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/**
* Copyright (C) 2017 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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kQuery
#include "mongo/s/query/router_stage_update_on_add_shard.h"
#include <algorithm>
#include "mongo/base/checked_cast.h"
#include "mongo/db/pipeline/document_source_change_stream.h"
#include "mongo/executor/task_executor_pool.h"
#include "mongo/s/client/shard_registry.h"
#include "mongo/s/grid.h"
#include "mongo/s/query/establish_cursors.h"
#include "mongo/s/query/router_stage_merge.h"
#include "mongo/util/log.h"
namespace mongo {
namespace {
// Returns true if the change stream document has an 'operationType' of 'newShardDetected'.
bool needsUpdate(const StatusWith<ClusterQueryResult>& childResult) {
if (!childResult.isOK() || childResult.getValue().isEOF()) {
return false;
}
return ((*childResult.getValue().getResult())[DocumentSourceChangeStream::kOperationTypeField]
.str() == DocumentSourceChangeStream::kNewShardDetectedOpType);
}
}
RouterStageUpdateOnAddShard::RouterStageUpdateOnAddShard(OperationContext* opCtx,
executor::TaskExecutor* executor,
ClusterClientCursorParams* params,
std::vector<ShardId> shardIds,
BSONObj cmdToRunOnNewShards)
: RouterExecStage(opCtx, stdx::make_unique<RouterStageMerge>(opCtx, executor, params)),
_params(params),
_shardIds(std::move(shardIds)),
_cmdToRunOnNewShards(cmdToRunOnNewShards) {}
StatusWith<ClusterQueryResult> RouterStageUpdateOnAddShard::next(
RouterExecStage::ExecContext execContext) {
auto childStage = getChildStage();
auto childResult = childStage->next(execContext);
while (needsUpdate(childResult)) {
addNewShardCursors(*childResult.getValue().getResult());
childResult = childStage->next(execContext);
}
return childResult;
}
void RouterStageUpdateOnAddShard::addNewShardCursors(BSONObj newShardDetectedObj) {
checked_cast<RouterStageMerge*>(getChildStage())
->addNewShardCursors(establishShardCursorsOnNewShards(newShardDetectedObj));
}
std::vector<RemoteCursor> RouterStageUpdateOnAddShard::establishShardCursorsOnNewShards(
const BSONObj& newShardDetectedObj) {
auto* opCtx = getOpCtx();
// Reload the shard registry. We need to ensure a reload initiated after calling this method
// caused the reload, otherwise we aren't guaranteed to get all the new shards.
auto* shardRegistry = Grid::get(opCtx)->shardRegistry();
if (!shardRegistry->reload(opCtx)) {
// A 'false' return from shardRegistry.reload() means a reload was already in progress and
// it completed before reload() returned. So another reload(), regardless of return
// value, will ensure a reload started after the first call to reload().
shardRegistry->reload(opCtx);
}
std::vector<ShardId> shardIds, newShardIds;
shardRegistry->getAllShardIdsNoReload(&shardIds);
std::sort(_shardIds.begin(), _shardIds.end());
std::sort(shardIds.begin(), shardIds.end());
std::set_difference(shardIds.begin(),
shardIds.end(),
_shardIds.begin(),
_shardIds.end(),
std::back_inserter(newShardIds));
auto cmdObj = DocumentSourceChangeStream::replaceResumeTokenInCommand(
_cmdToRunOnNewShards,
newShardDetectedObj[DocumentSourceChangeStream::kIdField].embeddedObject());
std::vector<std::pair<ShardId, BSONObj>> requests;
for (const auto& shardId : newShardIds) {
requests.emplace_back(shardId, cmdObj);
_shardIds.push_back(shardId);
}
const bool allowPartialResults = false; // partial results are not allowed
return establishCursors(opCtx,
Grid::get(opCtx)->getExecutorPool()->getArbitraryExecutor(),
_params->nsString,
_params->readPreference.value_or(ReadPreferenceSetting()),
requests,
allowPartialResults);
}
} // namespace mongo
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