != GRPC_ERROR_NONE) { + gpr_log(GPR_ERROR, + "HealthCheckClient %p CallState %p: error creating health " + "checking call on subchannel (%s); will retry", + health_check_client_.get(), this, grpc_error_string(error)); + GRPC_ERROR_UNREF(error); + // Schedule instead of running directly, since we must not be + // holding health_check_client_->mu_ when CallEnded() is called. + Ref(DEBUG_LOCATION, "call_end_closure").release(); + GRPC_CLOSURE_SCHED( + GRPC_CLOSURE_INIT(&batch_.handler_private.closure, CallEndedRetry, this, + grpc_schedule_on_exec_ctx), + GRPC_ERROR_NONE); + return; + } + // Initialize payload and batch. + memset(&batch_, 0, sizeof(batch_)); + payload_.context = context_; + batch_.payload = &payload_; + // on_complete callback takes ref, handled manually. + Ref(DEBUG_LOCATION, "on_complete").release(); + batch_.on_complete = GRPC_CLOSURE_INIT(&on_complete_, OnComplete, this, + grpc_schedule_on_exec_ctx); + // Add send_initial_metadata op. + grpc_metadata_batch_init(&send_initial_metadata_); + error = grpc_metadata_batch_add_head( + &send_initial_metadata_, &path_metadata_storage_, + grpc_mdelem_from_slices( + GRPC_MDSTR_PATH, + GRPC_MDSTR_SLASH_GRPC_DOT_HEALTH_DOT_V1_DOT_HEALTH_SLASH_WATCH)); + GPR_ASSERT(error == GRPC_ERROR_NONE); + payload_.send_initial_metadata.send_initial_metadata = + &send_initial_metadata_; + payload_.send_initial_metadata.send_initial_metadata_flags = 0; + payload_.send_initial_metadata.peer_string = nullptr; + batch_.send_initial_metadata = true; + // Add send_message op. + EncodeRequest(health_check_client_->service_name_, &send_message_); + payload_.send_message.send_message.reset(send_message_.get()); + batch_.send_message = true; + // Add send_trailing_metadata op. + grpc_metadata_batch_init(&send_trailing_metadata_); + payload_.send_trailing_metadata.send_trailing_metadata = + &send_trailing_metadata_; + batch_.send_trailing_metadata = true; + // Add recv_initial_metadata op. + grpc_metadata_batch_init(&recv_initial_metadata_); + payload_.recv_initial_metadata.recv_initial_metadata = + &recv_initial_metadata_; + payload_.recv_initial_metadata.recv_flags = nullptr; + payload_.recv_initial_metadata.trailing_metadata_available = nullptr; + payload_.recv_initial_metadata.peer_string = nullptr; + // recv_initial_metadata_ready callback takes ref, handled manually. + Ref(DEBUG_LOCATION, "recv_initial_metadata_ready").release(); + payload_.recv_initial_metadata.recv_initial_metadata_ready = + GRPC_CLOSURE_INIT(&recv_initial_metadata_ready_, RecvInitialMetadataReady, + this, grpc_schedule_on_exec_ctx); + batch_.recv_initial_metadata = true; + // Add recv_message op. + payload_.recv_message.recv_message = &recv_message_; + // recv_message callback takes ref, handled manually. + Ref(DEBUG_LOCATION, "recv_message_ready").release(); + payload_.recv_message.recv_message_ready = GRPC_CLOSURE_INIT( + &recv_message_ready_, RecvMessageReady, this, grpc_schedule_on_exec_ctx); + batch_.recv_message = true; + // Start batch. + StartBatch(&batch_); + // Initialize recv_trailing_metadata batch. + memset(&recv_trailing_metadata_batch_, 0, + sizeof(recv_trailing_metadata_batch_)); + recv_trailing_metadata_batch_.payload = &payload_; + // Add recv_trailing_metadata op. + grpc_metadata_batch_init(&recv_trailing_metadata_); + payload_.recv_trailing_metadata.recv_trailing_metadata = + &recv_trailing_metadata_; + payload_.recv_trailing_metadata.collect_stats = &collect_stats_; + // This callback signals the end of the call, so it relies on the + // initial ref instead of taking a new ref. When it's invoked, the + // initial ref is released. + payload_.recv_trailing_metadata.recv_trailing_metadata_ready = + GRPC_CLOSURE_INIT(&recv_trailing_metadata_ready_, + RecvTrailingMetadataReady, this, + grpc_schedule_on_exec_ctx); + recv_trailing_metadata_batch_.recv_trailing_metadata = true; + // Start recv_trailing_metadata batch. + StartBatch(&recv_trailing_metadata_batch_); +} + +void HealthCheckClient::CallState::StartBatchInCallCombiner(void* arg, + grpc_error* error) { + grpc_transport_stream_op_batch* batch = + static_cast<grpc_transport_stream_op_batch*>(arg); + grpc_subchannel_call* call = + static_cast<grpc_subchannel_call*>(batch->handler_private.extra_arg); + grpc_subchannel_call_process_op(call, batch); +} + +void HealthCheckClient::CallState::StartBatch( + grpc_transport_stream_op_batch* batch) { + batch->handler_private.extra_arg = call_; + GRPC_CLOSURE_INIT(&batch->handler_private.closure, StartBatchInCallCombiner, + batch, grpc_schedule_on_exec_ctx); + GRPC_CALL_COMBINER_START(&call_combiner_, &batch->handler_private.closure, + GRPC_ERROR_NONE, "start_subchannel_batch"); +} + +void HealthCheckClient::CallState::OnCancelComplete(void* arg, + grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "health_cancel"); + self->Unref(DEBUG_LOCATION, "cancel"); +} + +void HealthCheckClient::CallState::StartCancel(void* arg, grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + auto* batch = grpc_make_transport_stream_op( + GRPC_CLOSURE_CREATE(OnCancelComplete, self, grpc_schedule_on_exec_ctx)); + batch->cancel_stream = true; + batch->payload->cancel_stream.cancel_error = GRPC_ERROR_CANCELLED; + grpc_subchannel_call_process_op(self->call_, batch); +} + +void HealthCheckClient::CallState::Cancel() { + if (call_ != nullptr) { + Ref(DEBUG_LOCATION, "cancel").release(); + GRPC_CALL_COMBINER_START( + &call_combiner_, + GRPC_CLOSURE_CREATE(StartCancel, this, grpc_schedule_on_exec_ctx), + GRPC_ERROR_NONE, "health_cancel"); + } +} + +void HealthCheckClient::CallState::OnComplete(void* arg, grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "on_complete"); + grpc_metadata_batch_destroy(&self->send_initial_metadata_); + grpc_metadata_batch_destroy(&self->send_trailing_metadata_); + self->Unref(DEBUG_LOCATION, "on_complete"); +} + +void HealthCheckClient::CallState::RecvInitialMetadataReady(void* arg, + grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "recv_initial_metadata_ready"); + grpc_metadata_batch_destroy(&self->recv_initial_metadata_); + self->Unref(DEBUG_LOCATION, "recv_initial_metadata_ready"); +} + +void HealthCheckClient::CallState::DoneReadingRecvMessage(grpc_error* error) { + recv_message_.reset(); + if (error != GRPC_ERROR_NONE) { + GRPC_ERROR_UNREF(error); + Cancel(); + grpc_slice_buffer_destroy_internal(&recv_message_buffer_); + Unref(DEBUG_LOCATION, "recv_message_ready"); + return; + } + const bool healthy = DecodeResponse(&recv_message_buffer_, &error); + const grpc_connectivity_state state = + healthy ? GRPC_CHANNEL_READY : GRPC_CHANNEL_TRANSIENT_FAILURE; + if (error == GRPC_ERROR_NONE && !healthy) { + error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("backend unhealthy"); + } + health_check_client_->SetHealthStatus(state, error); + gpr_atm_rel_store(&seen_response_, static_cast<gpr_atm>(1)); + grpc_slice_buffer_destroy_internal(&recv_message_buffer_); + // Start another recv_message batch. + // This re-uses the ref we're holding. + // Note: Can't just reuse batch_ here, since we don't know that all + // callbacks from the original batch have completed yet. + memset(&recv_message_batch_, 0, sizeof(recv_message_batch_)); + recv_message_batch_.payload = &payload_; + payload_.recv_message.recv_message = &recv_message_; + payload_.recv_message.recv_message_ready = GRPC_CLOSURE_INIT( + &recv_message_ready_, RecvMessageReady, this, grpc_schedule_on_exec_ctx); + recv_message_batch_.recv_message = true; + StartBatch(&recv_message_batch_); +} + +grpc_error* HealthCheckClient::CallState::PullSliceFromRecvMessage() { + grpc_slice slice; + grpc_error* error = recv_message_->Pull(&slice); + if (error == GRPC_ERROR_NONE) { + grpc_slice_buffer_add(&recv_message_buffer_, slice); + } + return error; +} + +void HealthCheckClient::CallState::ContinueReadingRecvMessage() { + while (recv_message_->Next(SIZE_MAX, &recv_message_ready_)) { + grpc_error* error = PullSliceFromRecvMessage(); + if (error != GRPC_ERROR_NONE) { + DoneReadingRecvMessage(error); + return; + } + if (recv_message_buffer_.length == recv_message_->length()) { + DoneReadingRecvMessage(GRPC_ERROR_NONE); + break; + } + } +} + +void HealthCheckClient::CallState::OnByteStreamNext(void* arg, + grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + if (error != GRPC_ERROR_NONE) { + self->DoneReadingRecvMessage(GRPC_ERROR_REF(error)); + return; + } + error = self->PullSliceFromRecvMessage(); + if (error != GRPC_ERROR_NONE) { + self->DoneReadingRecvMessage(error); + return; + } + if (self->recv_message_buffer_.length == self->recv_message_->length()) { + self->DoneReadingRecvMessage(GRPC_ERROR_NONE); + } else { + self->ContinueReadingRecvMessage(); + } +} + +void HealthCheckClient::CallState::RecvMessageReady(void* arg, + grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "recv_message_ready"); + if (self->recv_message_ == nullptr) { + self->Unref(DEBUG_LOCATION, "recv_message_ready"); + return; + } + grpc_slice_buffer_init(&self->recv_message_buffer_); + GRPC_CLOSURE_INIT(&self->recv_message_ready_, OnByteStreamNext, self, + grpc_schedule_on_exec_ctx); + self->ContinueReadingRecvMessage(); + // Ref will continue to be held until we finish draining the byte stream. +} + +void HealthCheckClient::CallState::RecvTrailingMetadataReady( + void* arg, grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + GRPC_CALL_COMBINER_STOP(&self->call_combiner_, + "recv_trailing_metadata_ready"); + // Get call status. + grpc_status_code status = GRPC_STATUS_UNKNOWN; + if (error != GRPC_ERROR_NONE) { + grpc_error_get_status(error, GRPC_MILLIS_INF_FUTURE, &status, + nullptr /* slice */, nullptr /* http_error */, + nullptr /* error_string */); + } else if (self->recv_trailing_metadata_.idx.named.grpc_status != nullptr) { + status = grpc_get_status_code_from_metadata( + self->recv_trailing_metadata_.idx.named.grpc_status->md); + } + if (grpc_health_check_client_trace.enabled()) { + gpr_log(GPR_INFO, + "HealthCheckClient %p CallState %p: health watch failed with " + "status %d", + self->health_check_client_.get(), self, status); + } + // Clean up. + grpc_metadata_batch_destroy(&self->recv_trailing_metadata_); + // For status UNIMPLEMENTED, give up and assume always healthy. + bool retry = true; + if (status == GRPC_STATUS_UNIMPLEMENTED) { + static const char kErrorMessage[] = + "health checking Watch method returned UNIMPLEMENTED; " + "disabling health checks but assuming server is healthy"; + gpr_log(GPR_ERROR, kErrorMessage); + if (self->health_check_client_->channelz_node_ != nullptr) { + self->health_check_client_->channelz_node_->AddTraceEvent( + channelz::ChannelTrace::Error, + grpc_slice_from_static_string(kErrorMessage)); + } + self->health_check_client_->SetHealthStatus(GRPC_CHANNEL_READY, + GRPC_ERROR_NONE); + retry = false; + } + self->CallEnded(retry); +} + +void HealthCheckClient::CallState::CallEndedRetry(void* arg, + grpc_error* error) { + HealthCheckClient::CallState* self = + static_cast<HealthCheckClient::CallState*>(arg); + self->CallEnded(true /* retry */); + self->Unref(DEBUG_LOCATION, "call_end_closure"); +} + +void HealthCheckClient::CallState::CallEnded(bool retry) { + // If this CallState is still in use, this call ended because of a failure, + // so we need to stop using it and optionally create a new one. + // Otherwise, we have deliberately ended this call, and no further action + // is required. + if (this == health_check_client_->call_state_.get()) { + health_check_client_->call_state_.reset(); + if (retry) { + GPR_ASSERT(!health_check_client_->shutting_down_); + if (static_cast<bool>(gpr_atm_acq_load(&seen_response_))) { + // If the call fails after we've gotten a successful response, reset + // the backoff and restart the call immediately. + health_check_client_->retry_backoff_.Reset(); + health_check_client_->StartCall(); + } else { + // If the call failed without receiving any messages, retry later. + health_check_client_->StartRetryTimer(); + } + } + } + Unref(DEBUG_LOCATION, "call_ended"); +} + +} // namespace grpc_core |