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Diffstat (limited to 'src/mongo/s/router.h')
-rw-r--r-- | src/mongo/s/router.h | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/mongo/s/router.h b/src/mongo/s/router.h new file mode 100644 index 00000000000..6cfd1d9e546 --- /dev/null +++ b/src/mongo/s/router.h @@ -0,0 +1,125 @@ +/** + * Copyright (C) 2022-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/bson/bsonobjbuilder.h" +#include "mongo/db/namespace_string.h" +#include "mongo/db/operation_context.h" +#include "mongo/s/catalog_cache.h" + +namespace mongo { +namespace sharding { +namespace router { + +class RouterBase { +protected: + RouterBase(ServiceContext* service); + + struct RouteContext { + const std::string comment; + int numAttempts{0}; + }; + + ServiceContext* const _service; +}; + +// Both the router classes below declare the scope in which their 'route' method is executed as a +// router for the relevant database or collection. These classes are the only way to obtain routing +// information for a given entry. + +/** + * This class should mostly be used for routing of DDL operations which need to be coordinated from + * the primary shard of the database. + */ +class DBPrimaryRouter : public RouterBase { +public: + DBPrimaryRouter(ServiceContext* service, StringData db); + + template <typename F> + auto route(OperationContext* opCtx, StringData comment, F&& callbackFn) { + RouteContext context{comment.toString()}; + while (true) { + auto cdb = _getRoutingInfo(opCtx); + try { + return callbackFn(opCtx, cdb); + } catch (const DBException& ex) { + _onException(&context, ex.toStatus()); + } + } + } + + static void appendDDLRoutingTokenToCommand(const DatabaseType& dbt, BSONObjBuilder* builder); + + static void appendCRUDUnshardedRoutingTokenToCommand(const ShardId& shardId, + const DatabaseVersion& dbVersion, + BSONObjBuilder* builder); + +private: + CachedDatabaseInfo _getRoutingInfo(OperationContext* opCtx) const; + void _onException(RouteContext* context, Status s); + + std::string _db; +}; + +/** + * This class should mostly be used for routing CRUD operations which need to have a view of the + * entire routing table for a collection. + */ +class CollectionRouter : public RouterBase { +public: + CollectionRouter(ServiceContext* service, NamespaceString nss); + + template <typename F> + auto route(OperationContext* opCtx, StringData comment, F&& callbackFn) { + RouteContext context{comment.toString()}; + while (true) { + auto cm = _getRoutingInfo(opCtx); + try { + return callbackFn(opCtx, cm); + } catch (const DBException& ex) { + _onException(&context, ex.toStatus()); + } + } + } + + static void appendCRUDRoutingTokenToCommand(const ShardId& shardId, + const ChunkManager& cm, + BSONObjBuilder* builder); + +private: + ChunkManager _getRoutingInfo(OperationContext* opCtx) const; + void _onException(RouteContext* context, Status s); + + NamespaceString _nss; +}; + +} // namespace router +} // namespace sharding +} // namespace mongo |