mirror of https://github.com/grpc/grpc.git
Mark D. Roth
6 months ago
commit
b289c399fe
188 changed files with 8103 additions and 1974 deletions
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//
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// Copyright 2015 gRPC authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#ifndef GRPC_SRC_CORE_CLIENT_CHANNEL_CLIENT_CHANNEL_H |
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#define GRPC_SRC_CORE_CLIENT_CHANNEL_CLIENT_CHANNEL_H |
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#include <grpc/support/port_platform.h> |
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#include "absl/status/status.h" |
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#include "absl/status/statusor.h" |
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#include "absl/strings/string_view.h" |
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#include "src/core/client_channel/client_channel_factory.h" |
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#include "src/core/client_channel/config_selector.h" |
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#include "src/core/client_channel/subchannel.h" |
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#include "src/core/ext/filters/channel_idle/idle_filter_state.h" |
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#include "src/core/lib/gprpp/single_set_ptr.h" |
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#include "src/core/lib/promise/observable.h" |
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#include "src/core/lib/surface/channel.h" |
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#include "src/core/lib/transport/metadata.h" |
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#include "src/core/load_balancing/lb_policy.h" |
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#include "src/core/resolver/resolver.h" |
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#include "src/core/service_config/service_config.h" |
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namespace grpc_core { |
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class ClientChannel : public Channel { |
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public: |
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using PickerObservable = |
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Observable<RefCountedPtr<LoadBalancingPolicy::SubchannelPicker>>; |
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class CallDestinationFactory { |
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public: |
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struct RawPointerChannelArgTag {}; |
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static absl::string_view ChannelArgName() { |
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return "grpc.internal.client_channel_call_destination"; |
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} |
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virtual RefCountedPtr<UnstartedCallDestination> CreateCallDestination( |
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PickerObservable) = 0; |
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protected: |
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~CallDestinationFactory() = default; |
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}; |
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static absl::StatusOr<OrphanablePtr<Channel>> Create( |
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std::string target, ChannelArgs channel_args); |
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// Do not instantiate directly -- use Create() instead.
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ClientChannel(std::string target_uri, ChannelArgs args, |
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std::string uri_to_resolve, |
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RefCountedPtr<ServiceConfig> default_service_config, |
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ClientChannelFactory* client_channel_factory, |
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CallDestinationFactory* call_destination_factory); |
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~ClientChannel() override; |
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void Orphan() override; |
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grpc_call* CreateCall(grpc_call* parent_call, uint32_t propagation_mask, |
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grpc_completion_queue* cq, |
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grpc_pollset_set* /*pollset_set_alternative*/, |
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Slice path, absl::optional<Slice> authority, |
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Timestamp deadline, bool registered_method) override; |
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CallInitiator CreateCall(ClientMetadataHandle client_initial_metadata); |
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grpc_event_engine::experimental::EventEngine* event_engine() const override { |
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return event_engine_.get(); |
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} |
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// TODO(ctiller): lame channels
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bool IsLame() const override { return false; } |
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bool SupportsConnectivityWatcher() const override { return true; } |
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// Returns the current connectivity state. If try_to_connect is true,
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// triggers a connection attempt if not already connected.
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grpc_connectivity_state CheckConnectivityState(bool try_to_connect) override; |
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void WatchConnectivityState(grpc_connectivity_state last_observed_state, |
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Timestamp deadline, grpc_completion_queue* cq, |
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void* tag) override; |
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// Starts and stops a connectivity watch. The watcher will be initially
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// notified as soon as the state changes from initial_state and then on
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// every subsequent state change until either the watch is stopped or
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// it is notified that the state has changed to SHUTDOWN.
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//
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// This is intended to be used when starting watches from code inside of
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// C-core (e.g., for a nested control plane channel for things like xds).
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void AddConnectivityWatcher( |
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grpc_connectivity_state initial_state, |
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OrphanablePtr<AsyncConnectivityStateWatcherInterface> watcher) override; |
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void RemoveConnectivityWatcher( |
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AsyncConnectivityStateWatcherInterface* watcher) override; |
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void GetInfo(const grpc_channel_info* channel_info) override; |
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void ResetConnectionBackoff() override; |
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void Ping(grpc_completion_queue* cq, void* tag) override; |
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// Flag that this object gets stored in channel args as a raw pointer.
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struct RawPointerChannelArgTag {}; |
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static absl::string_view ChannelArgName() { |
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return "grpc.internal.client_channel"; |
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} |
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private: |
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class ClientChannelControlHelper; |
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class ResolverResultHandler; |
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class SubchannelWrapper; |
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void CreateResolverLocked() ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void DestroyResolverAndLbPolicyLocked() |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void TryToConnectLocked() ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void OnResolverResultChangedLocked(Resolver::Result result) |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void OnResolverErrorLocked(absl::Status status) |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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absl::Status CreateOrUpdateLbPolicyLocked( |
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RefCountedPtr<LoadBalancingPolicy::Config> lb_policy_config, |
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const absl::optional<std::string>& health_check_service_name, |
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Resolver::Result result) ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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OrphanablePtr<LoadBalancingPolicy> CreateLbPolicyLocked( |
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const ChannelArgs& args) ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void UpdateServiceConfigInControlPlaneLocked( |
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RefCountedPtr<ServiceConfig> service_config, |
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RefCountedPtr<ConfigSelector> config_selector, std::string lb_policy_name) |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void UpdateServiceConfigInDataPlaneLocked() |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void UpdateStateLocked(grpc_connectivity_state state, |
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const absl::Status& status, const char* reason) |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void UpdateStateAndPickerLocked( |
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grpc_connectivity_state state, const absl::Status& status, |
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const char* reason, |
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RefCountedPtr<LoadBalancingPolicy::SubchannelPicker> picker) |
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ABSL_EXCLUSIVE_LOCKS_REQUIRED(*work_serializer_); |
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void StartIdleTimer(); |
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// Applies service config settings from config_selector to the call.
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// May modify call context and client_initial_metadata.
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absl::Status ApplyServiceConfigToCall( |
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ConfigSelector& config_selector, |
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ClientMetadata& client_initial_metadata) const; |
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const ChannelArgs channel_args_; |
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const std::shared_ptr<grpc_event_engine::experimental::EventEngine> |
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event_engine_; |
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const std::string uri_to_resolve_; |
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const size_t service_config_parser_index_; |
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const RefCountedPtr<ServiceConfig> default_service_config_; |
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ClientChannelFactory* const client_channel_factory_; |
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const std::string default_authority_; |
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channelz::ChannelNode* const channelz_node_; |
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GlobalStatsPluginRegistry::StatsPluginGroup stats_plugin_group_; |
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//
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// Idleness state.
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//
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const Duration idle_timeout_; |
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IdleFilterState idle_state_{false}; |
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SingleSetPtr<Activity, typename ActivityPtr::deleter_type> idle_activity_; |
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//
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// Fields related to name resolution.
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//
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struct ResolverDataForCalls { |
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RefCountedPtr<ConfigSelector> config_selector; |
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RefCountedPtr<UnstartedCallDestination> call_destination; |
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}; |
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Observable<absl::StatusOr<ResolverDataForCalls>> resolver_data_for_calls_; |
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//
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// Fields related to LB picks.
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//
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PickerObservable picker_; |
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const RefCountedPtr<UnstartedCallDestination> call_destination_; |
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//
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// Fields used in the control plane. Guarded by work_serializer.
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//
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std::shared_ptr<WorkSerializer> work_serializer_; |
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ConnectivityStateTracker state_tracker_ ABSL_GUARDED_BY(*work_serializer_); |
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OrphanablePtr<Resolver> resolver_ ABSL_GUARDED_BY(*work_serializer_); |
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bool previous_resolution_contained_addresses_ |
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ABSL_GUARDED_BY(*work_serializer_) = false; |
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RefCountedPtr<ServiceConfig> saved_service_config_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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RefCountedPtr<ConfigSelector> saved_config_selector_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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OrphanablePtr<LoadBalancingPolicy> lb_policy_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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RefCountedPtr<SubchannelPoolInterface> subchannel_pool_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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// The number of SubchannelWrapper instances referencing a given Subchannel.
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std::map<Subchannel*, int> subchannel_refcount_map_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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// The set of SubchannelWrappers that currently exist.
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// No need to hold a ref, since the set is updated in the control-plane
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// work_serializer when the SubchannelWrappers are created and destroyed.
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absl::flat_hash_set<SubchannelWrapper*> subchannel_wrappers_ |
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ABSL_GUARDED_BY(*work_serializer_); |
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int keepalive_time_ ABSL_GUARDED_BY(*work_serializer_) = -1; |
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absl::Status disconnect_error_ ABSL_GUARDED_BY(*work_serializer_); |
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//
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// Fields accessed via GetChannelInfo().
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//
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Mutex info_mu_; |
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std::string info_lb_policy_name_ ABSL_GUARDED_BY(info_mu_); |
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std::string info_service_config_json_ ABSL_GUARDED_BY(info_mu_); |
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}; |
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} // namespace grpc_core
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#endif // GRPC_SRC_CORE_CLIENT_CHANNEL_CLIENT_CHANNEL_H
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@ -0,0 +1,335 @@ |
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// Copyright 2024 gRPC authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include "src/core/client_channel/load_balanced_call_destination.h" |
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#include "src/core/client_channel/client_channel.h" |
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#include "src/core/client_channel/client_channel_internal.h" |
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#include "src/core/client_channel/subchannel.h" |
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#include "src/core/lib/channel/status_util.h" |
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#include "src/core/lib/promise/loop.h" |
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#include "src/core/telemetry/call_tracer.h" |
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namespace grpc_core { |
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// Defined in legacy client channel filter.
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// TODO(roth): Move these here when we remove the legacy filter.
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extern TraceFlag grpc_client_channel_trace; |
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extern TraceFlag grpc_client_channel_call_trace; |
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extern TraceFlag grpc_client_channel_lb_call_trace; |
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namespace { |
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class LbMetadata : public LoadBalancingPolicy::MetadataInterface { |
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public: |
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explicit LbMetadata(grpc_metadata_batch* batch) : batch_(batch) {} |
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void Add(absl::string_view key, absl::string_view value) override { |
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if (batch_ == nullptr) return; |
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// Gross, egregious hack to support legacy grpclb behavior.
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// TODO(ctiller): Use a promise context for this once that plumbing is done.
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if (key == GrpcLbClientStatsMetadata::key()) { |
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batch_->Set( |
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GrpcLbClientStatsMetadata(), |
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const_cast<GrpcLbClientStats*>( |
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reinterpret_cast<const GrpcLbClientStats*>(value.data()))); |
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return; |
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} |
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batch_->Append(key, Slice::FromStaticString(value), |
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[key](absl::string_view error, const Slice& value) { |
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gpr_log(GPR_ERROR, "%s", |
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absl::StrCat(error, " key:", key, |
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" value:", value.as_string_view()) |
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.c_str()); |
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}); |
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} |
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std::vector<std::pair<std::string, std::string>> TestOnlyCopyToVector() |
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override { |
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if (batch_ == nullptr) return {}; |
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Encoder encoder; |
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batch_->Encode(&encoder); |
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return encoder.Take(); |
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} |
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absl::optional<absl::string_view> Lookup(absl::string_view key, |
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std::string* buffer) const override { |
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if (batch_ == nullptr) return absl::nullopt; |
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return batch_->GetStringValue(key, buffer); |
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} |
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private: |
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class Encoder { |
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public: |
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void Encode(const Slice& key, const Slice& value) { |
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out_.emplace_back(std::string(key.as_string_view()), |
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std::string(value.as_string_view())); |
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} |
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template <class Which> |
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void Encode(Which, const typename Which::ValueType& value) { |
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auto value_slice = Which::Encode(value); |
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out_.emplace_back(std::string(Which::key()), |
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std::string(value_slice.as_string_view())); |
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} |
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void Encode(GrpcTimeoutMetadata, |
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const typename GrpcTimeoutMetadata::ValueType&) {} |
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void Encode(HttpPathMetadata, const Slice&) {} |
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void Encode(HttpMethodMetadata, |
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const typename HttpMethodMetadata::ValueType&) {} |
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std::vector<std::pair<std::string, std::string>> Take() { |
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return std::move(out_); |
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} |
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private: |
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std::vector<std::pair<std::string, std::string>> out_; |
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}; |
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grpc_metadata_batch* batch_; |
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}; |
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void MaybeCreateCallAttemptTracer(bool is_transparent_retry) { |
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auto* call_tracer = MaybeGetContext<ClientCallTracer>(); |
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if (call_tracer == nullptr) return; |
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auto* tracer = call_tracer->StartNewAttempt(is_transparent_retry); |
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SetContext<CallTracerInterface>(tracer); |
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} |
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class LbCallState : public ClientChannelLbCallState { |
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public: |
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void* Alloc(size_t size) override { return GetContext<Arena>()->Alloc(size); } |
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// Internal API to allow first-party LB policies to access per-call
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// attributes set by the ConfigSelector.
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ServiceConfigCallData::CallAttributeInterface* GetCallAttribute( |
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UniqueTypeName type) const override { |
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auto* service_config_call_data = GetContext<ServiceConfigCallData>(); |
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return service_config_call_data->GetCallAttribute(type); |
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} |
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ClientCallTracer::CallAttemptTracer* GetCallAttemptTracer() const override { |
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auto* legacy_context = GetContext<grpc_call_context_element>(); |
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return static_cast<ClientCallTracer::CallAttemptTracer*>( |
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legacy_context[GRPC_CONTEXT_CALL_TRACER].value); |
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} |
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}; |
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// TODO(roth): Remove this in favor of the gprpp Match() function once
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// we can do that without breaking lock annotations.
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template <typename T> |
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T HandlePickResult( |
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LoadBalancingPolicy::PickResult* result, |
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std::function<T(LoadBalancingPolicy::PickResult::Complete*)> complete_func, |
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std::function<T(LoadBalancingPolicy::PickResult::Queue*)> queue_func, |
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std::function<T(LoadBalancingPolicy::PickResult::Fail*)> fail_func, |
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std::function<T(LoadBalancingPolicy::PickResult::Drop*)> drop_func) { |
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auto* complete_pick = |
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absl::get_if<LoadBalancingPolicy::PickResult::Complete>(&result->result); |
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if (complete_pick != nullptr) { |
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return complete_func(complete_pick); |
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} |
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auto* queue_pick = |
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absl::get_if<LoadBalancingPolicy::PickResult::Queue>(&result->result); |
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if (queue_pick != nullptr) { |
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return queue_func(queue_pick); |
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} |
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auto* fail_pick = |
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absl::get_if<LoadBalancingPolicy::PickResult::Fail>(&result->result); |
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if (fail_pick != nullptr) { |
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return fail_func(fail_pick); |
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} |
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auto* drop_pick = |
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absl::get_if<LoadBalancingPolicy::PickResult::Drop>(&result->result); |
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CHECK(drop_pick != nullptr); |
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return drop_func(drop_pick); |
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} |
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// Does an LB pick for a call. Returns one of the following things:
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// - Continue{}, meaning to queue the pick
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// - a non-OK status, meaning to fail the call
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// - a call destination, meaning that the pick is complete
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// When the pick is complete, pushes client_initial_metadata onto
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// call_initiator. Also adds the subchannel call tracker (if any) to
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// context.
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LoopCtl<absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>> PickSubchannel( |
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LoadBalancingPolicy::SubchannelPicker& picker, |
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UnstartedCallHandler& unstarted_handler) { |
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// Perform LB pick.
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auto& client_initial_metadata = |
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unstarted_handler.UnprocessedClientInitialMetadata(); |
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LoadBalancingPolicy::PickArgs pick_args; |
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Slice* path = client_initial_metadata.get_pointer(HttpPathMetadata()); |
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CHECK(path != nullptr); |
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pick_args.path = path->as_string_view(); |
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LbCallState lb_call_state; |
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pick_args.call_state = &lb_call_state; |
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LbMetadata initial_metadata(&client_initial_metadata); |
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pick_args.initial_metadata = &initial_metadata; |
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auto result = picker.Pick(pick_args); |
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// Handle result.
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return HandlePickResult< |
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LoopCtl<absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>>>( |
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&result, |
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// CompletePick
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[&](LoadBalancingPolicy::PickResult::Complete* complete_pick) |
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-> LoopCtl<absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>> { |
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if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_lb_call_trace)) { |
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gpr_log(GPR_INFO, |
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"client_channel: %sLB pick succeeded: subchannel=%p", |
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GetContext<Activity>()->DebugTag().c_str(), |
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complete_pick->subchannel.get()); |
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} |
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CHECK(complete_pick->subchannel != nullptr); |
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// Grab a ref to the call destination while we're still
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// holding the data plane mutex.
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auto call_destination = |
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DownCast<SubchannelInterfaceWithCallDestination*>( |
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complete_pick->subchannel.get()) |
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->call_destination(); |
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// If the subchannel has no call destination (e.g., if the
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// subchannel has moved out of state READY but the LB policy hasn't
|
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// yet seen that change and given us a new picker), then just
|
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// queue the pick. We'll try again as soon as we get a new picker.
|
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if (call_destination == nullptr) { |
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if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_lb_call_trace)) { |
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gpr_log(GPR_INFO, |
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"client_channel: %ssubchannel returned by LB picker " |
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"has no connected subchannel; queueing pick", |
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GetContext<Activity>()->DebugTag().c_str()); |
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} |
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return Continue{}; |
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} |
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// If the LB policy returned a call tracker, inform it that the
|
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// call is starting and add it to context, so that we can notify
|
||||
// it when the call finishes.
|
||||
if (complete_pick->subchannel_call_tracker != nullptr) { |
||||
complete_pick->subchannel_call_tracker->Start(); |
||||
SetContext(complete_pick->subchannel_call_tracker.release()); |
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} |
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// Return the connected subchannel.
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return call_destination; |
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}, |
||||
// QueuePick
|
||||
[&](LoadBalancingPolicy::PickResult::Queue* /*queue_pick*/) { |
||||
if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_lb_call_trace)) { |
||||
gpr_log(GPR_INFO, "client_channel: %sLB pick queued", |
||||
GetContext<Activity>()->DebugTag().c_str()); |
||||
} |
||||
return Continue{}; |
||||
}, |
||||
// FailPick
|
||||
[&](LoadBalancingPolicy::PickResult::Fail* fail_pick) |
||||
-> LoopCtl<absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>> { |
||||
if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_lb_call_trace)) { |
||||
gpr_log(GPR_INFO, "client_channel: %sLB pick failed: %s", |
||||
GetContext<Activity>()->DebugTag().c_str(), |
||||
fail_pick->status.ToString().c_str()); |
||||
} |
||||
// If wait_for_ready is false, then the error indicates the RPC
|
||||
// attempt's final status.
|
||||
if (!unstarted_handler.UnprocessedClientInitialMetadata() |
||||
.GetOrCreatePointer(WaitForReady()) |
||||
->value) { |
||||
return MaybeRewriteIllegalStatusCode(std::move(fail_pick->status), |
||||
"LB pick"); |
||||
} |
||||
// If wait_for_ready is true, then queue to retry when we get a new
|
||||
// picker.
|
||||
return Continue{}; |
||||
}, |
||||
// DropPick
|
||||
[&](LoadBalancingPolicy::PickResult::Drop* drop_pick) |
||||
-> LoopCtl<absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>> { |
||||
if (GRPC_TRACE_FLAG_ENABLED(grpc_client_channel_lb_call_trace)) { |
||||
gpr_log(GPR_INFO, "client_channel: %sLB pick dropped: %s", |
||||
GetContext<Activity>()->DebugTag().c_str(), |
||||
drop_pick->status.ToString().c_str()); |
||||
} |
||||
return grpc_error_set_int(MaybeRewriteIllegalStatusCode( |
||||
std::move(drop_pick->status), "LB drop"), |
||||
StatusIntProperty::kLbPolicyDrop, 1); |
||||
}); |
||||
} |
||||
|
||||
} // namespace
|
||||
|
||||
void LoadBalancedCallDestination::StartCall( |
||||
UnstartedCallHandler unstarted_handler) { |
||||
// If there is a call tracer, create a call attempt tracer.
|
||||
bool* is_transparent_retry_metadata = |
||||
unstarted_handler.UnprocessedClientInitialMetadata().get_pointer( |
||||
IsTransparentRetry()); |
||||
bool is_transparent_retry = is_transparent_retry_metadata != nullptr |
||||
? *is_transparent_retry_metadata |
||||
: false; |
||||
MaybeCreateCallAttemptTracer(is_transparent_retry); |
||||
// Spawn a promise to do the LB pick.
|
||||
// This will eventually start the call.
|
||||
unstarted_handler.SpawnGuardedUntilCallCompletes( |
||||
"lb_pick", [unstarted_handler, picker = picker_]() mutable { |
||||
return Map( |
||||
// Wait for the LB picker.
|
||||
CheckDelayed(Loop( |
||||
[last_picker = |
||||
RefCountedPtr<LoadBalancingPolicy::SubchannelPicker>(), |
||||
unstarted_handler, picker]() mutable { |
||||
return Map( |
||||
picker.Next(last_picker), |
||||
[unstarted_handler, &last_picker]( |
||||
RefCountedPtr<LoadBalancingPolicy::SubchannelPicker> |
||||
picker) mutable { |
||||
last_picker = std::move(picker); |
||||
// Returns 3 possible things:
|
||||
// - Continue to queue the pick
|
||||
// - non-OK status to fail the pick
|
||||
// - a connected subchannel to complete the pick
|
||||
return PickSubchannel(*last_picker, unstarted_handler); |
||||
}); |
||||
})), |
||||
// Create call stack on the connected subchannel.
|
||||
[unstarted_handler]( |
||||
std::tuple< |
||||
absl::StatusOr<RefCountedPtr<UnstartedCallDestination>>, |
||||
bool> |
||||
pick_result) { |
||||
auto& call_destination = std::get<0>(pick_result); |
||||
const bool was_queued = std::get<1>(pick_result); |
||||
if (!call_destination.ok()) { |
||||
return call_destination.status(); |
||||
} |
||||
// LB pick is done, so indicate that we've committed.
|
||||
auto* on_commit = MaybeGetContext<LbOnCommit>(); |
||||
if (on_commit != nullptr && *on_commit != nullptr) { |
||||
(*on_commit)(); |
||||
} |
||||
// If it was queued, add a trace annotation.
|
||||
if (was_queued) { |
||||
auto* tracer = |
||||
MaybeGetContext<ClientCallTracer::CallAttemptTracer>(); |
||||
if (tracer != nullptr) { |
||||
tracer->RecordAnnotation("Delayed LB pick complete."); |
||||
} |
||||
} |
||||
// Delegate to connected subchannel.
|
||||
// TODO(ctiller): need to insert LbCallTracingFilter at the top of
|
||||
// the stack
|
||||
(*call_destination)->StartCall(unstarted_handler); |
||||
return absl::OkStatus(); |
||||
}); |
||||
}); |
||||
} |
||||
|
||||
} // namespace grpc_core
|
||||
@ -0,0 +1,49 @@ |
||||
// Copyright 2024 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_SRC_CORE_CLIENT_CHANNEL_LOAD_BALANCED_CALL_DESTINATION_H |
||||
#define GRPC_SRC_CORE_CLIENT_CHANNEL_LOAD_BALANCED_CALL_DESTINATION_H |
||||
|
||||
#include "absl/functional/any_invocable.h" |
||||
|
||||
#include "src/core/client_channel/client_channel.h" |
||||
#include "src/core/lib/promise/context.h" |
||||
#include "src/core/lib/transport/call_destination.h" |
||||
#include "src/core/load_balancing/lb_policy.h" |
||||
|
||||
namespace grpc_core { |
||||
|
||||
// Context type for LB on_commit callback.
|
||||
// TODO(ctiller): make this a struct, so we don't accidentally alias context
|
||||
// types
|
||||
using LbOnCommit = absl::AnyInvocable<void()>; |
||||
template <> |
||||
struct ContextType<LbOnCommit> {}; |
||||
|
||||
class LoadBalancedCallDestination final : public UnstartedCallDestination { |
||||
public: |
||||
explicit LoadBalancedCallDestination(ClientChannel::PickerObservable picker) |
||||
: picker_(std::move(picker)) {} |
||||
|
||||
void Orphaned() override {} |
||||
|
||||
void StartCall(UnstartedCallHandler unstarted_handler) override; |
||||
|
||||
private: |
||||
ClientChannel::PickerObservable picker_; |
||||
}; |
||||
|
||||
} // namespace grpc_core
|
||||
|
||||
#endif // GRPC_SRC_CORE_CLIENT_CHANNEL_LOAD_BALANCED_CALL_DESTINATION_H
|
||||
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