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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.
*/
#pragma once
#include <boost/intrusive_ptr.hpp>
#include <boost/optional.hpp>
#include <list>
#include <memory>
#include <string>
#include <vector>
#include "mongo/base/shim.h"
#include "mongo/client/dbclient_base.h"
#include "mongo/db/collection_index_usage_tracker.h"
#include "mongo/db/generic_cursor.h"
#include "mongo/db/matcher/expression.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/ops/write_ops_exec.h"
#include "mongo/db/ops/write_ops_parsers.h"
#include "mongo/db/pipeline/document.h"
#include "mongo/db/pipeline/field_path.h"
#include "mongo/db/pipeline/lite_parsed_document_source.h"
#include "mongo/db/pipeline/value.h"
#include "mongo/db/query/explain_options.h"
#include "mongo/db/repl/oplog_entry.h"
#include "mongo/db/resource_yielder.h"
#include "mongo/db/storage/backup_cursor_state.h"
#include "mongo/s/chunk_version.h"
namespace mongo {
class ShardFilterer;
class ExpressionContext;
class Pipeline;
class PipelineDeleter;
class TransactionHistoryIteratorBase;
/**
* Any functionality needed by an aggregation stage that is either context specific to a mongod or
* mongos process, or is only compiled in to one of those two binaries must be accessed via this
* interface. This allows all DocumentSources to be parsed on either mongos or mongod, but only
* executable where it makes sense.
*/
class MongoProcessInterface {
public:
/**
* Storage for a batch of BSON Objects to be updated in the write namespace. For each element
* in the batch we store a tuple of the folliwng elements:
* 1. BSONObj - specifies the query that identifies a document in the to collection to be
* updated.
* 2. write_ops::UpdateModification - either the new document we want to upsert or insert into
* the collection (i.e. a 'classic' replacement update), or the pipeline to run to compute
* the new document.
* 3. boost::optional<BSONObj> - for pipeline-style updated, specifies variables that can be
* referred to in the pipeline performing the custom update.
*/
using BatchObject =
std::tuple<BSONObj, write_ops::UpdateModification, boost::optional<BSONObj>>;
using BatchedObjects = std::vector<BatchObject>;
enum class CurrentOpConnectionsMode { kIncludeIdle, kExcludeIdle };
enum class CurrentOpUserMode { kIncludeAll, kExcludeOthers };
enum class CurrentOpTruncateMode { kNoTruncation, kTruncateOps };
enum class CurrentOpLocalOpsMode { kLocalMongosOps, kRemoteShardOps };
enum class CurrentOpSessionsMode { kIncludeIdle, kExcludeIdle };
enum class CurrentOpCursorMode { kIncludeCursors, kExcludeCursors };
enum class CurrentOpBacktraceMode { kIncludeBacktrace, kExcludeBacktrace };
/**
* Factory function to create MongoProcessInterface of the right type. The implementation will
* be installed by a lib higher up in the link graph depending on the application type.
*/
static MONGO_DECLARE_SHIM(
(OperationContext * opCtx)->std::shared_ptr<MongoProcessInterface>) create;
struct MakePipelineOptions {
MakePipelineOptions(){};
bool optimize = true;
bool attachCursorSource = true;
};
/**
* This structure holds the result of a batched update operation, such as the number of
* documents that matched the query predicate, and the number of documents modified by the
* update operation.
*/
struct UpdateResult {
int64_t nMatched{0};
int64_t nModified{0};
};
virtual ~MongoProcessInterface(){};
/**
* Sets the OperationContext of the DBDirectClient returned by directClient(). This method must
* be called after updating the 'opCtx' member of the ExpressionContext associated with the
* document source.
*/
virtual void setOperationContext(OperationContext* opCtx) = 0;
/**
* Always returns a DBDirectClient. The return type in the function signature is a DBClientBase*
* because DBDirectClient isn't linked into mongos.
*/
virtual DBClientBase* directClient() = 0;
/**
* Creates a new TransactionHistoryIterator object. Only applicable in processes which support
* locally traversing the oplog.
*/
virtual std::unique_ptr<TransactionHistoryIteratorBase> createTransactionHistoryIterator(
repl::OpTime time) const = 0;
/**
* Note that in some rare cases this could return a false negative but will never return a false
* positive. This method will be fixed in the future once it becomes possible to avoid false
* negatives.
*/
virtual bool isSharded(OperationContext* opCtx, const NamespaceString& ns) = 0;
/**
* Inserts 'objs' into 'ns' and returns an error Status if the insert fails. If 'targetEpoch' is
* set, throws ErrorCodes::StaleEpoch if the targeted collection does not have the same epoch or
* the epoch changes during the course of the insert.
*/
virtual Status insert(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& ns,
std::vector<BSONObj>&& objs,
const WriteConcernOptions& wc,
boost::optional<OID> targetEpoch) = 0;
/**
* Updates the documents matching 'queries' with the objects 'updates'. Returns an error Status
* if any of the updates fail, otherwise returns an 'UpdateResult' objects with the details of
* the update operation. If 'targetEpoch' is set, throws ErrorCodes::StaleEpoch if the targeted
* collection does not have the same epoch, or if the epoch changes during the update.
*/
virtual StatusWith<UpdateResult> update(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& ns,
BatchedObjects&& batch,
const WriteConcernOptions& wc,
bool upsert,
bool multi,
boost::optional<OID> targetEpoch) = 0;
virtual CollectionIndexUsageMap getIndexStats(OperationContext* opCtx,
const NamespaceString& ns) = 0;
/**
* Appends operation latency statistics for collection "nss" to "builder"
*/
virtual void appendLatencyStats(OperationContext* opCtx,
const NamespaceString& nss,
bool includeHistograms,
BSONObjBuilder* builder) const = 0;
/**
* Appends storage statistics for collection "nss" to "builder"
*/
virtual Status appendStorageStats(OperationContext* opCtx,
const NamespaceString& nss,
const BSONObj& param,
BSONObjBuilder* builder) const = 0;
/**
* Appends the record count for collection "nss" to "builder".
*/
virtual Status appendRecordCount(OperationContext* opCtx,
const NamespaceString& nss,
BSONObjBuilder* builder) const = 0;
/**
* Appends the exec stats for the collection 'nss' to 'builder'.
*/
virtual Status appendQueryExecStats(OperationContext* opCtx,
const NamespaceString& nss,
BSONObjBuilder* builder) const = 0;
/**
* Gets the collection options for the collection given by 'nss'. Throws
* ErrorCodes::CommandNotSupportedOnView if 'nss' describes a view. Future callers may want to
* parameterize this behavior.
*/
virtual BSONObj getCollectionOptions(const NamespaceString& nss) = 0;
/**
* Performs the given rename command if the collection given by 'targetNs' has the same options
* as specified in 'originalCollectionOptions', and has the same indexes as 'originalIndexes'.
*
* Throws an exception if the collection options and/or indexes are different.
*/
virtual void renameIfOptionsAndIndexesHaveNotChanged(
OperationContext* opCtx,
const BSONObj& renameCommandObj,
const NamespaceString& targetNs,
const BSONObj& originalCollectionOptions,
const std::list<BSONObj>& originalIndexes) = 0;
/**
* Parses a Pipeline from a vector of BSONObjs representing DocumentSources. The state of the
* returned pipeline will depend upon the supplied MakePipelineOptions:
* - The boolean opts.optimize determines whether the pipeline will be optimized.
* - If opts.attachCursorSource is false, the pipeline will be returned without attempting to
* add an initial cursor source.
*
* This function throws if parsing the pipeline failed.
*/
virtual std::unique_ptr<Pipeline, PipelineDeleter> makePipeline(
const std::vector<BSONObj>& rawPipeline,
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const MakePipelineOptions opts = MakePipelineOptions{}) = 0;
/**
* Accepts a pipeline and returns a new one which will draw input from the underlying
* collection. Performs no further optimization of the pipeline. NamespaceNotFound will be
* thrown if ExpressionContext has a UUID and that UUID doesn't exist anymore. That should be
* the only case where NamespaceNotFound is returned.
*
* This function takes ownership of the 'pipeline' argument as if it were a unique_ptr.
* Changing it to a unique_ptr introduces a circular dependency on certain platforms where the
* compiler expects to find an implementation of PipelineDeleter.
*/
virtual std::unique_ptr<Pipeline, PipelineDeleter> attachCursorSourceToPipeline(
const boost::intrusive_ptr<ExpressionContext>& expCtx, Pipeline* pipeline) = 0;
/**
* Accepts a pipeline and returns a new one which will draw input from the underlying
* collection _locally_. Trying to run this method on mongos is a programming error. Running
* this method on a shard server will only return results which match the pipeline on that
* shard.
* Performs no further optimization of the pipeline. NamespaceNotFound will be
* thrown if ExpressionContext has a UUID and that UUID doesn't exist anymore. That should be
* the only case where NamespaceNotFound is returned.
*
* This function takes ownership of the 'pipeline' argument as if it were a unique_ptr.
* Changing it to a unique_ptr introduces a circular dependency on certain platforms where the
* compiler expects to find an implementation of PipelineDeleter.
*/
virtual std::unique_ptr<Pipeline, PipelineDeleter> attachCursorSourceToPipelineForLocalRead(
const boost::intrusive_ptr<ExpressionContext>& expCtx, Pipeline* pipeline) = 0;
/**
* Produces a ShardFilterer. May return null.
*/
virtual std::unique_ptr<ShardFilterer> getShardFilterer(
const boost::intrusive_ptr<ExpressionContext>& expCtx) const = 0;
/**
* Returns a vector of owned BSONObjs, each of which contains details of an in-progress
* operation or, optionally, an idle connection. If userMode is kIncludeAllUsers, report
* operations for all authenticated users; otherwise, report only the current user's operations.
*/
virtual std::vector<BSONObj> getCurrentOps(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
CurrentOpConnectionsMode connMode,
CurrentOpSessionsMode sessionMode,
CurrentOpUserMode userMode,
CurrentOpTruncateMode,
CurrentOpCursorMode,
CurrentOpBacktraceMode) const = 0;
/**
* Returns the name of the local shard if sharding is enabled, or an empty string.
*/
virtual std::string getShardName(OperationContext* opCtx) const = 0;
/**
* Returns the fields of the document key (in order) for the collection corresponding to 'uuid',
* including the shard key and _id. If _id is not in the shard key, it is added last. If the
* collection is not sharded or no longer exists, returns only _id. Also returns a boolean that
* indicates whether the returned fields of the document key are final and will never change for
* the given collection, either because the collection was dropped or has become sharded.
*
* This method is meant to be called from a mongod which owns at least one chunk for this
* collection. It will inspect the CollectionShardingState, not the CatalogCache. If asked about
* a collection not hosted on this shard, the answer will be incorrect.
*/
virtual std::pair<std::vector<FieldPath>, bool> collectDocumentKeyFieldsForHostedCollection(
OperationContext* opCtx, const NamespaceString&, UUID) const = 0;
/**
* Returns the fields of the document key (in order) for the collection 'nss', according to the
* CatalogCache. The document key fields are the shard key (if sharded) and the _id (if not
* already in the shard key). If _id is not in the shard key, it is added last. If the
* collection is not sharded or is not known to exist, returns only _id. Does not refresh the
* CatalogCache.
*/
virtual std::vector<FieldPath> collectDocumentKeyFieldsActingAsRouter(
OperationContext* opCtx, const NamespaceString&) const = 0;
/**
* Returns zero or one documents with the document key 'documentKey'. 'documentKey' is treated
* as a unique identifier of a document, and may include an _id or all fields from the shard key
* and an _id. Throws if more than one match was found. Returns boost::none if no matching
* documents were found, including cases where the given namespace does not exist.
*/
virtual boost::optional<Document> lookupSingleDocument(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& nss,
UUID,
const Document& documentKey,
boost::optional<BSONObj> readConcern,
bool allowSpeculativeMajorityRead = false) = 0;
/**
* Returns a vector of all idle (non-pinned) local cursors.
*/
virtual std::vector<GenericCursor> getIdleCursors(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
CurrentOpUserMode userMode) const = 0;
/**
* The following methods forward to the BackupCursorHooks decorating the ServiceContext.
*/
virtual BackupCursorState openBackupCursor(OperationContext* opCtx) = 0;
virtual void closeBackupCursor(OperationContext* opCtx, const UUID& backupId) = 0;
virtual BackupCursorExtendState extendBackupCursor(OperationContext* opCtx,
const UUID& backupId,
const Timestamp& extendTo) = 0;
/**
* Returns a vector of BSON objects, where each entry in the vector describes a plan cache entry
* inside the cache for the given namespace. Only those entries which match the supplied
* MatchExpression are returned.
*/
virtual std::vector<BSONObj> getMatchingPlanCacheEntryStats(OperationContext*,
const NamespaceString&,
const MatchExpression*) const = 0;
/**
* Returns true if there is an index on 'nss' with properties that will guarantee that a
* document with non-array values for each of 'fieldPaths' will have at most one matching
* document in 'nss'.
*
* Specifically, such an index must include all the fields, be unique, not be a partial index,
* and match the operation's collation as given by 'expCtx'.
*/
virtual bool fieldsHaveSupportingUniqueIndex(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& nss,
const std::set<FieldPath>& fieldPaths) const = 0;
/**
* Refreshes the CatalogCache entry for the namespace 'nss', and returns the epoch associated
* with that namespace, if any. Note that this refresh will not necessarily force a new
* request to be sent to the config servers. If another thread has already requested a refresh,
* it will instead wait for that response.
*/
virtual boost::optional<ChunkVersion> refreshAndGetCollectionVersion(
const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& nss) const = 0;
/**
* Consults the CatalogCache to determine if this node has routing information for the
* collection given by 'nss' which reports the same epoch as given by 'targetCollectionVersion'.
* Major and minor versions in 'targetCollectionVersion' are ignored.
*/
virtual void checkRoutingInfoEpochOrThrow(const boost::intrusive_ptr<ExpressionContext>& expCtx,
const NamespaceString& nss,
ChunkVersion targetCollectionVersion) const = 0;
virtual std::unique_ptr<ResourceYielder> getResourceYielder() const = 0;
/**
* If the user supplied the 'fields' array, ensures that it can be used to uniquely identify a
* document. Otherwise, picks a default unique key, which can be either the "_id" field, or
* or a shard key, depending on the 'outputNs' collection type and the server type (mongod or
* mongos). Also returns an optional ChunkVersion, populated with the version stored in the
* sharding catalog when we asked for the shard key (on mongos only). On mongod, this is the
* value of the 'targetCollectionVersion' parameter, which is the target shard version of the
* collection, as sent by mongos.
*/
virtual std::pair<std::set<FieldPath>, boost::optional<ChunkVersion>>
ensureFieldsUniqueOrResolveDocumentKey(const boost::intrusive_ptr<ExpressionContext>& expCtx,
boost::optional<std::vector<std::string>> fields,
boost::optional<ChunkVersion> targetCollectionVersion,
const NamespaceString& outputNs) const = 0;
};
} // namespace mongo
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