Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | // Copyright (C) MongoDB, Inc. 2017-present. |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); you may |
| 4 | // not use this file except in compliance with the License. You may obtain |
| 5 | // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 |
| 6 | |
| 7 | package command |
| 8 | |
| 9 | import ( |
| 10 | "context" |
| 11 | |
| 12 | "fmt" |
| 13 | |
| 14 | "github.com/mongodb/mongo-go-driver/bson" |
| 15 | "github.com/mongodb/mongo-go-driver/mongo/readpref" |
| 16 | "github.com/mongodb/mongo-go-driver/x/bsonx" |
| 17 | "github.com/mongodb/mongo-go-driver/x/mongo/driver/session" |
| 18 | "github.com/mongodb/mongo-go-driver/x/network/description" |
| 19 | "github.com/mongodb/mongo-go-driver/x/network/result" |
| 20 | "github.com/mongodb/mongo-go-driver/x/network/wiremessage" |
| 21 | ) |
| 22 | |
| 23 | // GetLastError represents the getLastError command. |
| 24 | // |
| 25 | // The getLastError command is used for getting the last |
| 26 | // error from the last command on a connection. |
| 27 | // |
| 28 | // Since GetLastError only makes sense in the context of |
| 29 | // a single connection, there is no Dispatch method. |
| 30 | type GetLastError struct { |
| 31 | Clock *session.ClusterClock |
| 32 | Session *session.Client |
| 33 | |
| 34 | err error |
| 35 | res result.GetLastError |
| 36 | } |
| 37 | |
| 38 | // Encode will encode this command into a wire message for the given server description. |
| 39 | func (gle *GetLastError) Encode() (wiremessage.WireMessage, error) { |
| 40 | encoded, err := gle.encode() |
| 41 | if err != nil { |
| 42 | return nil, err |
| 43 | } |
| 44 | return encoded.Encode(description.SelectedServer{}) |
| 45 | } |
| 46 | |
| 47 | func (gle *GetLastError) encode() (*Read, error) { |
| 48 | // This can probably just be a global variable that we reuse. |
| 49 | cmd := bsonx.Doc{{"getLastError", bsonx.Int32(1)}} |
| 50 | |
| 51 | return &Read{ |
| 52 | Clock: gle.Clock, |
| 53 | DB: "admin", |
| 54 | ReadPref: readpref.Secondary(), |
| 55 | Session: gle.Session, |
| 56 | Command: cmd, |
| 57 | }, nil |
| 58 | } |
| 59 | |
| 60 | // Decode will decode the wire message using the provided server description. Errors during decoding |
| 61 | // are deferred until either the Result or Err methods are called. |
| 62 | func (gle *GetLastError) Decode(wm wiremessage.WireMessage) *GetLastError { |
| 63 | reply, ok := wm.(wiremessage.Reply) |
| 64 | if !ok { |
| 65 | gle.err = fmt.Errorf("unsupported response wiremessage type %T", wm) |
| 66 | return gle |
| 67 | } |
| 68 | rdr, err := decodeCommandOpReply(reply) |
| 69 | if err != nil { |
| 70 | gle.err = err |
| 71 | return gle |
| 72 | } |
| 73 | return gle.decode(rdr) |
| 74 | } |
| 75 | |
| 76 | func (gle *GetLastError) decode(rdr bson.Raw) *GetLastError { |
| 77 | err := bson.Unmarshal(rdr, &gle.res) |
| 78 | if err != nil { |
| 79 | gle.err = err |
| 80 | return gle |
| 81 | } |
| 82 | |
| 83 | return gle |
| 84 | } |
| 85 | |
| 86 | // Result returns the result of a decoded wire message and server description. |
| 87 | func (gle *GetLastError) Result() (result.GetLastError, error) { |
| 88 | if gle.err != nil { |
| 89 | return result.GetLastError{}, gle.err |
| 90 | } |
| 91 | |
| 92 | return gle.res, nil |
| 93 | } |
| 94 | |
| 95 | // Err returns the error set on this command. |
| 96 | func (gle *GetLastError) Err() error { return gle.err } |
| 97 | |
| 98 | // RoundTrip handles the execution of this command using the provided wiremessage.ReadWriter. |
| 99 | func (gle *GetLastError) RoundTrip(ctx context.Context, rw wiremessage.ReadWriter) (result.GetLastError, error) { |
| 100 | cmd, err := gle.encode() |
| 101 | if err != nil { |
| 102 | return result.GetLastError{}, err |
| 103 | } |
| 104 | |
| 105 | rdr, err := cmd.RoundTrip(ctx, description.SelectedServer{}, rw) |
| 106 | if err != nil { |
| 107 | return result.GetLastError{}, err |
| 108 | } |
| 109 | |
| 110 | return gle.decode(rdr).Result() |
| 111 | } |