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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 <list>
#include <string>
#include <vector>
#include "mongo/base/status.h"
#include "mongo/base/status_with.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/client/fetcher.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/repl/base_cloner.h"
#include "mongo/db/repl/collection_cloner.h"
#include "mongo/db/repl/database_cloner.h"
#include "mongo/executor/task_executor.h"
#include "mongo/platform/condition_variable.h"
#include "mongo/platform/mutex.h"
#include "mongo/util/concurrency/thread_pool.h"
#include "mongo/util/net/hostandport.h"
namespace mongo {
namespace repl {
/**
* Clones all databases.
*/
class DatabasesCloner {
public:
struct Stats {
size_t databasesCloned{0};
std::vector<DatabaseCloner::Stats> databaseStats;
std::string toString() const;
BSONObj toBSON() const;
void append(BSONObjBuilder* builder) const;
};
using IncludeDbFilterFn = std::function<bool(const BSONObj& dbInfo)>;
using OnFinishFn = std::function<void(const Status&)>;
using StartCollectionClonerFn = DatabaseCloner::StartCollectionClonerFn;
using ScheduleDbWorkFn = std::function<StatusWith<executor::TaskExecutor::CallbackHandle>(
executor::TaskExecutor::CallbackFn)>;
DatabasesCloner(StorageInterface* si,
executor::TaskExecutor* exec,
ThreadPool* dbWorkThreadPool,
HostAndPort source,
IncludeDbFilterFn includeDbPred,
OnFinishFn finishFn);
~DatabasesCloner();
Status startup() noexcept;
bool isActive();
void join();
void shutdown();
DatabasesCloner::Stats getStats() const;
/**
* Returns the status after completion. If multiple error occur, only one is recorded/returned.
*
* NOTE: A value of ErrorCodes::NotYetInitialized is the default until started.
*/
Status getStatus();
std::string toString() const;
/**
* Overrides how executor schedules database work.
*
* For testing only.
*/
void setScheduleDbWorkFn_forTest(const ScheduleDbWorkFn& scheduleDbWorkFn);
/**
* Overrides how executor starts a collection cloner.
*
* For testing only.
*/
void setStartCollectionClonerFn(const StartCollectionClonerFn& startCollectionCloner);
/**
* Calls DatabasesCloner::_setAdminAsFirst.
* For testing only.
*/
void setAdminAsFirst_forTest(std::vector<BSONElement>& dbsArray);
/**
* Calls DatabasesCloner::_parseListDatabasesResponse.
* For testing only.
*/
StatusWith<std::vector<BSONElement>> parseListDatabasesResponse_forTest(BSONObj dbResponse);
private:
bool _isActive_inlock() const;
/**
* Returns a copy of the database cloners.
*/
std::vector<std::shared_ptr<DatabaseCloner>> _getDatabaseCloners() const;
/**
* Returns scheduler for listDatabases (null if not created).
*/
RemoteCommandRetryScheduler* _getListDatabasesScheduler() const;
/**
* Setting the status to not-OK will stop the process
*/
void _setStatus_inlock(Status s);
/** Will fail the cloner, call the completion function, and become inactive. */
void _fail_inlock(stdx::unique_lock<Latch>* lk, Status s);
/** Will call the completion function, and become inactive. */
void _succeed_inlock(stdx::unique_lock<Latch>* lk);
/** Called each time a database clone is finished */
void _onEachDBCloneFinish(const Status& status, const std::string& name);
// Callbacks
void _onListDatabaseFinish(const executor::TaskExecutor::RemoteCommandCallbackArgs& cbd);
/**
* Takes a vector of BSONElements and scans for an element that contains a 'name' field with the
* value 'admin'. If found, the element is swapped with the first element in the vector.
* Otherwise, return.
*
* Used to parse the BSONResponse returned by listDatabases.
*/
void _setAdminAsFirst(std::vector<BSONElement>& dbsArray);
/**
* Takes a 'listDatabases' command response and parses the response into a
* vector of BSON elements.
*
* If the input response is malformed, Status ErrorCodes::BadValue will be returned.
*/
StatusWith<std::vector<BSONElement>> _parseListDatabasesResponse(BSONObj dbResponse);
//
// All member variables are labeled with one of the following codes indicating the
// synchronization rules for accessing them.
//
// (R) Read-only in concurrent operation; no synchronization required.
// (M) Reads and writes guarded by _mutex
// (S) Self-synchronizing; access in any way from any context.
//
mutable Mutex _mutex = MONGO_MAKE_LATCH("DatabasesCloner::_mutex"); // (S)
Status _status{ErrorCodes::NotYetInitialized, ""}; // (M) If it is not OK, we stop everything.
executor::TaskExecutor* _exec; // (R) executor to schedule things with
ThreadPool* _dbWorkThreadPool; // (R) db worker thread pool for collection cloning.
const HostAndPort _source; // (R) The source to use.
ScheduleDbWorkFn _scheduleDbWorkFn; // (M)
StartCollectionClonerFn _startCollectionClonerFn; // (M)
const IncludeDbFilterFn _includeDbFn; // (R) function which decides which dbs are cloned.
OnFinishFn _finishFn; // (M) function called when finished.
StorageInterface* _storage; // (R)
std::unique_ptr<RemoteCommandRetryScheduler> _listDBsScheduler; // (M) scheduler for listDBs.
std::vector<std::shared_ptr<DatabaseCloner>> _databaseCloners; // (M) database cloners by name
Stats _stats; // (M)
// State transitions:
// PreStart --> Running --> ShuttingDown --> Complete
// It is possible to skip intermediate states. For example,
// Calling shutdown() when the cloner has not started will transition from PreStart directly
// to Complete.
enum class State { kPreStart, kRunning, kShuttingDown, kComplete };
State _state = State::kPreStart;
};
} // namespace repl
} // namespace mongo
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