| /* |
| * |
| * Copyright 2015 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_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H |
| #define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H |
| |
| #include <grpc/support/port_platform.h> |
| |
| #include <string.h> |
| |
| #include <grpc/support/alloc.h> |
| |
| #include "absl/container/inlined_vector.h" |
| |
| #include "src/core/ext/filters/client_channel/lb_policy_registry.h" |
| #include "src/core/ext/filters/client_channel/server_address.h" |
| // TODO(roth): Should not need the include of subchannel.h here, since |
| // that implementation should be hidden from the LB policy API. |
| #include "src/core/ext/filters/client_channel/subchannel.h" |
| #include "src/core/ext/filters/client_channel/subchannel_interface.h" |
| #include "src/core/lib/address_utils/sockaddr_utils.h" |
| #include "src/core/lib/channel/channel_args.h" |
| #include "src/core/lib/debug/trace.h" |
| #include "src/core/lib/gprpp/orphanable.h" |
| #include "src/core/lib/gprpp/ref_counted.h" |
| #include "src/core/lib/gprpp/ref_counted_ptr.h" |
| #include "src/core/lib/iomgr/closure.h" |
| #include "src/core/lib/transport/connectivity_state.h" |
| |
| // Code for maintaining a list of subchannels within an LB policy. |
| // |
| // To use this, callers must create their own subclasses, like so: |
| /* |
| |
| class MySubchannelList; // Forward declaration. |
| |
| class MySubchannelData |
| : public SubchannelData<MySubchannelList, MySubchannelData> { |
| public: |
| void ProcessConnectivityChangeLocked( |
| grpc_connectivity_state connectivity_state) override { |
| // ...code to handle connectivity changes... |
| } |
| }; |
| |
| class MySubchannelList |
| : public SubchannelList<MySubchannelList, MySubchannelData> { |
| }; |
| |
| */ |
| // All methods will be called from within the client_channel work serializer. |
| |
| namespace grpc_core { |
| |
| // Forward declaration. |
| template <typename SubchannelListType, typename SubchannelDataType> |
| class SubchannelList; |
| |
| // Stores data for a particular subchannel in a subchannel list. |
| // Callers must create a subclass that implements the |
| // ProcessConnectivityChangeLocked() method. |
| template <typename SubchannelListType, typename SubchannelDataType> |
| class SubchannelData { |
| public: |
| // Returns a pointer to the subchannel list containing this object. |
| SubchannelListType* subchannel_list() const { |
| return static_cast<SubchannelListType*>(subchannel_list_); |
| } |
| |
| // Returns the index into the subchannel list of this object. |
| size_t Index() const { |
| return static_cast<size_t>(static_cast<const SubchannelDataType*>(this) - |
| subchannel_list_->subchannel(0)); |
| } |
| |
| // Returns a pointer to the subchannel. |
| SubchannelInterface* subchannel() const { return subchannel_.get(); } |
| |
| // Synchronously checks the subchannel's connectivity state. |
| // Must not be called while there is a connectivity notification |
| // pending (i.e., between calling StartConnectivityWatchLocked() and |
| // calling CancelConnectivityWatchLocked()). |
| grpc_connectivity_state CheckConnectivityStateLocked() { |
| GPR_ASSERT(pending_watcher_ == nullptr); |
| connectivity_state_ = subchannel_->CheckConnectivityState(); |
| return connectivity_state_; |
| } |
| |
| // Resets the connection backoff. |
| // TODO(roth): This method should go away when we move the backoff |
| // code out of the subchannel and into the LB policies. |
| void ResetBackoffLocked(); |
| |
| // Starts watching the connectivity state of the subchannel. |
| // ProcessConnectivityChangeLocked() will be called whenever the |
| // connectivity state changes. |
| void StartConnectivityWatchLocked(); |
| |
| // Cancels watching the connectivity state of the subchannel. |
| void CancelConnectivityWatchLocked(const char* reason); |
| |
| // Cancels any pending connectivity watch and unrefs the subchannel. |
| void ShutdownLocked(); |
| |
| protected: |
| SubchannelData( |
| SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list, |
| const ServerAddress& address, |
| RefCountedPtr<SubchannelInterface> subchannel); |
| |
| virtual ~SubchannelData(); |
| |
| // After StartConnectivityWatchLocked() is called, this method will be |
| // invoked whenever the subchannel's connectivity state changes. |
| // To stop watching, use CancelConnectivityWatchLocked(). |
| virtual void ProcessConnectivityChangeLocked( |
| grpc_connectivity_state connectivity_state) = 0; |
| |
| private: |
| // Watcher for subchannel connectivity state. |
| class Watcher |
| : public SubchannelInterface::ConnectivityStateWatcherInterface { |
| public: |
| Watcher( |
| SubchannelData<SubchannelListType, SubchannelDataType>* subchannel_data, |
| RefCountedPtr<SubchannelListType> subchannel_list) |
| : subchannel_data_(subchannel_data), |
| subchannel_list_(std::move(subchannel_list)) {} |
| |
| ~Watcher() override { |
| subchannel_list_.reset(DEBUG_LOCATION, "Watcher dtor"); |
| } |
| |
| void OnConnectivityStateChange(grpc_connectivity_state new_state) override; |
| |
| grpc_pollset_set* interested_parties() override { |
| return subchannel_list_->policy()->interested_parties(); |
| } |
| |
| private: |
| SubchannelData<SubchannelListType, SubchannelDataType>* subchannel_data_; |
| RefCountedPtr<SubchannelListType> subchannel_list_; |
| }; |
| |
| // Unrefs the subchannel. |
| void UnrefSubchannelLocked(const char* reason); |
| |
| // Backpointer to owning subchannel list. Not owned. |
| SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list_; |
| // The subchannel. |
| RefCountedPtr<SubchannelInterface> subchannel_; |
| // Will be non-null when the subchannel's state is being watched. |
| SubchannelInterface::ConnectivityStateWatcherInterface* pending_watcher_ = |
| nullptr; |
| // Data updated by the watcher. |
| grpc_connectivity_state connectivity_state_; |
| }; |
| |
| // A list of subchannels. |
| template <typename SubchannelListType, typename SubchannelDataType> |
| class SubchannelList : public InternallyRefCounted<SubchannelListType> { |
| public: |
| typedef absl::InlinedVector<SubchannelDataType, 10> SubchannelVector; |
| |
| // The number of subchannels in the list. |
| size_t num_subchannels() const { return subchannels_.size(); } |
| |
| // The data for the subchannel at a particular index. |
| SubchannelDataType* subchannel(size_t index) { return &subchannels_[index]; } |
| |
| // Returns true if the subchannel list is shutting down. |
| bool shutting_down() const { return shutting_down_; } |
| |
| // Accessors. |
| LoadBalancingPolicy* policy() const { return policy_; } |
| TraceFlag* tracer() const { return tracer_; } |
| |
| // Resets connection backoff of all subchannels. |
| // TODO(roth): We will probably need to rethink this as part of moving |
| // the backoff code out of subchannels and into LB policies. |
| void ResetBackoffLocked(); |
| |
| void Orphan() override { |
| ShutdownLocked(); |
| InternallyRefCounted<SubchannelListType>::Unref(DEBUG_LOCATION, "shutdown"); |
| } |
| |
| protected: |
| SubchannelList(LoadBalancingPolicy* policy, TraceFlag* tracer, |
| ServerAddressList addresses, |
| LoadBalancingPolicy::ChannelControlHelper* helper, |
| const grpc_channel_args& args); |
| |
| virtual ~SubchannelList(); |
| |
| private: |
| // For accessing Ref() and Unref(). |
| friend class SubchannelData<SubchannelListType, SubchannelDataType>; |
| |
| void ShutdownLocked(); |
| |
| // Backpointer to owning policy. |
| LoadBalancingPolicy* policy_; |
| |
| TraceFlag* tracer_; |
| |
| // The list of subchannels. |
| SubchannelVector subchannels_; |
| |
| // Is this list shutting down? This may be true due to the shutdown of the |
| // policy itself or because a newer update has arrived while this one hadn't |
| // finished processing. |
| bool shutting_down_ = false; |
| }; |
| |
| // |
| // implementation -- no user-servicable parts below |
| // |
| |
| // |
| // SubchannelData::Watcher |
| // |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, SubchannelDataType>::Watcher:: |
| OnConnectivityStateChange(grpc_connectivity_state new_state) { |
| if (GRPC_TRACE_FLAG_ENABLED(*subchannel_list_->tracer())) { |
| gpr_log(GPR_INFO, |
| "[%s %p] subchannel list %p index %" PRIuPTR " of %" PRIuPTR |
| " (subchannel %p): connectivity changed: state=%s, " |
| "shutting_down=%d, pending_watcher=%p", |
| subchannel_list_->tracer()->name(), subchannel_list_->policy(), |
| subchannel_list_.get(), subchannel_data_->Index(), |
| subchannel_list_->num_subchannels(), |
| subchannel_data_->subchannel_.get(), |
| ConnectivityStateName(new_state), subchannel_list_->shutting_down(), |
| subchannel_data_->pending_watcher_); |
| } |
| if (!subchannel_list_->shutting_down() && |
| subchannel_data_->pending_watcher_ != nullptr) { |
| subchannel_data_->connectivity_state_ = new_state; |
| // Call the subclass's ProcessConnectivityChangeLocked() method. |
| subchannel_data_->ProcessConnectivityChangeLocked(new_state); |
| } |
| } |
| |
| // |
| // SubchannelData |
| // |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| SubchannelData<SubchannelListType, SubchannelDataType>::SubchannelData( |
| SubchannelList<SubchannelListType, SubchannelDataType>* subchannel_list, |
| const ServerAddress& /*address*/, |
| RefCountedPtr<SubchannelInterface> subchannel) |
| : subchannel_list_(subchannel_list), |
| subchannel_(std::move(subchannel)), |
| // We assume that the current state is IDLE. If not, we'll get a |
| // callback telling us that. |
| connectivity_state_(GRPC_CHANNEL_IDLE) {} |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| SubchannelData<SubchannelListType, SubchannelDataType>::~SubchannelData() { |
| GPR_ASSERT(subchannel_ == nullptr); |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, SubchannelDataType>:: |
| UnrefSubchannelLocked(const char* reason) { |
| if (subchannel_ != nullptr) { |
| if (GRPC_TRACE_FLAG_ENABLED(*subchannel_list_->tracer())) { |
| gpr_log(GPR_INFO, |
| "[%s %p] subchannel list %p index %" PRIuPTR " of %" PRIuPTR |
| " (subchannel %p): unreffing subchannel (%s)", |
| subchannel_list_->tracer()->name(), subchannel_list_->policy(), |
| subchannel_list_, Index(), subchannel_list_->num_subchannels(), |
| subchannel_.get(), reason); |
| } |
| subchannel_.reset(); |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, |
| SubchannelDataType>::ResetBackoffLocked() { |
| if (subchannel_ != nullptr) { |
| subchannel_->ResetBackoff(); |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, |
| SubchannelDataType>::StartConnectivityWatchLocked() { |
| if (GRPC_TRACE_FLAG_ENABLED(*subchannel_list_->tracer())) { |
| gpr_log(GPR_INFO, |
| "[%s %p] subchannel list %p index %" PRIuPTR " of %" PRIuPTR |
| " (subchannel %p): starting watch (from %s)", |
| subchannel_list_->tracer()->name(), subchannel_list_->policy(), |
| subchannel_list_, Index(), subchannel_list_->num_subchannels(), |
| subchannel_.get(), ConnectivityStateName(connectivity_state_)); |
| } |
| GPR_ASSERT(pending_watcher_ == nullptr); |
| pending_watcher_ = |
| new Watcher(this, subchannel_list()->Ref(DEBUG_LOCATION, "Watcher")); |
| subchannel_->WatchConnectivityState( |
| connectivity_state_, |
| std::unique_ptr<SubchannelInterface::ConnectivityStateWatcherInterface>( |
| pending_watcher_)); |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, SubchannelDataType>:: |
| CancelConnectivityWatchLocked(const char* reason) { |
| if (GRPC_TRACE_FLAG_ENABLED(*subchannel_list_->tracer())) { |
| gpr_log(GPR_INFO, |
| "[%s %p] subchannel list %p index %" PRIuPTR " of %" PRIuPTR |
| " (subchannel %p): canceling connectivity watch (%s)", |
| subchannel_list_->tracer()->name(), subchannel_list_->policy(), |
| subchannel_list_, Index(), subchannel_list_->num_subchannels(), |
| subchannel_.get(), reason); |
| } |
| if (pending_watcher_ != nullptr) { |
| subchannel_->CancelConnectivityStateWatch(pending_watcher_); |
| pending_watcher_ = nullptr; |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelData<SubchannelListType, SubchannelDataType>::ShutdownLocked() { |
| if (pending_watcher_ != nullptr) CancelConnectivityWatchLocked("shutdown"); |
| UnrefSubchannelLocked("shutdown"); |
| } |
| |
| // |
| // SubchannelList |
| // |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList( |
| LoadBalancingPolicy* policy, TraceFlag* tracer, ServerAddressList addresses, |
| LoadBalancingPolicy::ChannelControlHelper* helper, |
| const grpc_channel_args& args) |
| : InternallyRefCounted<SubchannelListType>( |
| GRPC_TRACE_FLAG_ENABLED(*tracer) ? "SubchannelList" : nullptr), |
| policy_(policy), |
| tracer_(tracer) { |
| if (GRPC_TRACE_FLAG_ENABLED(*tracer_)) { |
| gpr_log(GPR_INFO, |
| "[%s %p] Creating subchannel list %p for %" PRIuPTR " subchannels", |
| tracer_->name(), policy, this, addresses.size()); |
| } |
| subchannels_.reserve(addresses.size()); |
| // Create a subchannel for each address. |
| for (ServerAddress address : addresses) { |
| RefCountedPtr<SubchannelInterface> subchannel = |
| helper->CreateSubchannel(address, args); |
| if (subchannel == nullptr) { |
| // Subchannel could not be created. |
| if (GRPC_TRACE_FLAG_ENABLED(*tracer_)) { |
| gpr_log(GPR_INFO, |
| "[%s %p] could not create subchannel for address %s, " |
| "ignoring", |
| tracer_->name(), policy_, address.ToString().c_str()); |
| } |
| continue; |
| } |
| if (GRPC_TRACE_FLAG_ENABLED(*tracer_)) { |
| gpr_log(GPR_INFO, |
| "[%s %p] subchannel list %p index %" PRIuPTR |
| ": Created subchannel %p for address %s", |
| tracer_->name(), policy_, this, subchannels_.size(), |
| subchannel.get(), address.ToString().c_str()); |
| } |
| subchannels_.emplace_back(this, std::move(address), std::move(subchannel)); |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| SubchannelList<SubchannelListType, SubchannelDataType>::~SubchannelList() { |
| if (GRPC_TRACE_FLAG_ENABLED(*tracer_)) { |
| gpr_log(GPR_INFO, "[%s %p] Destroying subchannel_list %p", tracer_->name(), |
| policy_, this); |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelList<SubchannelListType, SubchannelDataType>::ShutdownLocked() { |
| if (GRPC_TRACE_FLAG_ENABLED(*tracer_)) { |
| gpr_log(GPR_INFO, "[%s %p] Shutting down subchannel_list %p", |
| tracer_->name(), policy_, this); |
| } |
| GPR_ASSERT(!shutting_down_); |
| shutting_down_ = true; |
| for (size_t i = 0; i < subchannels_.size(); i++) { |
| SubchannelDataType* sd = &subchannels_[i]; |
| sd->ShutdownLocked(); |
| } |
| } |
| |
| template <typename SubchannelListType, typename SubchannelDataType> |
| void SubchannelList<SubchannelListType, |
| SubchannelDataType>::ResetBackoffLocked() { |
| for (size_t i = 0; i < subchannels_.size(); i++) { |
| SubchannelDataType* sd = &subchannels_[i]; |
| sd->ResetBackoffLocked(); |
| } |
| } |
| |
| } // namespace grpc_core |
| |
| #endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_LB_POLICY_SUBCHANNEL_LIST_H */ |