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/**
* Copyright (C) 2020-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/internal_session_pool.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/persistent_task_store.h"
#include "mongo/db/repl/replication_coordinator.h"
#include "mongo/db/repl/wait_for_majority_service.h"
#include "mongo/db/s/dist_lock_manager.h"
#include "mongo/db/s/forwardable_operation_metadata.h"
#include "mongo/db/s/sharding_ddl_coordinator_gen.h"
#include "mongo/db/s/sharding_ddl_coordinator_service.h"
#include "mongo/executor/task_executor.h"
#include "mongo/util/future.h"
namespace mongo {
ShardingDDLCoordinatorMetadata extractShardingDDLCoordinatorMetadata(const BSONObj& coorDoc);
class ShardingDDLCoordinator
: public repl::PrimaryOnlyService::TypedInstance<ShardingDDLCoordinator> {
public:
explicit ShardingDDLCoordinator(ShardingDDLCoordinatorService* service, const BSONObj& coorDoc);
~ShardingDDLCoordinator();
/*
* Check if the given coordinator document has the same options as this.
*
* This is used to decide if we can join a previously created coordinator.
* In the case the given coordinator document has incompatible options with this,
* this function must throw a ConflictingOperationInProgress exception with an adequate message.
*/
virtual void checkIfOptionsConflict(const BSONObj& coorDoc) const = 0;
/*
* Returns a future that will be completed when the construction of this coordinator instance
* is completed.
*
* In particular the returned future will be ready only after this coordinator succesfully
* aquires the required locks.
*/
SharedSemiFuture<void> getConstructionCompletionFuture() {
return _constructionCompletionPromise.getFuture();
}
/*
* Returns a future that will be ready when all the work associated with this coordinator
* isntances will be completed.
*
* In particular the returned future will be ready after this coordinator will succesfully
* release all the aquired locks.
*/
SharedSemiFuture<void> getCompletionFuture() {
return _completionPromise.getFuture();
}
const NamespaceString& nss() const {
return _coordId.getNss();
}
DDLCoordinatorTypeEnum operationType() const {
return _coordId.getOperationType();
}
const ForwardableOperationMetadata& getForwardableOpMetadata() const {
invariant(metadata().getForwardableOpMetadata());
return metadata().getForwardableOpMetadata().get();
}
const boost::optional<mongo::DatabaseVersion>& getDatabaseVersion() const& {
return metadata().getDatabaseVersion();
}
protected:
virtual std::vector<StringData> _acquireAdditionalLocks(OperationContext* opCtx) {
return {};
};
virtual ShardingDDLCoordinatorMetadata const& metadata() const = 0;
template <typename StateDoc>
StateDoc _insertStateDocument(StateDoc&& newDoc) {
auto copyMetadata = newDoc.getShardingDDLCoordinatorMetadata();
copyMetadata.setRecoveredFromDisk(true);
newDoc.setShardingDDLCoordinatorMetadata(copyMetadata);
auto opCtx = cc().makeOperationContext();
PersistentTaskStore<StateDoc> store(NamespaceString::kShardingDDLCoordinatorsNamespace);
try {
store.add(opCtx.get(), newDoc, WriteConcerns::kMajorityWriteConcernNoTimeout);
} catch (const ExceptionFor<ErrorCodes::DuplicateKey>&) {
// A series of step-up and step-down events can cause a node to try and insert the
// document when it has already been persisted locally, but we must still wait for
// majority commit.
const auto replCoord = repl::ReplicationCoordinator::get(opCtx.get());
const auto lastLocalOpTime = replCoord->getMyLastAppliedOpTime();
WaitForMajorityService::get(opCtx->getServiceContext())
.waitUntilMajority(lastLocalOpTime, opCtx.get()->getCancellationToken())
.get(opCtx.get());
}
return std::move(newDoc);
}
template <typename StateDoc>
StateDoc _updateStateDocument(OperationContext* opCtx, StateDoc&& newDoc) {
PersistentTaskStore<StateDoc> store(NamespaceString::kShardingDDLCoordinatorsNamespace);
invariant(newDoc.getShardingDDLCoordinatorMetadata().getRecoveredFromDisk());
store.update(opCtx,
BSON(StateDoc::kIdFieldName << newDoc.getId().toBSON()),
newDoc.toBSON(),
WriteConcerns::kMajorityWriteConcernNoTimeout);
return std::move(newDoc);
}
// lazily acqiure Logical Session ID and a txn number
template <typename StateDoc>
StateDoc _updateSession(OperationContext* opCtx, StateDoc const& doc) {
auto newShardingDDLCoordinatorMetadata = doc.getShardingDDLCoordinatorMetadata();
auto optSession = newShardingDDLCoordinatorMetadata.getSession();
if (optSession) {
auto txnNumber = optSession->getTxnNumber();
optSession->setTxnNumber(++txnNumber);
newShardingDDLCoordinatorMetadata.setSession(optSession);
} else {
auto session = InternalSessionPool::get(opCtx)->acquire(opCtx);
newShardingDDLCoordinatorMetadata.setSession(
ShardingDDLSession(session.getSessionId(), session.getTxnNumber()));
}
StateDoc newDoc(doc);
newDoc.setShardingDDLCoordinatorMetadata(std::move(newShardingDDLCoordinatorMetadata));
return _updateStateDocument(opCtx, std::move(newDoc));
}
template <typename StateDoc>
OperationSessionInfo getCurrentSession(StateDoc const& doc) const {
invariant(doc.getShardingDDLCoordinatorMetadata().getSession());
ShardingDDLSession shardingDDLSession =
*doc.getShardingDDLCoordinatorMetadata().getSession();
OperationSessionInfo osi;
osi.setSessionId(shardingDDLSession.getLsid());
osi.setTxnNumber(shardingDDLSession.getTxnNumber());
return osi;
}
/*
* Performs a noop write on all shards and the configsvr using the sessionId and txnNumber
* specified in 'osi'.
*/
void _performNoopRetryableWriteOnAllShardsAndConfigsvr(
OperationContext* opCtx,
const OperationSessionInfo& osi,
const std::shared_ptr<executor::TaskExecutor>& executor);
/*
* Specify if the coordinator must indefinitely be retried in case of exceptions. It is always
* expected for a coordinator to make progress after performing intermediate operations that
* can't be rollbacked.
*/
virtual bool _mustAlwaysMakeProgress() {
return false;
};
ShardingDDLCoordinatorService* _service;
const ShardingDDLCoordinatorId _coordId;
const bool _recoveredFromDisk;
bool _firstExecution{
true}; // True only when executing the coordinator for the first time (meaning it's not a
// retry after a retryable error nor a recovered instance from a previous primary)
bool _completeOnError{false};
private:
SemiFuture<void> run(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept override final;
virtual ExecutorFuture<void> _runImpl(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token) noexcept = 0;
void interrupt(Status status) override final;
bool _removeDocument(OperationContext* opCtx);
ExecutorFuture<bool> _removeDocumentUntillSuccessOrStepdown(
std::shared_ptr<executor::TaskExecutor> executor);
ExecutorFuture<void> _acquireLockAsync(std::shared_ptr<executor::ScopedTaskExecutor> executor,
const CancellationToken& token,
StringData resource);
Mutex _mutex = MONGO_MAKE_LATCH("ShardingDDLCoordinator::_mutex");
SharedPromise<void> _constructionCompletionPromise;
SharedPromise<void> _completionPromise;
std::stack<DistLockManager::ScopedLock> _scopedLocks;
};
} // namespace mongo
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