| // Copyright 2016 Google Inc. All Rights Reserved. |
| // |
| // 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 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| package pubsub |
| |
| import ( |
| "time" |
| |
| "github.com/golang/protobuf/ptypes" |
| pb "google.golang.org/genproto/googleapis/pubsub/v1" |
| ) |
| |
| // Message represents a Pub/Sub message. |
| type Message struct { |
| // ID identifies this message. |
| // This ID is assigned by the server and is populated for Messages obtained from a subscription. |
| // This field is read-only. |
| ID string |
| |
| // Data is the actual data in the message. |
| Data []byte |
| |
| // Attributes represents the key-value pairs the current message |
| // is labelled with. |
| Attributes map[string]string |
| |
| // ackID is the identifier to acknowledge this message. |
| ackID string |
| |
| // The time at which the message was published. |
| // This is populated by the server for Messages obtained from a subscription. |
| // This field is read-only. |
| PublishTime time.Time |
| |
| // size is the approximate size of the message's data and attributes. |
| size int |
| |
| calledDone bool |
| |
| // The done method of the iterator that created this Message. |
| doneFunc func(string, bool) |
| } |
| |
| func toMessage(resp *pb.ReceivedMessage) (*Message, error) { |
| if resp.Message == nil { |
| return &Message{ackID: resp.AckId}, nil |
| } |
| |
| pubTime, err := ptypes.Timestamp(resp.Message.PublishTime) |
| if err != nil { |
| return nil, err |
| } |
| return &Message{ |
| ackID: resp.AckId, |
| Data: resp.Message.Data, |
| Attributes: resp.Message.Attributes, |
| ID: resp.Message.MessageId, |
| PublishTime: pubTime, |
| }, nil |
| } |
| |
| // Ack indicates successful processing of a Message passed to the Subscriber.Receive callback. |
| // It should not be called on any other Message value. |
| // If message acknowledgement fails, the Message will be redelivered. |
| // Client code must call Ack or Nack when finished for each received Message. |
| // Calls to Ack or Nack have no effect after the first call. |
| func (m *Message) Ack() { |
| m.done(true) |
| } |
| |
| // Nack indicates that the client will not or cannot process a Message passed to the Subscriber.Receive callback. |
| // It should not be called on any other Message value. |
| // Nack will result in the Message being redelivered more quickly than if it were allowed to expire. |
| // Client code must call Ack or Nack when finished for each received Message. |
| // Calls to Ack or Nack have no effect after the first call. |
| func (m *Message) Nack() { |
| m.done(false) |
| } |
| |
| func (m *Message) done(ack bool) { |
| if m.calledDone { |
| return |
| } |
| m.calledDone = true |
| m.doneFunc(m.ackID, ack) |
| } |