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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* 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
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* 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 GNU Affero General 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 <boost/optional.hpp>
#include <memory>
#include <mutex>
#include <string>
#include <vector>
#include "mongo/s/client/shard.h"
namespace mongo {
class BSONObjBuilder;
class CatalogManager;
struct HostAndPort;
class NamespaceString;
class RemoteCommandRunner;
class RemoteCommandTargeterFactory;
class Shard;
class ShardType;
template <typename T>
class StatusWith;
namespace executor {
class TaskExecutor;
} // namespace executor
/**
* Maintains the set of all shards known to the instance and their connections. Manages polling
* the respective replica sets for membership changes.
*/
class ShardRegistry {
public:
/**
* Instantiates a new shard registry.
*
* @param targeterFactory Produces targeters for each shard's individual connection string
* @param commandRunner Command runner for executing commands against hosts
* @param executor Asynchronous task executor to use for making calls to shards.
* @param catalogManager Used to retrieve the list of registered shard. TODO: remove.
*/
ShardRegistry(std::unique_ptr<RemoteCommandTargeterFactory> targeterFactory,
std::unique_ptr<RemoteCommandRunner> commandRunner,
std::unique_ptr<executor::TaskExecutor> executor,
CatalogManager* catalogManager);
~ShardRegistry();
RemoteCommandRunner* getCommandRunner() const {
return _commandRunner.get();
}
executor::TaskExecutor* getExecutor() const {
return _executor.get();
}
void reload();
/**
* Returns shared pointer to shard object with given shard id.
*/
std::shared_ptr<Shard> getShard(const ShardId& shardId);
/**
* Lookup shard by replica set name. Returns nullptr if the name can't be found.
* Note: this doesn't refresh the table if the name isn't found, so it's possible that a
* newly added shard/Replica Set may not be found.
*/
std::shared_ptr<Shard> lookupRSName(const std::string& name) const;
void remove(const ShardId& id);
void getAllShardIds(std::vector<ShardId>* all) const;
void toBSON(BSONObjBuilder* result);
/**
* Executes 'find' command against the specified host and fetches *all* the results that
* the host will return until there are no more or until an error is returned.
*
* Returns either the complete set of results or an error, never partial results.
*
* Note: should never be used outside of CatalogManagerReplicaSet or DistLockCatalogImpl.
*/
StatusWith<std::vector<BSONObj>> exhaustiveFind(const HostAndPort& host,
const NamespaceString& nss,
const BSONObj& query,
boost::optional<int> limit);
/**
* Runs a command against the specified host and returns the result.
*/
StatusWith<BSONObj> runCommand(const HostAndPort& host,
const std::string& dbName,
const BSONObj& cmdObj);
private:
typedef std::map<ShardId, std::shared_ptr<Shard>> ShardMap;
/**
* Creates a shard based on the specified information and puts it into the lookup maps.
*/
void _addShard_inlock(const ShardType& shardType);
/**
* Adds the "config" shard (representing the config server) to the shard registry.
*/
void _addConfigShard_inlock();
std::shared_ptr<Shard> _findUsingLookUp(const ShardId& shardId);
// Factory to obtain remote command targeters for shards
const std::unique_ptr<RemoteCommandTargeterFactory> _targeterFactory;
// API to run remote commands to shards in a synchronous manner
const std::unique_ptr<RemoteCommandRunner> _commandRunner;
// Executor for scheduling work and remote commands to shards that run in an asynchronous
// manner.
const std::unique_ptr<executor::TaskExecutor> _executor;
// Catalog manager from which to load the shard information. Not owned and must outlive
// the shard registry object.
CatalogManager* const _catalogManager;
// Protects the maps below
mutable std::mutex _mutex;
// Map of both shardName -> Shard and hostName -> Shard
ShardMap _lookup;
// TODO: These should eventually disappear and become parts of Shard
// Map from all hosts within a replica set to the shard representing this replica set
ShardMap _rsLookup;
};
} // namespace mongo
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