| // Copyright (C) MongoDB, Inc. 2017-present. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| // not use this file except in compliance with the License. You may obtain |
| // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| |
| package command |
| |
| import ( |
| "context" |
| |
| "github.com/mongodb/mongo-go-driver/bson" |
| "github.com/mongodb/mongo-go-driver/mongo/readconcern" |
| "github.com/mongodb/mongo-go-driver/mongo/readpref" |
| "github.com/mongodb/mongo-go-driver/mongo/writeconcern" |
| "github.com/mongodb/mongo-go-driver/x/bsonx" |
| "github.com/mongodb/mongo-go-driver/x/mongo/driver/session" |
| "github.com/mongodb/mongo-go-driver/x/network/description" |
| "github.com/mongodb/mongo-go-driver/x/network/wiremessage" |
| ) |
| |
| // Aggregate represents the aggregate command. |
| // |
| // The aggregate command performs an aggregation. |
| type Aggregate struct { |
| NS Namespace |
| Pipeline bsonx.Arr |
| CursorOpts []bsonx.Elem |
| Opts []bsonx.Elem |
| ReadPref *readpref.ReadPref |
| WriteConcern *writeconcern.WriteConcern |
| ReadConcern *readconcern.ReadConcern |
| Clock *session.ClusterClock |
| Session *session.Client |
| |
| result bson.Raw |
| err error |
| } |
| |
| // Encode will encode this command into a wire message for the given server description. |
| func (a *Aggregate) Encode(desc description.SelectedServer) (wiremessage.WireMessage, error) { |
| cmd, err := a.encode(desc) |
| if err != nil { |
| return nil, err |
| } |
| |
| return cmd.Encode(desc) |
| } |
| |
| func (a *Aggregate) encode(desc description.SelectedServer) (*Read, error) { |
| if err := a.NS.Validate(); err != nil { |
| return nil, err |
| } |
| |
| command := bsonx.Doc{ |
| {"aggregate", bsonx.String(a.NS.Collection)}, |
| {"pipeline", bsonx.Array(a.Pipeline)}, |
| } |
| |
| cursor := bsonx.Doc{} |
| hasOutStage := a.HasDollarOut() |
| |
| for _, opt := range a.Opts { |
| switch opt.Key { |
| case "batchSize": |
| if opt.Value.Int32() == 0 && hasOutStage { |
| continue |
| } |
| cursor = append(cursor, opt) |
| default: |
| command = append(command, opt) |
| } |
| } |
| command = append(command, bsonx.Elem{"cursor", bsonx.Document(cursor)}) |
| |
| // add write concern because it won't be added by the Read command's Encode() |
| if desc.WireVersion.Max >= 5 && hasOutStage && a.WriteConcern != nil { |
| t, data, err := a.WriteConcern.MarshalBSONValue() |
| if err != nil { |
| return nil, err |
| } |
| var xval bsonx.Val |
| err = xval.UnmarshalBSONValue(t, data) |
| if err != nil { |
| return nil, err |
| } |
| command = append(command, bsonx.Elem{Key: "writeConcern", Value: xval}) |
| } |
| |
| return &Read{ |
| DB: a.NS.DB, |
| Command: command, |
| ReadPref: a.ReadPref, |
| ReadConcern: a.ReadConcern, |
| Clock: a.Clock, |
| Session: a.Session, |
| }, nil |
| } |
| |
| // HasDollarOut returns true if the Pipeline field contains a $out stage. |
| func (a *Aggregate) HasDollarOut() bool { |
| if a.Pipeline == nil { |
| return false |
| } |
| if len(a.Pipeline) == 0 { |
| return false |
| } |
| |
| val := a.Pipeline[len(a.Pipeline)-1] |
| |
| doc, ok := val.DocumentOK() |
| if !ok || len(doc) != 1 { |
| return false |
| } |
| return doc[0].Key == "$out" |
| } |
| |
| // Decode will decode the wire message using the provided server description. Errors during decoding |
| // are deferred until either the Result or Err methods are called. |
| func (a *Aggregate) Decode(desc description.SelectedServer, wm wiremessage.WireMessage) *Aggregate { |
| rdr, err := (&Read{}).Decode(desc, wm).Result() |
| if err != nil { |
| a.err = err |
| return a |
| } |
| |
| return a.decode(desc, rdr) |
| } |
| |
| func (a *Aggregate) decode(desc description.SelectedServer, rdr bson.Raw) *Aggregate { |
| a.result = rdr |
| return a |
| } |
| |
| // Result returns the result of a decoded wire message and server description. |
| func (a *Aggregate) Result() (bson.Raw, error) { |
| if a.err != nil { |
| return nil, a.err |
| } |
| return a.result, nil |
| } |
| |
| // Err returns the error set on this command. |
| func (a *Aggregate) Err() error { return a.err } |
| |
| // RoundTrip handles the execution of this command using the provided wiremessage.ReadWriter. |
| func (a *Aggregate) RoundTrip(ctx context.Context, desc description.SelectedServer, rw wiremessage.ReadWriter) (bson.Raw, error) { |
| cmd, err := a.encode(desc) |
| if err != nil { |
| return nil, err |
| } |
| |
| rdr, err := cmd.RoundTrip(ctx, desc, rw) |
| if err != nil { |
| return nil, err |
| } |
| |
| return a.decode(desc, rdr).Result() |
| } |