| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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 __LOG_COORDINATOR_HPP__ |
| #define __LOG_COORDINATOR_HPP__ |
| |
| #include <stdint.h> |
| |
| #include <string> |
| |
| #include <process/future.hpp> |
| #include <process/shared.hpp> |
| |
| #include <stout/option.hpp> |
| |
| #include "log/network.hpp" |
| #include "log/replica.hpp" |
| |
| namespace mesos { |
| namespace internal { |
| namespace log { |
| |
| // Forward declaration. |
| class CoordinatorProcess; |
| |
| |
| class Coordinator |
| { |
| public: |
| Coordinator( |
| size_t _quorum, |
| const process::Shared<Replica>& _replica, |
| const process::Shared<Network>& _network); |
| |
| ~Coordinator(); |
| |
| // Handles coordinator election. Returns the last committed (a.k.a., |
| // learned) log position if the operation succeeds. Returns none if |
| // the election is not successful, but can be retried. |
| process::Future<Option<uint64_t> > elect(); |
| |
| // Handles coordinator demotion. Returns the last committed (a.k.a., |
| // learned) log position if the operation succeeds. One should only |
| // call this function if the coordinator has been elected, and no |
| // write (append or truncate) is in progress. |
| process::Future<uint64_t> demote(); |
| |
| // Appends the specified bytes to the end of the log. Returns the |
| // position of the appended entry if the operation succeeds or none |
| // if the coordinator was demoted. |
| process::Future<Option<uint64_t> > append(const std::string& bytes); |
| |
| // Removes all log entries preceding the log entry at the given |
| // position (to). Returns the position at which the truncate |
| // operation is written if the operation succeeds or none if the |
| // coordinator was demoted. |
| process::Future<Option<uint64_t> > truncate(uint64_t to); |
| |
| private: |
| CoordinatorProcess* process; |
| }; |
| |
| } // namespace log { |
| } // namespace internal { |
| } // namespace mesos { |
| |
| #endif // __LOG_COORDINATOR_HPP__ |