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/**
* 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
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