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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.
*/
#include "mongo/db/views/view_catalog_helpers.h"
#include "mongo/db/catalog/collection_catalog.h"
#include "mongo/db/curop.h"
#include "mongo/db/pipeline/aggregate_command_gen.h"
#include "mongo/db/pipeline/document_source.h"
#include "mongo/db/pipeline/expression_context.h"
#include "mongo/db/pipeline/lite_parsed_pipeline.h"
#include "mongo/db/pipeline/pipeline.h"
#include "mongo/db/pipeline/process_interface/stub_mongo_process_interface.h"
#include "mongo/db/views/view_graph.h"
namespace mongo {
namespace view_catalog_helpers {
StatusWith<stdx::unordered_set<NamespaceString>> validatePipeline(OperationContext* opCtx,
const ViewDefinition& viewDef) {
const LiteParsedPipeline liteParsedPipeline(viewDef.viewOn(), viewDef.pipeline());
const auto involvedNamespaces = liteParsedPipeline.getInvolvedNamespaces();
// The API version pipeline validation should be skipped for time-series view because of
// following reasons:
// - the view pipeline is not created by (or visible to) the end-user and should be skipped.
// - the view pipeline can have stages that are not allowed in stable API version '1' eg.
// '$_internalUnpackBucket'.
bool performApiVersionChecks = !viewDef.timeseries();
liteParsedPipeline.validate(opCtx, performApiVersionChecks);
// Verify that this is a legitimate pipeline specification by making sure it parses
// correctly. In order to parse a pipeline we need to resolve any namespaces involved to a
// collection and a pipeline, but in this case we don't need this map to be accurate since
// we will not be evaluating the pipeline.
StringMap<ExpressionContext::ResolvedNamespace> resolvedNamespaces;
for (auto&& nss : involvedNamespaces) {
resolvedNamespaces[nss.coll()] = {nss, {}};
}
boost::intrusive_ptr<ExpressionContext> expCtx =
new ExpressionContext(opCtx,
AggregateCommandRequest(viewDef.viewOn(), viewDef.pipeline()),
CollatorInterface::cloneCollator(viewDef.defaultCollator()),
// We can use a stub MongoProcessInterface because we are only parsing
// the Pipeline for validation here. We won't do anything with the
// pipeline that will require a real implementation.
std::make_shared<StubMongoProcessInterface>(),
std::move(resolvedNamespaces),
boost::none);
// If the feature compatibility version is not kLatest, and we are validating features as
// primary, ban the use of new agg features introduced in kLatest to prevent them from being
// persisted in the catalog.
// (Generic FCV reference): This FCV check should exist across LTS binary versions.
multiversion::FeatureCompatibilityVersion fcv;
if (serverGlobalParams.validateFeaturesAsPrimary.load() &&
serverGlobalParams.featureCompatibility.isLessThan(multiversion::GenericFCV::kLatest,
&fcv)) {
expCtx->maxFeatureCompatibilityVersion = fcv;
}
// The pipeline parser needs to know that we're parsing a pipeline for a view definition
// to apply some additional checks.
expCtx->isParsingViewDefinition = true;
try {
auto pipeline =
Pipeline::parse(viewDef.pipeline(), std::move(expCtx), [&](const Pipeline& pipeline) {
// Validate that the view pipeline does not contain any ineligible stages.
const auto& sources = pipeline.getSources();
const auto firstPersistentStage =
std::find_if(sources.begin(), sources.end(), [](const auto& source) {
return source->constraints().writesPersistentData();
});
uassert(ErrorCodes::OptionNotSupportedOnView,
str::stream()
<< "The aggregation stage "
<< firstPersistentStage->get()->getSourceName() << " in location "
<< std::distance(sources.begin(), firstPersistentStage)
<< " of the pipeline cannot be used in the view definition of "
<< viewDef.name().ns() << " because it writes to disk",
firstPersistentStage == sources.end());
uassert(ErrorCodes::OptionNotSupportedOnView,
"$changeStream cannot be used in a view definition",
sources.empty() || !sources.front()->constraints().isChangeStreamStage());
std::for_each(sources.begin(), sources.end(), [](auto& stage) {
uassert(ErrorCodes::InvalidNamespace,
str::stream() << "'" << stage->getSourceName()
<< "' cannot be used in a view definition",
!stage->constraints().isIndependentOfAnyCollection);
});
});
} catch (const DBException& ex) {
return ex.toStatus();
}
return std::move(involvedNamespaces);
}
StatusWith<ResolvedView> resolveView(OperationContext* opCtx,
std::shared_ptr<const CollectionCatalog> catalog,
const NamespaceString& nss,
boost::optional<BSONObj> timeSeriesCollator) {
// Points to the name of the most resolved namespace.
const NamespaceString* resolvedNss = &nss;
// Holds the combination of all the resolved views.
std::vector<BSONObj> resolvedPipeline;
// If the catalog has not been tampered with, all views seen during the resolution will have
// the same collation. As an optimization, we fill out the collation spec only once.
boost::optional<BSONObj> collation;
// The last seen view definition, which owns the NamespaceString pointed to by
// 'resolvedNss'.
std::shared_ptr<ViewDefinition> lastViewDefinition;
std::vector<NamespaceString> dependencyChain{nss};
int depth = 0;
boost::optional<bool> mixedData = boost::none;
boost::optional<TimeseriesOptions> tsOptions = boost::none;
for (; depth < ViewGraph::kMaxViewDepth; depth++) {
auto view = catalog->lookupView(opCtx, *resolvedNss);
if (!view) {
// Return error status if pipeline is too large.
int pipelineSize = 0;
for (auto obj : resolvedPipeline) {
pipelineSize += obj.objsize();
}
if (pipelineSize > ViewGraph::kMaxViewPipelineSizeBytes) {
return {ErrorCodes::ViewPipelineMaxSizeExceeded,
str::stream() << "View pipeline exceeds maximum size; maximum size is "
<< ViewGraph::kMaxViewPipelineSizeBytes};
}
auto curOp = CurOp::get(opCtx);
curOp->debug().addResolvedViews(dependencyChain, resolvedPipeline);
return StatusWith<ResolvedView>(
{*resolvedNss,
std::move(resolvedPipeline),
collation ? std::move(collation.get()) : CollationSpec::kSimpleSpec,
tsOptions,
mixedData});
}
resolvedNss = &view->viewOn();
if (storageGlobalParams.restore) {
// During a selective restore procedure, skip checking options as the collection may no
// longer exist.
continue;
}
if (view->timeseries()) {
// Use the lock-free collection lookup, to ensure compatibility with lock-free read
// operations.
auto tsCollection = catalog->lookupCollectionByNamespaceForRead(opCtx, *resolvedNss);
uassert(6067201,
str::stream() << "expected time-series buckets collection " << *resolvedNss
<< " to exist",
tsCollection);
if (tsCollection) {
mixedData = tsCollection->getTimeseriesBucketsMayHaveMixedSchemaData();
tsOptions = tsCollection->getTimeseriesOptions();
}
}
dependencyChain.push_back(*resolvedNss);
if (!collation) {
if (timeSeriesCollator) {
collation = *timeSeriesCollator;
} else {
collation = view->defaultCollator() ? view->defaultCollator()->getSpec().toBSON()
: CollationSpec::kSimpleSpec;
}
}
// Prepend the underlying view's pipeline to the current working pipeline.
const std::vector<BSONObj>& toPrepend = view->pipeline();
resolvedPipeline.insert(resolvedPipeline.begin(), toPrepend.begin(), toPrepend.end());
// If the first stage is a $collStats, then we return early with the viewOn namespace.
if (toPrepend.size() > 0 && !toPrepend[0]["$collStats"].eoo()) {
auto curOp = CurOp::get(opCtx);
curOp->debug().addResolvedViews(dependencyChain, resolvedPipeline);
return StatusWith<ResolvedView>(
{*resolvedNss, std::move(resolvedPipeline), std::move(collation.get())});
}
}
if (depth >= ViewGraph::kMaxViewDepth) {
return {ErrorCodes::ViewDepthLimitExceeded,
str::stream() << "View depth too deep or view cycle detected; maximum depth is "
<< ViewGraph::kMaxViewDepth};
}
MONGO_UNREACHABLE;
}
} // namespace view_catalog_helpers
} // namespace mongo
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