mirror of https://github.com/grpc/grpc.git
Merge pull request #18917 from markdroth/subchannel_interface
Use SubchannelInterface to hide implementation from LB policy APIpull/19197/head
Mark D. Roth
6 years ago
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GitHub
commit
d26201494b
22 changed files with 302 additions and 157 deletions
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/*
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* |
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* Copyright 2019 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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*/ |
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#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H |
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#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H |
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#include <grpc/support/port_platform.h> |
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#include "src/core/lib/debug/trace.h" |
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#include "src/core/lib/gprpp/ref_counted.h" |
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#include "src/core/lib/gprpp/ref_counted_ptr.h" |
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namespace grpc_core { |
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// TODO(roth): In a subsequent PR, remove this from this API.
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class ConnectedSubchannelInterface |
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: public RefCounted<ConnectedSubchannelInterface> { |
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public: |
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virtual const grpc_channel_args* args() const GRPC_ABSTRACT; |
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protected: |
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template <typename TraceFlagT = TraceFlag> |
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explicit ConnectedSubchannelInterface(TraceFlagT* trace_flag = nullptr) |
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: RefCounted<ConnectedSubchannelInterface>(trace_flag) {} |
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}; |
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class SubchannelInterface : public RefCounted<SubchannelInterface> { |
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public: |
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class ConnectivityStateWatcher { |
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public: |
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virtual ~ConnectivityStateWatcher() = default; |
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// Will be invoked whenever the subchannel's connectivity state
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// changes. There will be only one invocation of this method on a
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// given watcher instance at any given time.
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//
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// When the state changes to READY, connected_subchannel will
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// contain a ref to the connected subchannel. When it changes from
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// READY to some other state, the implementation must release its
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// ref to the connected subchannel.
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virtual void OnConnectivityStateChange( |
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grpc_connectivity_state new_state, |
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RefCountedPtr<ConnectedSubchannelInterface> |
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connected_subchannel) // NOLINT
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GRPC_ABSTRACT; |
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// TODO(roth): Remove this as soon as we move to EventManager-based
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// polling.
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virtual grpc_pollset_set* interested_parties() GRPC_ABSTRACT; |
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GRPC_ABSTRACT_BASE_CLASS |
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}; |
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virtual ~SubchannelInterface() = default; |
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// Returns the current connectivity state of the subchannel.
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virtual grpc_connectivity_state CheckConnectivityState( |
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RefCountedPtr<ConnectedSubchannelInterface>* connected_subchannel) |
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GRPC_ABSTRACT; |
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// Starts watching the subchannel's connectivity state.
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// The first callback to the watcher will be delivered when the
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// subchannel's connectivity state becomes a value other than
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// initial_state, which may happen immediately.
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// Subsequent callbacks will be delivered as the subchannel's state
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// changes.
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// The watcher will be destroyed either when the subchannel is
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// destroyed or when CancelConnectivityStateWatch() is called.
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// There can be only one watcher of a given subchannel. It is not
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// valid to call this method a second time without first cancelling
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// the previous watcher using CancelConnectivityStateWatch().
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virtual void WatchConnectivityState( |
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grpc_connectivity_state initial_state, |
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UniquePtr<ConnectivityStateWatcher> watcher) GRPC_ABSTRACT; |
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// Cancels a connectivity state watch.
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// If the watcher has already been destroyed, this is a no-op.
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virtual void CancelConnectivityStateWatch(ConnectivityStateWatcher* watcher) |
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GRPC_ABSTRACT; |
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// Attempt to connect to the backend. Has no effect if already connected.
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virtual void AttemptToConnect() GRPC_ABSTRACT; |
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// TODO(roth): These methods should be removed from this interface to
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// bettter hide grpc-specific functionality from the LB policy API.
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virtual channelz::SubchannelNode* channelz_node() GRPC_ABSTRACT; |
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virtual void ResetBackoff() GRPC_ABSTRACT; |
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GRPC_ABSTRACT_BASE_CLASS |
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}; |
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} // namespace grpc_core
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#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_SUBCHANNEL_INTERFACE_H */ |
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