Question

previous thread的发展发现，提出问题时的假设是不合时宜的（子流程实际上并没有引起问题），因此我将重点放在帖子上。

我的错误消息：

找不到记录器的处理程序 “ google.cloud.pubsub_v1.subscriber._protocol.streaming_pull_manager”

我的意图：

将Google PubSub消息属性作为Python变量传递，以在以后的代码中重复使用。

我的代码：

import time
import logging

from google.cloud import pubsub_v1

project_id = "redacted"
subscription_name = "redacted"

def receive_messages_with_custom_attributes(project_id, subscription_name):
    """Receives messages from a pull subscription."""
    # [START pubsub_subscriber_sync_pull_custom_attributes]

    subscriber = pubsub_v1.SubscriberClient()
    subscription_path = subscriber.subscription_path(
        project_id, subscription_name)

    def callback(message):
        print('Received message: {}'.format(message.data))
        if message.attributes:
            #print('Attributes:')
            for key in message.attributes:
                value = message.attributes.get(key);
                #commented out to not print to terminal
                #which should not be necessary
                #print('{}: {}'.format(key, value))
        message.ack()

        print("this is before variables")
        dirpath = "~/subfolder1/"
        print(dirpath)
        namepath = message.data["name"]
        print(namepath)
        fullpath = dirpath + namepath
        print(fullpath)
        print("this is after variables")


    subscriber.subscribe(subscription_path, callback=callback)
    # The subscriber is non-blocking, so we must keep the main thread from
    # exiting to allow it to process messages in the background.
    print('Listening for messages on {}'.format(subscription_path))
    while True:
        time.sleep(60)
    # [END pubsub_subscriber_sync_pull_custom_attributes]

receive_messages_with_custom_attributes(project_id, subscription_name)

运行上述代码的完整控制台输出：

Listening for messages on projects/[redacted]
Received message: {
  "kind": "storage#object",
  "id": "[redacted]/0.testing/1548033442364022",
  "selfLink": "https://www.googleapis.com/storage/v1/b/[redacted]/o/BSD%2F0.testing",
  "name": "BSD/0.testing",
  "bucket": "[redacted]",
  "generation": "1548033442364022",
  "metageneration": "1",
  "contentType": "application/octet-stream",
  "timeCreated": "2019-01-21T01:17:22.363Z",
  "updated": "2019-01-21T01:17:22.363Z",
  "storageClass": "MULTI_REGIONAL",
  "timeStorageClassUpdated": "2019-01-21T01:17:22.363Z",
  "size": "0",
  "md5Hash": "1B2M2Y8AsgTpgAmY7PhCfg==",
  "mediaLink": "https://www.googleapis.com/download/storage/v1/b/[redacted]/o/BSD%2F0.testing?generation=1548033442364022&alt=media",
  "crc32c": "AAAAAA==",
  "etag": "CPb0uvvZ/d8CEAE="
}

this is before variables
/home/[redacted]
No handlers could be found for logger "google.cloud.pubsub_v1.subscriber._protocol.streaming_pull_manager"

如您所见，第一个字符串和string-defined-as-variable已打印出来，但是在尝试从刚刚生成的字典中定义变量时，代码中断了，并且没有再执行任何print()了。

Potentially related thread，那个用户正在发布cron作业，并从crontab envpaths找到了一个修复程序，但是我的情况是正在接收并且不使用任何cron作业，但是可能暗示在python后面/之内的另一层？ >

有人可以帮助我添加一个处理程序以使此代码按预期运行吗？

Answer 1

首先，如果我对您的输出显示内容有正确的了解，那么无论何时对Cloud Storage对象进行更改，您都在使用发布/订阅通知来发送消息。这些信息可能会有所帮助。

现在，message.data["name"]不起作用，因为message.data是BYTES object。因此，不能将其索引为字典。

要将其视为dict，首先必须将其解码为base64 （import base64）。之后，剩下的就是一个看起来像JSON格式的字符串。然后，您使用json.load() （不要忘记import json）将此字符串转换为字典。现在您可以为邮件编制索引了。

此代码为：

print("This is before variables")
dirpath = "/subfolder1/"
print(dirpath)

#Transform the bytes object into a string by decoding it
namepath = base64.b64decode(message.data).decode('utf-8')

#Transform the json formated string into a dict
namepath = json.loads(namepath)

print(namepath["name"])
fullpath = dirpath + namepath["name"]
print(fullpath)
print("this is after variables")

现在，如果您只想读取属性，则可以在顶部正确定义它们，例如：

    if message.attributes:
        print('Attributes:')
        for key in message.attributes:
            value = message.attributes.get(key)
            print('{}: {}'.format(key, value))

因此，您可以使用：

    print("this is before variables")
    dirpath = "~/subfolder1/"
    print(dirpath)
    namepath = message.attributes["objectId"]
    print(namepath)
    fullpath = dirpath + namepath
    print(fullpath)
    print("this is after variables")

请记住，在这种特殊情况下，"objectId"是文件名，因为它是来自发布/订阅的Cloud Storage通知使用的属性。如果您假装发送自定义消息，请将"objectId"更改为所需的属性名称。

Answer 2

正如Nahuel和Tripleee所解释的那样，问题在于消息是BYTES而不是字符串。但是，他们的代码不能完全正常工作，仍然抛出错误，我也不知道为什么。通过交叉引用google的pubsub appengine网站的示例代码，以及几个小时的反复试验，我发现以下代码可以正常工作。 可能不雅致和/或有不良做法，在这种情况下，请对其进行编辑并使其更可靠。

#Continues from after message.ack(), above code remains unchanged
#except needing to <import json>

    #this makes a message.data a true python dict with strings.
    payload = json.loads(message.data.decode('utf-8')) 

    #this finds the value of the dict with key "name"
    namepath = payload["name"]

    #this is just a static string to pre-pend to the file path
    dirpath = "/home/[redacted]/"

    #combine them into a single functioning path
    fullpath = dirpath + namepath

    #currently type 'unicode', so convert them to type 'str'
    fullpath = fullpath.encode("utf-8")

最后，我们将得到一个全路径，其纯类型为'str'，供以后的函数/命令使用。

如何为Google Cloud Pubsub“创建” /“分配”日志处理程序？

2 个答案: