foundationdb/fdbclient/MonitorLeader.h

51 lines
2.2 KiB
C++

/*
* MonitorLeader.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2018 Apple Inc. and the FoundationDB project 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 FDBCLIENT_MONITORLEADER_H
#define FDBCLIENT_MONITORLEADER_H
#pragma once
#include "fdbclient/FDBTypes.h"
#include "fdbclient/CoordinationInterface.h"
#define CLUSTER_FILE_ENV_VAR_NAME "FDB_CLUSTER_FILE"
class ClientCoordinators;
template <class LeaderInterface>
Future<Void> monitorLeader( Reference<ClusterConnectionFile> const& connFile, Reference<AsyncVar<Optional<LeaderInterface>>> const& outKnownLeader, Reference<AsyncVar<int>> connectedCoordinatorsNum = Reference<AsyncVar<int>>() );
// Monitors the given coordination group's leader election process and provides a best current guess
// of the current leader. If a leader is elected for long enough and communication with a quorum of
// coordinators is possible, eventually outKnownLeader will be that leader's interface.
#pragma region Implementation
Future<Void> monitorLeaderInternal( Reference<ClusterConnectionFile> const& connFile, Reference<AsyncVar<Value>> const& outSerializedLeaderInfo, Reference<AsyncVar<int>> const& connectedCoordinatorsNum );
template <class LeaderInterface>
Future<Void> monitorLeader( Reference<ClusterConnectionFile> const& connFile, Reference<AsyncVar<Optional<LeaderInterface>>> const& outKnownLeader, Reference<AsyncVar<int>> connectedCoordinatorsNum ) {
Reference<AsyncVar<Value>> serializedInfo( new AsyncVar<Value> );
Future<Void> m = monitorLeaderInternal( connFile, serializedInfo, connectedCoordinatorsNum );
return m || asyncDeserialize( serializedInfo, outKnownLeader );
}
#pragma endregion
#endif