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/**
* Copyright (C) 2015 10gen 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.
*/
#include <string>
#include <tuple>
#include <vector>
#include "mongo/base/string_data.h"
#include "mongo/db/commands.h"
#include "mongo/s/client/shard.h"
namespace mongo {
class BSONObj;
class BSONObjBuilder;
class OperationContext;
/**
* Logic for commands that simply map out to all shards then fold the results into
* a single response.
*
* All shards are contacted in parallel.
*
* When extending, don't override run() - but rather aggregateResults(). If you need
* to implement some kind of fall back logic for multiversion clusters,
* override specialErrorHandler().
*/
class RunOnAllShardsCommand : public Command {
public:
RunOnAllShardsCommand(const char* name,
const char* oldName = NULL,
bool useShardConn = false,
bool implicitCreateDb = false);
bool slaveOk() const override {
return true;
}
bool adminOnly() const override {
return false;
}
bool isWriteCommandForConfigServer() const override {
return false;
}
// The StringData contains the shard ident.
// This can be used to create an instance of Shard
using ShardAndReply = std::tuple<StringData, BSONObj>;
virtual void aggregateResults(const std::vector<ShardAndReply>& results,
BSONObjBuilder& output);
// The default implementation is the identity function.
virtual BSONObj specialErrorHandler(const std::string& server,
const std::string& db,
const BSONObj& cmdObj,
const BSONObj& originalResult) const;
// The default implementation uses all shards.
virtual void getShardIds(OperationContext* txn,
const std::string& db,
BSONObj& cmdObj,
std::vector<ShardId>& shardIds);
bool run(OperationContext* txn,
const std::string& db,
BSONObj& cmdObj,
int options,
std::string& errmsg,
BSONObjBuilder& output) final;
private:
// Use ShardConnection as opposed to ScopedDbConnection
const bool _useShardConn;
// Whether the requested database should be created implicitly
const bool _implicitCreateDb;
};
} // namespace mongo
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