701 lines
22 KiB
Go
701 lines
22 KiB
Go
// Copyright (C) MongoDB, Inc. 2017-present.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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package mongo
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import (
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"context"
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"errors"
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"fmt"
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"reflect"
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"strconv"
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"time"
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"go.mongodb.org/mongo-driver/bson"
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"go.mongodb.org/mongo-driver/bson/bsoncodec"
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"go.mongodb.org/mongo-driver/bson/primitive"
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"go.mongodb.org/mongo-driver/internal"
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"go.mongodb.org/mongo-driver/mongo/description"
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"go.mongodb.org/mongo-driver/mongo/options"
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"go.mongodb.org/mongo-driver/mongo/readconcern"
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"go.mongodb.org/mongo-driver/mongo/readpref"
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"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
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"go.mongodb.org/mongo-driver/x/mongo/driver"
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"go.mongodb.org/mongo-driver/x/mongo/driver/operation"
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"go.mongodb.org/mongo-driver/x/mongo/driver/session"
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)
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var (
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// ErrMissingResumeToken indicates that a change stream notification from the server did not contain a resume token.
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ErrMissingResumeToken = errors.New("cannot provide resume functionality when the resume token is missing")
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// ErrNilCursor indicates that the underlying cursor for the change stream is nil.
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ErrNilCursor = errors.New("cursor is nil")
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minResumableLabelWireVersion int32 = 9 // Wire version at which the server includes the resumable error label
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networkErrorLabel = "NetworkError"
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resumableErrorLabel = "ResumableChangeStreamError"
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errorCursorNotFound int32 = 43 // CursorNotFound error code
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// Allowlist of error codes that are considered resumable.
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resumableChangeStreamErrors = map[int32]struct{}{
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6: {}, // HostUnreachable
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7: {}, // HostNotFound
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89: {}, // NetworkTimeout
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91: {}, // ShutdownInProgress
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189: {}, // PrimarySteppedDown
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262: {}, // ExceededTimeLimit
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9001: {}, // SocketException
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10107: {}, // NotPrimary
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11600: {}, // InterruptedAtShutdown
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11602: {}, // InterruptedDueToReplStateChange
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13435: {}, // NotPrimaryNoSecondaryOK
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13436: {}, // NotPrimaryOrSecondary
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63: {}, // StaleShardVersion
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150: {}, // StaleEpoch
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13388: {}, // StaleConfig
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234: {}, // RetryChangeStream
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133: {}, // FailedToSatisfyReadPreference
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}
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)
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// ChangeStream is used to iterate over a stream of events. Each event can be decoded into a Go type via the Decode
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// method or accessed as raw BSON via the Current field. This type is not goroutine safe and must not be used
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// concurrently by multiple goroutines. For more information about change streams, see
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// https://www.mongodb.com/docs/manual/changeStreams/.
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type ChangeStream struct {
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// Current is the BSON bytes of the current event. This property is only valid until the next call to Next or
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// TryNext. If continued access is required, a copy must be made.
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Current bson.Raw
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aggregate *operation.Aggregate
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pipelineSlice []bsoncore.Document
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pipelineOptions map[string]bsoncore.Value
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cursor changeStreamCursor
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cursorOptions driver.CursorOptions
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batch []bsoncore.Document
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resumeToken bson.Raw
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err error
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sess *session.Client
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client *Client
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registry *bsoncodec.Registry
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streamType StreamType
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options *options.ChangeStreamOptions
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selector description.ServerSelector
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operationTime *primitive.Timestamp
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wireVersion *description.VersionRange
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}
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type changeStreamConfig struct {
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readConcern *readconcern.ReadConcern
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readPreference *readpref.ReadPref
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client *Client
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registry *bsoncodec.Registry
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streamType StreamType
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collectionName string
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databaseName string
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crypt driver.Crypt
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}
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func newChangeStream(ctx context.Context, config changeStreamConfig, pipeline interface{},
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opts ...*options.ChangeStreamOptions) (*ChangeStream, error) {
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if ctx == nil {
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ctx = context.Background()
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}
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cs := &ChangeStream{
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client: config.client,
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registry: config.registry,
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streamType: config.streamType,
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options: options.MergeChangeStreamOptions(opts...),
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selector: description.CompositeSelector([]description.ServerSelector{
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description.ReadPrefSelector(config.readPreference),
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description.LatencySelector(config.client.localThreshold),
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}),
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cursorOptions: config.client.createBaseCursorOptions(),
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}
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cs.sess = sessionFromContext(ctx)
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if cs.sess == nil && cs.client.sessionPool != nil {
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cs.sess, cs.err = session.NewClientSession(cs.client.sessionPool, cs.client.id, session.Implicit)
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if cs.err != nil {
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return nil, cs.Err()
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}
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}
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if cs.err = cs.client.validSession(cs.sess); cs.err != nil {
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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cs.aggregate = operation.NewAggregate(nil).
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ReadPreference(config.readPreference).ReadConcern(config.readConcern).
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Deployment(cs.client.deployment).ClusterClock(cs.client.clock).
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CommandMonitor(cs.client.monitor).Session(cs.sess).ServerSelector(cs.selector).Retry(driver.RetryNone).
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ServerAPI(cs.client.serverAPI).Crypt(config.crypt).Timeout(cs.client.timeout)
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if cs.options.Collation != nil {
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cs.aggregate.Collation(bsoncore.Document(cs.options.Collation.ToDocument()))
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}
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if comment := cs.options.Comment; comment != nil {
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cs.aggregate.Comment(*comment)
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commentVal, err := transformValue(cs.registry, comment, true, "comment")
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if err != nil {
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return nil, err
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}
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cs.cursorOptions.Comment = commentVal
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}
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if cs.options.BatchSize != nil {
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cs.aggregate.BatchSize(*cs.options.BatchSize)
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cs.cursorOptions.BatchSize = *cs.options.BatchSize
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}
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if cs.options.MaxAwaitTime != nil {
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cs.cursorOptions.MaxTimeMS = int64(*cs.options.MaxAwaitTime / time.Millisecond)
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}
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if cs.options.Custom != nil {
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// Marshal all custom options before passing to the initial aggregate. Return
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// any errors from Marshaling.
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customOptions := make(map[string]bsoncore.Value)
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for optionName, optionValue := range cs.options.Custom {
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bsonType, bsonData, err := bson.MarshalValueWithRegistry(cs.registry, optionValue)
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if err != nil {
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cs.err = err
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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optionValueBSON := bsoncore.Value{Type: bsonType, Data: bsonData}
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customOptions[optionName] = optionValueBSON
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}
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cs.aggregate.CustomOptions(customOptions)
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}
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if cs.options.CustomPipeline != nil {
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// Marshal all custom pipeline options before building pipeline slice. Return
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// any errors from Marshaling.
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cs.pipelineOptions = make(map[string]bsoncore.Value)
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for optionName, optionValue := range cs.options.CustomPipeline {
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bsonType, bsonData, err := bson.MarshalValueWithRegistry(cs.registry, optionValue)
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if err != nil {
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cs.err = err
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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optionValueBSON := bsoncore.Value{Type: bsonType, Data: bsonData}
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cs.pipelineOptions[optionName] = optionValueBSON
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}
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}
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switch cs.streamType {
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case ClientStream:
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cs.aggregate.Database("admin")
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case DatabaseStream:
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cs.aggregate.Database(config.databaseName)
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case CollectionStream:
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cs.aggregate.Collection(config.collectionName).Database(config.databaseName)
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default:
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closeImplicitSession(cs.sess)
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return nil, fmt.Errorf("must supply a valid StreamType in config, instead of %v", cs.streamType)
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}
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// When starting a change stream, cache startAfter as the first resume token if it is set. If not, cache
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// resumeAfter. If neither is set, do not cache a resume token.
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resumeToken := cs.options.StartAfter
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if resumeToken == nil {
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resumeToken = cs.options.ResumeAfter
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}
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var marshaledToken bson.Raw
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if resumeToken != nil {
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if marshaledToken, cs.err = bson.Marshal(resumeToken); cs.err != nil {
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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}
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cs.resumeToken = marshaledToken
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if cs.err = cs.buildPipelineSlice(pipeline); cs.err != nil {
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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var pipelineArr bsoncore.Document
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pipelineArr, cs.err = cs.pipelineToBSON()
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cs.aggregate.Pipeline(pipelineArr)
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if cs.err = cs.executeOperation(ctx, false); cs.err != nil {
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closeImplicitSession(cs.sess)
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return nil, cs.Err()
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}
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return cs, cs.Err()
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}
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func (cs *ChangeStream) createOperationDeployment(server driver.Server, connection driver.Connection) driver.Deployment {
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return &changeStreamDeployment{
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topologyKind: cs.client.deployment.Kind(),
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server: server,
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conn: connection,
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}
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}
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func (cs *ChangeStream) executeOperation(ctx context.Context, resuming bool) error {
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var server driver.Server
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var conn driver.Connection
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var err error
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if server, cs.err = cs.client.deployment.SelectServer(ctx, cs.selector); cs.err != nil {
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return cs.Err()
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}
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if conn, cs.err = server.Connection(ctx); cs.err != nil {
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return cs.Err()
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}
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defer conn.Close()
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cs.wireVersion = conn.Description().WireVersion
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cs.aggregate.Deployment(cs.createOperationDeployment(server, conn))
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if resuming {
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cs.replaceOptions(cs.wireVersion)
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csOptDoc, err := cs.createPipelineOptionsDoc()
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if err != nil {
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return err
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}
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pipIdx, pipDoc := bsoncore.AppendDocumentStart(nil)
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pipDoc = bsoncore.AppendDocumentElement(pipDoc, "$changeStream", csOptDoc)
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if pipDoc, cs.err = bsoncore.AppendDocumentEnd(pipDoc, pipIdx); cs.err != nil {
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return cs.Err()
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}
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cs.pipelineSlice[0] = pipDoc
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var plArr bsoncore.Document
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if plArr, cs.err = cs.pipelineToBSON(); cs.err != nil {
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return cs.Err()
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}
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cs.aggregate.Pipeline(plArr)
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}
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// If no deadline is set on the passed-in context, cs.client.timeout is set, and context is not already
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// a Timeout context, honor cs.client.timeout in new Timeout context for change stream operation execution
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// and potential retry.
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if _, deadlineSet := ctx.Deadline(); !deadlineSet && cs.client.timeout != nil && !internal.IsTimeoutContext(ctx) {
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newCtx, cancelFunc := internal.MakeTimeoutContext(ctx, *cs.client.timeout)
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// Redefine ctx to be the new timeout-derived context.
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ctx = newCtx
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// Cancel the timeout-derived context at the end of executeOperation to avoid a context leak.
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defer cancelFunc()
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}
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if original := cs.aggregate.Execute(ctx); original != nil {
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retryableRead := cs.client.retryReads && cs.wireVersion != nil && cs.wireVersion.Max >= 6
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if !retryableRead {
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cs.err = replaceErrors(original)
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return cs.err
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}
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cs.err = original
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switch tt := original.(type) {
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case driver.Error:
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if !tt.RetryableRead() {
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break
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}
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server, err = cs.client.deployment.SelectServer(ctx, cs.selector)
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if err != nil {
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break
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}
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conn.Close()
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conn, err = server.Connection(ctx)
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if err != nil {
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break
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}
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defer conn.Close()
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cs.wireVersion = conn.Description().WireVersion
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if cs.wireVersion == nil || cs.wireVersion.Max < 6 {
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break
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}
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cs.aggregate.Deployment(cs.createOperationDeployment(server, conn))
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cs.err = cs.aggregate.Execute(ctx)
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}
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if cs.err != nil {
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cs.err = replaceErrors(cs.err)
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return cs.Err()
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}
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}
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cs.err = nil
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cr := cs.aggregate.ResultCursorResponse()
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cr.Server = server
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cs.cursor, cs.err = driver.NewBatchCursor(cr, cs.sess, cs.client.clock, cs.cursorOptions)
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if cs.err = replaceErrors(cs.err); cs.err != nil {
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return cs.Err()
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}
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cs.updatePbrtFromCommand()
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if cs.options.StartAtOperationTime == nil && cs.options.ResumeAfter == nil &&
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cs.options.StartAfter == nil && cs.wireVersion.Max >= 7 &&
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cs.emptyBatch() && cs.resumeToken == nil {
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cs.operationTime = cs.sess.OperationTime
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}
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return cs.Err()
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}
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// Updates the post batch resume token after a successful aggregate or getMore operation.
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func (cs *ChangeStream) updatePbrtFromCommand() {
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// Only cache the pbrt if an empty batch was returned and a pbrt was included
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if pbrt := cs.cursor.PostBatchResumeToken(); cs.emptyBatch() && pbrt != nil {
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cs.resumeToken = bson.Raw(pbrt)
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}
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}
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func (cs *ChangeStream) storeResumeToken() error {
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// If cs.Current is the last document in the batch and a pbrt is included, cache the pbrt
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// Otherwise, cache the _id of the document
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var tokenDoc bson.Raw
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if len(cs.batch) == 0 {
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if pbrt := cs.cursor.PostBatchResumeToken(); pbrt != nil {
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tokenDoc = bson.Raw(pbrt)
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}
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}
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if tokenDoc == nil {
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var ok bool
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tokenDoc, ok = cs.Current.Lookup("_id").DocumentOK()
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if !ok {
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_ = cs.Close(context.Background())
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return ErrMissingResumeToken
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}
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}
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cs.resumeToken = tokenDoc
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return nil
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}
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func (cs *ChangeStream) buildPipelineSlice(pipeline interface{}) error {
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val := reflect.ValueOf(pipeline)
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if !val.IsValid() || !(val.Kind() == reflect.Slice) {
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cs.err = errors.New("can only transform slices and arrays into aggregation pipelines, but got invalid")
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return cs.err
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}
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cs.pipelineSlice = make([]bsoncore.Document, 0, val.Len()+1)
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csIdx, csDoc := bsoncore.AppendDocumentStart(nil)
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csDocTemp, err := cs.createPipelineOptionsDoc()
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if err != nil {
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return err
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}
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csDoc = bsoncore.AppendDocumentElement(csDoc, "$changeStream", csDocTemp)
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csDoc, cs.err = bsoncore.AppendDocumentEnd(csDoc, csIdx)
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if cs.err != nil {
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return cs.err
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}
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cs.pipelineSlice = append(cs.pipelineSlice, csDoc)
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for i := 0; i < val.Len(); i++ {
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var elem []byte
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elem, cs.err = transformBsoncoreDocument(cs.registry, val.Index(i).Interface(), true, fmt.Sprintf("pipeline stage :%v", i))
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if cs.err != nil {
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return cs.err
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}
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cs.pipelineSlice = append(cs.pipelineSlice, elem)
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}
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return cs.err
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}
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func (cs *ChangeStream) createPipelineOptionsDoc() (bsoncore.Document, error) {
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plDocIdx, plDoc := bsoncore.AppendDocumentStart(nil)
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if cs.streamType == ClientStream {
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plDoc = bsoncore.AppendBooleanElement(plDoc, "allChangesForCluster", true)
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}
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if cs.options.FullDocument != nil {
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// Only append a default "fullDocument" field if wire version is less than 6 (3.6). Otherwise,
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// the server will assume users want the default behavior, and "fullDocument" does not need to be
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// specified.
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if *cs.options.FullDocument != options.Default || (cs.wireVersion != nil && cs.wireVersion.Max < 6) {
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plDoc = bsoncore.AppendStringElement(plDoc, "fullDocument", string(*cs.options.FullDocument))
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}
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}
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if cs.options.FullDocumentBeforeChange != nil {
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plDoc = bsoncore.AppendStringElement(plDoc, "fullDocumentBeforeChange", string(*cs.options.FullDocumentBeforeChange))
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}
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if cs.options.ResumeAfter != nil {
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var raDoc bsoncore.Document
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raDoc, cs.err = transformBsoncoreDocument(cs.registry, cs.options.ResumeAfter, true, "resumeAfter")
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if cs.err != nil {
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return nil, cs.err
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}
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plDoc = bsoncore.AppendDocumentElement(plDoc, "resumeAfter", raDoc)
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}
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if cs.options.ShowExpandedEvents != nil {
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plDoc = bsoncore.AppendBooleanElement(plDoc, "showExpandedEvents", *cs.options.ShowExpandedEvents)
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}
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if cs.options.StartAfter != nil {
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var saDoc bsoncore.Document
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saDoc, cs.err = transformBsoncoreDocument(cs.registry, cs.options.StartAfter, true, "startAfter")
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if cs.err != nil {
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return nil, cs.err
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}
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plDoc = bsoncore.AppendDocumentElement(plDoc, "startAfter", saDoc)
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}
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if cs.options.StartAtOperationTime != nil {
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plDoc = bsoncore.AppendTimestampElement(plDoc, "startAtOperationTime", cs.options.StartAtOperationTime.T, cs.options.StartAtOperationTime.I)
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}
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// Append custom pipeline options.
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for optionName, optionValue := range cs.pipelineOptions {
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plDoc = bsoncore.AppendValueElement(plDoc, optionName, optionValue)
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}
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if plDoc, cs.err = bsoncore.AppendDocumentEnd(plDoc, plDocIdx); cs.err != nil {
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return nil, cs.err
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}
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return plDoc, nil
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}
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func (cs *ChangeStream) pipelineToBSON() (bsoncore.Document, error) {
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pipelineDocIdx, pipelineArr := bsoncore.AppendArrayStart(nil)
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for i, doc := range cs.pipelineSlice {
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pipelineArr = bsoncore.AppendDocumentElement(pipelineArr, strconv.Itoa(i), doc)
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}
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if pipelineArr, cs.err = bsoncore.AppendArrayEnd(pipelineArr, pipelineDocIdx); cs.err != nil {
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return nil, cs.err
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}
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return pipelineArr, cs.err
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}
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func (cs *ChangeStream) replaceOptions(wireVersion *description.VersionRange) {
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// Cached resume token: use the resume token as the resumeAfter option and set no other resume options
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if cs.resumeToken != nil {
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cs.options.SetResumeAfter(cs.resumeToken)
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cs.options.SetStartAfter(nil)
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cs.options.SetStartAtOperationTime(nil)
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return
|
|
}
|
|
|
|
// No cached resume token but cached operation time: use the operation time as the startAtOperationTime option and
|
|
// set no other resume options
|
|
if (cs.sess.OperationTime != nil || cs.options.StartAtOperationTime != nil) && wireVersion.Max >= 7 {
|
|
opTime := cs.options.StartAtOperationTime
|
|
if cs.operationTime != nil {
|
|
opTime = cs.sess.OperationTime
|
|
}
|
|
|
|
cs.options.SetStartAtOperationTime(opTime)
|
|
cs.options.SetResumeAfter(nil)
|
|
cs.options.SetStartAfter(nil)
|
|
return
|
|
}
|
|
|
|
// No cached resume token or operation time: set none of the resume options
|
|
cs.options.SetResumeAfter(nil)
|
|
cs.options.SetStartAfter(nil)
|
|
cs.options.SetStartAtOperationTime(nil)
|
|
}
|
|
|
|
// ID returns the ID for this change stream, or 0 if the cursor has been closed or exhausted.
|
|
func (cs *ChangeStream) ID() int64 {
|
|
if cs.cursor == nil {
|
|
return 0
|
|
}
|
|
return cs.cursor.ID()
|
|
}
|
|
|
|
// Decode will unmarshal the current event document into val and return any errors from the unmarshalling process
|
|
// without any modification. If val is nil or is a typed nil, an error will be returned.
|
|
func (cs *ChangeStream) Decode(val interface{}) error {
|
|
if cs.cursor == nil {
|
|
return ErrNilCursor
|
|
}
|
|
|
|
return bson.UnmarshalWithRegistry(cs.registry, cs.Current, val)
|
|
}
|
|
|
|
// Err returns the last error seen by the change stream, or nil if no errors has occurred.
|
|
func (cs *ChangeStream) Err() error {
|
|
if cs.err != nil {
|
|
return replaceErrors(cs.err)
|
|
}
|
|
if cs.cursor == nil {
|
|
return nil
|
|
}
|
|
|
|
return replaceErrors(cs.cursor.Err())
|
|
}
|
|
|
|
// Close closes this change stream and the underlying cursor. Next and TryNext must not be called after Close has been
|
|
// called. Close is idempotent. After the first call, any subsequent calls will not change the state.
|
|
func (cs *ChangeStream) Close(ctx context.Context) error {
|
|
if ctx == nil {
|
|
ctx = context.Background()
|
|
}
|
|
|
|
defer closeImplicitSession(cs.sess)
|
|
|
|
if cs.cursor == nil {
|
|
return nil // cursor is already closed
|
|
}
|
|
|
|
cs.err = replaceErrors(cs.cursor.Close(ctx))
|
|
cs.cursor = nil
|
|
return cs.Err()
|
|
}
|
|
|
|
// ResumeToken returns the last cached resume token for this change stream, or nil if a resume token has not been
|
|
// stored.
|
|
func (cs *ChangeStream) ResumeToken() bson.Raw {
|
|
return cs.resumeToken
|
|
}
|
|
|
|
// Next gets the next event for this change stream. It returns true if there were no errors and the next event document
|
|
// is available.
|
|
//
|
|
// Next blocks until an event is available, an error occurs, or ctx expires. If ctx expires, the error
|
|
// will be set to ctx.Err(). In an error case, Next will return false.
|
|
//
|
|
// If Next returns false, subsequent calls will also return false.
|
|
func (cs *ChangeStream) Next(ctx context.Context) bool {
|
|
return cs.next(ctx, false)
|
|
}
|
|
|
|
// TryNext attempts to get the next event for this change stream. It returns true if there were no errors and the next
|
|
// event document is available.
|
|
//
|
|
// TryNext returns false if the change stream is closed by the server, an error occurs when getting changes from the
|
|
// server, the next change is not yet available, or ctx expires. If ctx expires, the error will be set to ctx.Err().
|
|
//
|
|
// If TryNext returns false and an error occurred or the change stream was closed
|
|
// (i.e. cs.Err() != nil || cs.ID() == 0), subsequent attempts will also return false. Otherwise, it is safe to call
|
|
// TryNext again until a change is available.
|
|
//
|
|
// This method requires driver version >= 1.2.0.
|
|
func (cs *ChangeStream) TryNext(ctx context.Context) bool {
|
|
return cs.next(ctx, true)
|
|
}
|
|
|
|
func (cs *ChangeStream) next(ctx context.Context, nonBlocking bool) bool {
|
|
// return false right away if the change stream has already errored or if cursor is closed.
|
|
if cs.err != nil {
|
|
return false
|
|
}
|
|
|
|
if ctx == nil {
|
|
ctx = context.Background()
|
|
}
|
|
|
|
if len(cs.batch) == 0 {
|
|
cs.loopNext(ctx, nonBlocking)
|
|
if cs.err != nil {
|
|
cs.err = replaceErrors(cs.err)
|
|
return false
|
|
}
|
|
if len(cs.batch) == 0 {
|
|
return false
|
|
}
|
|
}
|
|
|
|
// successfully got non-empty batch
|
|
cs.Current = bson.Raw(cs.batch[0])
|
|
cs.batch = cs.batch[1:]
|
|
if cs.err = cs.storeResumeToken(); cs.err != nil {
|
|
return false
|
|
}
|
|
return true
|
|
}
|
|
|
|
func (cs *ChangeStream) loopNext(ctx context.Context, nonBlocking bool) {
|
|
for {
|
|
if cs.cursor == nil {
|
|
return
|
|
}
|
|
|
|
if cs.cursor.Next(ctx) {
|
|
// non-empty batch returned
|
|
cs.batch, cs.err = cs.cursor.Batch().Documents()
|
|
return
|
|
}
|
|
|
|
cs.err = replaceErrors(cs.cursor.Err())
|
|
if cs.err == nil {
|
|
// Check if cursor is alive
|
|
if cs.ID() == 0 {
|
|
return
|
|
}
|
|
|
|
// If a getMore was done but the batch was empty, the batch cursor will return false with no error.
|
|
// Update the tracked resume token to catch the post batch resume token from the server response.
|
|
cs.updatePbrtFromCommand()
|
|
if nonBlocking {
|
|
// stop after a successful getMore, even though the batch was empty
|
|
return
|
|
}
|
|
continue // loop getMore until a non-empty batch is returned or an error occurs
|
|
}
|
|
|
|
if !cs.isResumableError() {
|
|
return
|
|
}
|
|
|
|
// ignore error from cursor close because if the cursor is deleted or errors we tried to close it and will remake and try to get next batch
|
|
_ = cs.cursor.Close(ctx)
|
|
if cs.err = cs.executeOperation(ctx, true); cs.err != nil {
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (cs *ChangeStream) isResumableError() bool {
|
|
commandErr, ok := cs.err.(CommandError)
|
|
if !ok || commandErr.HasErrorLabel(networkErrorLabel) {
|
|
// All non-server errors or network errors are resumable.
|
|
return true
|
|
}
|
|
|
|
if commandErr.Code == errorCursorNotFound {
|
|
return true
|
|
}
|
|
|
|
// For wire versions 9 and above, a server error is resumable if it has the ResumableChangeStreamError label.
|
|
if cs.wireVersion != nil && cs.wireVersion.Includes(minResumableLabelWireVersion) {
|
|
return commandErr.HasErrorLabel(resumableErrorLabel)
|
|
}
|
|
|
|
// For wire versions below 9, a server error is resumable if its code is on the allowlist.
|
|
_, resumable := resumableChangeStreamErrors[commandErr.Code]
|
|
return resumable
|
|
}
|
|
|
|
// Returns true if the underlying cursor's batch is empty
|
|
func (cs *ChangeStream) emptyBatch() bool {
|
|
return cs.cursor.Batch().Empty()
|
|
}
|
|
|
|
// StreamType represents the cluster type against which a ChangeStream was created.
|
|
type StreamType uint8
|
|
|
|
// These constants represent valid change stream types. A change stream can be initialized over a collection, all
|
|
// collections in a database, or over a cluster.
|
|
const (
|
|
CollectionStream StreamType = iota
|
|
DatabaseStream
|
|
ClientStream
|
|
)
|