google-cloud-messaging - 谷歌云发布订阅数据丢失

Question

我遇到了 GCP pubsub 的问题，即在几秒钟内发布数千条消息时丢失了一小部分数据。

我正在记录两个 message_id来自 pubsub 和 session_id发布端和接收端的每条消息都是唯一的，我看到的结果是接收端的某些消息具有相同的 session_id ，但不同 message_id .此外，还丢失了一些消息。

例如，在一项测试中，我向 pubsub 发送了 5,000 条消息，并且恰好收到了 5,000 条消息，其中 8 条消息丢失。日志丢失消息如下所示:

MISSING sessionId:sessionId: 731 (missing in log from pull request, but present in log from Flask API)

messageId FOUND: messageId:108562396466545

API: 200 **** sessionId: 731, messageId:108562396466545 ******(Log from Flask API)

Pubsub: sessionId: 730, messageId:108562396466545(Log from pull request)

重复项看起来像:

======= Duplicates FOUND on sessionId: 730=======

sessionId: 730, messageId:108562396466545

sessionId: 730, messageId:108561339282318

(both are logs from pull request)

所有丢失的数据和重复项看起来像这样。

从上面的例子可以看出，有些消息已经取了 message_id的另一条消息，已经用两个不同的 message_id 发送了两次s。

我想知道是否有人能帮我弄清楚发生了什么？提前致谢。

代码

我有一个向 pubsub 发送消息的 API，如下所示:

from flask import Flask, request, jsonify, render_template
from flask_cors import CORS, cross_origin
import simplejson as json
from google.cloud import pubsub
from functools import wraps
import re
import json


app = Flask(__name__)
ps = pubsub.Client()

...

@app.route('/publish', methods=['POST'])
@cross_origin()
@json_validator
def publish_test_topic():
    pubsub_topic = 'test_topic'
    data = request.data

    topic = ps.topic(pubsub_topic)

    event = json.loads(data)

    messageId = topic.publish(data)
    return '200 **** sessionId: ' + str(event["sessionId"]) + ", messageId:" + messageId + " ******"

这是我用来从 pubsub 读取的代码:

从 google.cloud 导入 pubsub
进口重新
导入json

ps = pubsub.Client()
topic = ps.topic('test-xiu')
sub = topic.subscription('TEST-xiu')

max_messages = 1
stop = False

messages = []

class Message(object):
    """docstring for Message."""
    def __init__(self, sessionId, messageId):
        super(Message, self).__init__()
        self.seesionId = sessionId
        self.messageId = messageId


def pull_all():
    while stop == False:

        m = sub.pull(max_messages = max_messages, return_immediately = False)

        for data in m:
            ack_id = data[0]
            message = data[1]
            messageId = message.message_id
            data = message.data
            event = json.loads(data)
            sessionId = str(event["sessionId"])
            messages.append(Message(sessionId = sessionId, messageId = messageId))

            print '200 **** sessionId: ' + sessionId + ", messageId:" + messageId + " ******"

            sub.acknowledge(ack_ids = [ack_id])

pull_all()

为了生成 session_id，从 API 发送请求和记录响应:

// generate trackable sessionId
var sessionId = 0

var increment_session_id = function () {
  sessionId++;
  return sessionId;
}

var generate_data = function () {
  var data = {};
  // data.sessionId = faker.random.uuid();
  data.sessionId = increment_session_id();
  data.user = get_rand(userList);
  data.device = get_rand(deviceList);
  data.visitTime = new Date;
  data.location = get_rand(locationList);
  data.content = get_rand(contentList);

  return data;
}

var sendData = function (url, payload) {
  var request = $.ajax({
    url: url,
    contentType: 'application/json',
    method: 'POST',
    data: JSON.stringify(payload),
    error: function (xhr, status, errorThrown) {
      console.log(xhr, status, errorThrown);
      $('.result').prepend("<pre id='json'>" + JSON.stringify(xhr, null, 2) + "</pre>")
      $('.result').prepend("<div>errorThrown: " + errorThrown + "</div>")
      $('.result').prepend("<div>======FAIL=======</div><div>status: " + status + "</div>")
    }
  }).done(function (xhr) {
    console.log(xhr);
    $('.result').prepend("<div>======SUCCESS=======</div><pre id='json'>" + JSON.stringify(payload, null, 2) + "</pre>")
  })
}

$(submit_button).click(function () {
  var request_num = get_request_num();
  var request_url = get_url();
  for (var i = 0; i < request_num; i++) {
    var data = generate_data();
    var loadData = changeVerb(data, 'load');
    sendData(request_url, loadData);
  }
}) 

更新

我对 API 进行了更改，问题似乎消失了。我所做的更改不是使用一个 pubsub.Client()对于所有请求，我为每个传入的请求初始化了一个客户端。新的 API 如下所示:

from flask import Flask, request, jsonify, render_template
from flask_cors import CORS, cross_origin
import simplejson as json
from google.cloud import pubsub
from functools import wraps
import re
import json


app = Flask(__name__)

...

@app.route('/publish', methods=['POST'])
@cross_origin()
@json_validator
def publish_test_topic():

    ps = pubsub.Client()


    pubsub_topic = 'test_topic'
    data = request.data

    topic = ps.topic(pubsub_topic)

    event = json.loads(data)

    messageId = topic.publish(data)
    return '200 **** sessionId: ' + str(event["sessionId"]) + ", messageId:" + messageId + " ******"

Answer 1

与谷歌的一些人交谈过，这似乎是 Python 客户端的问题:

The consensus on our side is that there is a thread-safety problem in the current python client. The client library is being rewritten almost from scratch as we speak, so I don't want to pursue any fixes in the current version. We expect the new version to become available by end of June.

Running the current code with thread_safe: false in app.yaml or better yet just instantiating the client in every call should is the work around -- the solution you found.

详细解决方法请看 更新 在问题中