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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/db/logical_session_cache.h"
#include "mongo/db/logical_session_id.h"
#include "mongo/db/refresh_sessions_gen.h"
#include "mongo/db/service_liaison.h"
#include "mongo/db/sessions_collection.h"
#include "mongo/db/time_proof_service.h"
#include "mongo/db/transaction_reaper.h"
#include "mongo/platform/atomic_word.h"
#include "mongo/stdx/thread.h"
#include "mongo/util/lru_cache.h"
namespace mongo {
class Client;
class OperationContext;
class ServiceContext;
extern int logicalSessionRefreshMillis;
/**
* A thread-safe cache structure for logical session records.
*
* The cache takes ownership of the passed-in ServiceLiaison and
* SessionsCollection helper types.
*/
class LogicalSessionCacheImpl final : public LogicalSessionCache {
public:
static constexpr Milliseconds kLogicalSessionDefaultRefresh = Milliseconds(5 * 60 * 1000);
/**
* An Options type to support the LogicalSessionCacheImpl.
*/
struct Options {
Options(){};
/**
* A timeout value to use for sessions in the cache, in minutes.
*
* By default, this is set to 30 minutes.
*
* May be set with --setParameter localLogicalSessionTimeoutMinutes=X.
*/
Minutes sessionTimeout = Minutes(localLogicalSessionTimeoutMinutes);
/**
* The interval over which the cache will refresh session records.
*
* By default, this is set to every 5 minutes (300,000). If the caller
* is setting the sessionTimeout by hand, it is suggested that they
* consider also setting the refresh interval accordingly.
*
* May be set with --setParameter logicalSessionRefreshMillis=X.
*/
Milliseconds refreshInterval = Milliseconds(logicalSessionRefreshMillis);
};
/**
* Construct a new session cache.
*/
explicit LogicalSessionCacheImpl(std::unique_ptr<ServiceLiaison> service,
std::shared_ptr<SessionsCollection> collection,
std::shared_ptr<TransactionReaper> transactionReaper,
Options options = Options{});
LogicalSessionCacheImpl(const LogicalSessionCacheImpl&) = delete;
LogicalSessionCacheImpl& operator=(const LogicalSessionCacheImpl&) = delete;
~LogicalSessionCacheImpl();
Status promote(LogicalSessionId lsid) override;
Status startSession(OperationContext* opCtx, LogicalSessionRecord record) override;
Status refreshSessions(OperationContext* opCtx,
const RefreshSessionsCmdFromClient& cmd) override;
Status refreshSessions(OperationContext* opCtx,
const RefreshSessionsCmdFromClusterMember& cmd) override;
Status vivify(OperationContext* opCtx, const LogicalSessionId& lsid) override;
Status refreshNow(Client* client) override;
Status reapNow(Client* client) override;
Date_t now() override;
size_t size() override;
std::vector<LogicalSessionId> listIds() const override;
std::vector<LogicalSessionId> listIds(
const std::vector<SHA256Block>& userDigest) const override;
boost::optional<LogicalSessionRecord> peekCached(const LogicalSessionId& id) const override;
void endSessions(const LogicalSessionIdSet& sessions) override;
LogicalSessionCacheStats getStats() override;
private:
/**
* Internal methods to handle scheduling and perform refreshes for active
* session records contained within the cache.
*/
void _periodicRefresh(Client* client);
void _refresh(Client* client);
void _periodicReap(Client* client);
Status _reap(Client* client);
/**
* Returns true if a record has passed its given expiration.
*/
bool _isDead(const LogicalSessionRecord& record, Date_t now) const;
/**
* Takes the lock and inserts the given record into the cache.
*/
Status _addToCache(LogicalSessionRecord record);
const Milliseconds _refreshInterval;
const Minutes _sessionTimeout;
// This value is only modified under the lock, and is modified
// automatically by the background jobs.
LogicalSessionCacheStats _stats;
std::unique_ptr<ServiceLiaison> _service;
std::shared_ptr<SessionsCollection> _sessionsColl;
mutable stdx::mutex _reaperMutex;
std::shared_ptr<TransactionReaper> _transactionReaper;
mutable stdx::mutex _cacheMutex;
LogicalSessionIdMap<LogicalSessionRecord> _activeSessions;
LogicalSessionIdSet _endingSessions;
Date_t lastRefreshTime;
};
} // namespace mongo
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