mirror of https://github.com/tidwall/tile38.git
121 lines
3.8 KiB
Go
121 lines
3.8 KiB
Go
// Copyright 2016 Google LLC
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package pubsub
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import (
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"time"
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"github.com/golang/protobuf/ptypes"
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pb "google.golang.org/genproto/googleapis/pubsub/v1"
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)
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// Message represents a Pub/Sub message.
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type Message struct {
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// ID identifies this message.
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// This ID is assigned by the server and is populated for Messages obtained from a subscription.
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// This field is read-only.
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ID string
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// Data is the actual data in the message.
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Data []byte
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// Attributes represents the key-value pairs the current message
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// is labelled with.
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Attributes map[string]string
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// ackID is the identifier to acknowledge this message.
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ackID string
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// The time at which the message was published.
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// This is populated by the server for Messages obtained from a subscription.
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// This field is read-only.
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PublishTime time.Time
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// receiveTime is the time the message was received by the client.
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receiveTime time.Time
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// DeliveryAttempt is the number of times a message has been delivered.
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// This is part of the dead lettering feature that forwards messages that
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// fail to be processed (from nack/ack deadline timeout) to a dead letter topic.
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// If dead lettering is enabled, this will be set on all attempts, starting
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// with value 1. Otherwise, the value will be nil.
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// This field is read-only.
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//
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// It is EXPERIMENTAL and a part of a closed alpha that may not be
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// accessible to all users. This field is subject to change or removal
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// without notice.
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DeliveryAttempt *int
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// size is the approximate size of the message's data and attributes.
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size int
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calledDone bool
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// The done method of the iterator that created this Message.
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doneFunc func(string, bool, time.Time)
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}
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func toMessage(resp *pb.ReceivedMessage) (*Message, error) {
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if resp.Message == nil {
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return &Message{ackID: resp.AckId}, nil
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}
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pubTime, err := ptypes.Timestamp(resp.Message.PublishTime)
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if err != nil {
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return nil, err
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}
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var deliveryAttempt *int
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if resp.DeliveryAttempt > 0 {
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da := int(resp.DeliveryAttempt)
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deliveryAttempt = &da
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}
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return &Message{
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ackID: resp.AckId,
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Data: resp.Message.Data,
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Attributes: resp.Message.Attributes,
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ID: resp.Message.MessageId,
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PublishTime: pubTime,
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DeliveryAttempt: deliveryAttempt,
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}, nil
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}
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// Ack indicates successful processing of a Message passed to the Subscriber.Receive callback.
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// It should not be called on any other Message value.
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// If message acknowledgement fails, the Message will be redelivered.
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// Client code must call Ack or Nack when finished for each received Message.
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// Calls to Ack or Nack have no effect after the first call.
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func (m *Message) Ack() {
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m.done(true)
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}
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// Nack indicates that the client will not or cannot process a Message passed to the Subscriber.Receive callback.
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// It should not be called on any other Message value.
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// Nack will result in the Message being redelivered more quickly than if it were allowed to expire.
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// Client code must call Ack or Nack when finished for each received Message.
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// Calls to Ack or Nack have no effect after the first call.
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func (m *Message) Nack() {
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m.done(false)
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}
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func (m *Message) done(ack bool) {
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if m.calledDone {
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return
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}
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m.calledDone = true
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m.doneFunc(m.ackID, ack, m.receiveTime)
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}
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