mirror of https://gitee.com/bigwinds/arangodb
152 lines
4.3 KiB
C++
152 lines
4.3 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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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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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Kaveh Vahedipour
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////////////////////////////////////////////////////////////////////////////////
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#ifndef __ARANGODB_CONSENSUS_AGENT__
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#define __ARANGODB_CONSENSUS_AGENT__
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#include "AgencyCommon.h"
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#include "AgentCallback.h"
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#include "Constituent.h"
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#include "State.h"
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#include "Store.h"
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namespace arangodb {
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namespace consensus {
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class Agent : public arangodb::Thread {
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public:
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/// @brief Default ctor
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Agent();
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/// @brief Construct with program options
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explicit Agent(config_t const&);
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/// @brief Clean up
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virtual ~Agent();
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/// @brief Get current term
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term_t term() const;
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/// @brief Get current term
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id_t id() const;
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/// @brief Vote request
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priv_rpc_ret_t requestVote(term_t, id_t, index_t, index_t, query_t const&);
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/// @brief Provide configuration
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config_t const& config() const;
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/// @brief Start thread
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bool start();
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/// @brief Verbose print of myself
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////
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void print(arangodb::LoggerStream&) const;
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/// @brief Are we fit to run?
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bool fitness() const;
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/// @brief Leader ID
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id_t leaderID() const;
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bool leading() const;
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/// @brief Pick up leadership tasks
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bool lead();
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/// @brief Load persistent state
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bool load();
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/// @brief Attempt write
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write_ret_t write(query_t const&);
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/// @brief Read from agency
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read_ret_t read(query_t const&) const;
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/// @brief Received by followers to replicate log entries (§5.3);
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/// also used as heartbeat (§5.2).
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bool recvAppendEntriesRPC(term_t term, id_t leaderId, index_t prevIndex,
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term_t prevTerm, index_t lastCommitIndex,
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query_t const& queries);
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/// @brief Invoked by leader to replicate log entries (§5.3);
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/// also used as heartbeat (§5.2).
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append_entries_t sendAppendEntriesRPC(id_t slave_id);
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/// @brief 1. Deal with appendEntries to slaves.
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/// 2. Report success of write processes.
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void run() override final;
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/// @brief Start orderly shutdown of threads
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void beginShutdown() override final;
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/// @brief Report appended entries from AgentCallback
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void reportIn(id_t id, index_t idx);
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/// @brief Wait for slaves to confirm appended entries
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bool waitFor(index_t last_entry, duration_t timeout = duration_t(2000));
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/// @brief Convencience size of agency
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size_t size() const;
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/// @brief Rebuild DBs by applying state log to empty DB
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bool rebuildDBs();
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/// @brief Last log entry
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log_t const& lastLog() const;
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/// @brief Pipe configuration to ostream
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friend std::ostream& operator<<(std::ostream& o, Agent const& a) {
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o << a.config();
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return o;
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}
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/// @brief Persist term
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void persist (term_t, id_t);
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/// @brief State machine
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State const& state() const;
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private:
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Constituent _constituent; /**< @brief Leader election delegate */
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State _state; /**< @brief Log replica */
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config_t _config; /**< @brief Command line arguments */
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std::atomic<index_t> _last_commit_index; /**< @brief Last commit index */
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arangodb::Mutex _uncommitedLock; /**< @brief */
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Store _spearhead; /**< @brief Spearhead key value store */
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Store _read_db; /**< @brief Read key value store */
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arangodb::basics::ConditionVariable _cv; /**< @brief Internal callbacks */
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arangodb::basics::ConditionVariable _rest_cv; /**< @brief Rest handler */
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std::vector<index_t>
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_confirmed; /**< @brief Confirmed log index of each slave */
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arangodb::Mutex _ioLock; /**< @brief Read/Write lock */
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};
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}
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}
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#endif
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