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/**
* Copyright (C) 2018-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.
*/
#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kQuery
#include "mongo/platform/basic.h"
#include "mongo/db/pipeline/document_source_out.h"
#include <fmt/format.h>
#include "mongo/db/curop_failpoint_helpers.h"
#include "mongo/db/ops/write_ops.h"
#include "mongo/db/pipeline/document_path_support.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/util/destructor_guard.h"
#include "mongo/util/log.h"
namespace mongo {
using namespace fmt::literals;
static AtomicWord<unsigned> aggOutCounter;
MONGO_FAIL_POINT_DEFINE(hangWhileBuildingDocumentSourceOutBatch);
REGISTER_DOCUMENT_SOURCE(out,
DocumentSourceOut::LiteParsed::parse,
DocumentSourceOut::createFromBson);
DocumentSourceOut::~DocumentSourceOut() {
DESTRUCTOR_GUARD(
// Make sure we drop the temp collection if anything goes wrong. Errors are ignored
// here because nothing can be done about them. Additionally, if this fails and the
// collection is left behind, it will be cleaned up next time the server is started.
if (_tempNs.size()) {
auto cleanupClient =
pExpCtx->opCtx->getServiceContext()->makeClient("$out_replace_coll_cleanup");
AlternativeClientRegion acr(cleanupClient);
// Create a new operation context so that any interrupts on the current operation will
// not affect the dropCollection operation below.
auto cleanupOpCtx = cc().makeOperationContext();
DocumentSourceWriteBlock writeBlock(cleanupOpCtx.get());
// Reset the operation context back to original once dropCollection is done.
ON_BLOCK_EXIT(
[this] { pExpCtx->mongoProcessInterface->setOperationContext(pExpCtx->opCtx); });
pExpCtx->mongoProcessInterface->setOperationContext(cleanupOpCtx.get());
pExpCtx->mongoProcessInterface->directClient()->dropCollection(_tempNs.ns());
});
}
std::unique_ptr<DocumentSourceOut::LiteParsed> DocumentSourceOut::LiteParsed::parse(
const AggregationRequest& request, const BSONElement& spec) {
uassert(ErrorCodes::TypeMismatch,
"{} stage requires a string argument, but found {}"_format(kStageName,
typeName(spec.type())),
spec.type() == BSONType::String);
NamespaceString targetNss{request.getNamespaceString().db(), spec.valueStringData()};
uassert(ErrorCodes::InvalidNamespace,
"Invalid {} target namespace, {}"_format(kStageName, targetNss.ns()),
targetNss.isValid());
ActionSet actions{ActionType::insert, ActionType::remove};
if (request.shouldBypassDocumentValidation()) {
actions.addAction(ActionType::bypassDocumentValidation);
}
PrivilegeVector privileges{Privilege(ResourcePattern::forExactNamespace(targetNss), actions)};
return std::make_unique<DocumentSourceOut::LiteParsed>(std::move(targetNss),
std::move(privileges));
}
void DocumentSourceOut::initialize() {
DocumentSourceWriteBlock writeBlock(pExpCtx->opCtx);
DBClientBase* conn = pExpCtx->mongoProcessInterface->directClient();
const auto& outputNs = getOutputNs();
_tempNs = NamespaceString(str::stream()
<< outputNs.db() << ".tmp.agg_out." << aggOutCounter.addAndFetch(1));
// Save the original collection options and index specs so we can check they didn't change
// during computation.
_originalOutOptions = pExpCtx->mongoProcessInterface->getCollectionOptions(outputNs);
_originalIndexes = conn->getIndexSpecs(outputNs);
// Check if it's capped to make sure we have a chance of succeeding before we do all the work.
// If the collection becomes capped during processing, the collection options will have changed,
// and the $out will fail.
uassert(17152,
"namespace '{}' is capped so it can't be used for {}"_format(outputNs.ns(), kStageName),
_originalOutOptions["capped"].eoo());
// We will write all results into a temporary collection, then rename the temporary
// collection to be the target collection once we are done.
_tempNs = NamespaceString(str::stream()
<< outputNs.db() << ".tmp.agg_out." << aggOutCounter.addAndFetch(1));
// Create temp collection, copying options from the existing output collection if any.
{
BSONObjBuilder cmd;
cmd << "create" << _tempNs.coll();
cmd << "temp" << true;
cmd.appendElementsUnique(_originalOutOptions);
BSONObj info;
uassert(16994,
"failed to create temporary {} collection '{}': {}"_format(
kStageName, _tempNs.ns(), getStatusFromCommandResult(info).reason()),
conn->runCommand(outputNs.db().toString(), cmd.done(), info));
}
if (_originalIndexes.empty()) {
return;
}
// Copy the indexes of the output collection to the temp collection.
try {
std::vector<BSONObj> tempNsIndexes = {std::begin(_originalIndexes),
std::end(_originalIndexes)};
conn->createIndexes(_tempNs.ns(), tempNsIndexes);
} catch (DBException& ex) {
ex.addContext("Copying indexes for $out failed");
throw;
}
}
void DocumentSourceOut::finalize() {
DocumentSourceWriteBlock writeBlock(pExpCtx->opCtx);
const auto& outputNs = getOutputNs();
auto renameCommandObj =
BSON("renameCollection" << _tempNs.ns() << "to" << outputNs.ns() << "dropTarget" << true);
pExpCtx->mongoProcessInterface->renameIfOptionsAndIndexesHaveNotChanged(
pExpCtx->opCtx, renameCommandObj, outputNs, _originalOutOptions, _originalIndexes);
// The rename succeeded, so the temp collection no longer exists.
_tempNs = {};
}
boost::intrusive_ptr<DocumentSource> DocumentSourceOut::create(
NamespaceString outputNs, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
// TODO (SERVER-36832): Allow this combination.
uassert(50939,
"{} is not supported when the output collection is in a different "
"database"_format(kStageName),
outputNs.db() == expCtx->ns.db());
uassert(ErrorCodes::OperationNotSupportedInTransaction,
"{} cannot be used in a transaction"_format(kStageName),
!expCtx->inMultiDocumentTransaction);
auto readConcernLevel = repl::ReadConcernArgs::get(expCtx->opCtx).getLevel();
uassert(ErrorCodes::InvalidOptions,
"{} cannot be used with a 'linearizable' read concern level"_format(kStageName),
readConcernLevel != repl::ReadConcernLevel::kLinearizableReadConcern);
uassert(ErrorCodes::InvalidNamespace,
"Invalid {} target namespace, {}"_format(kStageName, outputNs.ns()),
outputNs.isValid());
uassert(17017,
"{} is not supported to an existing *sharded* output collection"_format(kStageName),
!expCtx->mongoProcessInterface->isSharded(expCtx->opCtx, outputNs));
uassert(17385,
"Can't {} to special collection: {}"_format(kStageName, outputNs.coll()),
!outputNs.isSystem());
return new DocumentSourceOut(std::move(outputNs), expCtx);
}
boost::intrusive_ptr<DocumentSource> DocumentSourceOut::createFromBson(
BSONElement elem, const boost::intrusive_ptr<ExpressionContext>& expCtx) {
uassert(16990,
"{} only supports a string argument, but found {}"_format(kStageName,
typeName(elem.type())),
elem.type() == BSONType::String);
return create({expCtx->ns.db(), elem.str()}, expCtx);
}
Value DocumentSourceOut::serialize(boost::optional<ExplainOptions::Verbosity> explain) const {
massert(17000,
"{} shouldn't have different db than input"_format(kStageName),
_outputNs.db() == pExpCtx->ns.db());
return Value(DOC(getSourceName() << _outputNs.coll()));
}
void DocumentSourceOut::waitWhileFailPointEnabled() {
CurOpFailpointHelpers::waitWhileFailPointEnabled(
&hangWhileBuildingDocumentSourceOutBatch,
pExpCtx->opCtx,
"hangWhileBuildingDocumentSourceOutBatch",
[]() {
log() << "Hanging aggregation due to 'hangWhileBuildingDocumentSourceOutBatch' "
<< "failpoint";
});
}
} // namespace mongo
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