尝试使用python从azure函数触发url时，出现错误，提示“未使用$return绑定返回非None值”

Question

下面是代码，

import logging
import json 
import urllib.request
import urllib.parse
import azure.functions as func


def main(myblob: func.InputStream):
    logging.info(f"Python blob trigger function processed blob \n"
                 f"Name: {myblob.name}\n"
                 f"Blob Size: {myblob.length} bytes")
    response = urllib.request.urlopen("http://example.com:5000/processing")
    return {
        'statusCode': 200,
        'body': json.dumps(response.read().decode('utf-8'))
    }

错误：结果：失败异常：运行时错误：没有$return绑定的函数“abc”返回了一个非无值堆栈：文件“/azure functions host/workers/python/3.7/LINUX/X64/azure_functions_worker/dispatcher.py”，第341行，在_handle_调用_请求f'function{fi.name！r}中，没有$return绑定”。同样的代码也适用于lambda。。请帮助我调试azure函数。

function.json

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "myblob",
      "type": "blobTrigger",
      "direction": "in",
      "path": "sourcemetadata/{name}",
      "connection": "AzureWebJobsStorage"
    }
  ]
}

Answer 1

在Azure函数中，如果在函数app code中使用return，则表示要使用输出绑定。但是您没有在function.json中定义它。请定义它。有关更多详细信息，请参阅此处和此处

举个例子

我使用流程blob和blob触发器，并使用队列输出绑定将消息发送到azure队列

1. function.json

{
  "scriptFile": "__init__.py",
  "bindings": [
    {
      "name": "myblob",
      "type": "blobTrigger",
      "direction": "in",
      "path": "test/{name}.csv",
      "connection": "AzureWebJobsStorage"
    },
    {
      "name": "$return",
      "direction": "out",
      "type": "queue",
      "queueName": "outqueue",
      "connection": "AzureWebJobsStorage"
    }
  ]
}

async def main(myblob: func.InputStream) :
    
    logging.info(f"Python blob trigger function processed blob \n"
                 f"Name: {myblob.name}\n")
    return "OK"