使用Azure Communication Email Python SDK异步发件报错求助

一、object NoneType can't be used in 'await' expression异常原因 #

你使用了Azure Communication Email的同步客户端EmailClient，它的begin_send()返回的是同步Poller对象，其wait()方法返回None，而你对None使用了await，因此抛出异常。

二、解决异常并实现真正异步发送的步骤 #

1. 替换为异步客户端AsyncEmailClient #

Azure SDK提供了异步版本的邮件客户端，解决同步Poller的await问题：

• 导入异步客户端：from azure.communication.aio.email import AsyncEmailClient
• 使用AsyncEmailClient.from_connection_string()创建客户端，并用异步上下文管理（async with）确保资源正确释放
• 异步客户端的begin_send()、poller.wait()、poller.result()均为可await方法，不会返回None

2. 修改后的核心代码 #

from azure.communication.aio.email import AsyncEmailClient
import os
import asyncio

class Email(Configuration):
    def __init__(self):
        super().__init__()
        self.logger_file = 'email_exception.log'

    async def send_mail(self, email_content: dict, email_recipient: str = None):
        print(f" sending email called")
        error = False
        message = "Success"
        recipient_address = email_recipient or os.getenv("RECIPIENT_EMAIL_ADDRESS")

        try:
            content = {
                "senderAddress": sender_address,
                "recipients":  {
                    "to": [{"address": recipient_address}, {"address": recipient_address}],
                    "cc": [{"address": recipient_address}],
                    "bcc": [{"address": recipient_address}]
                },
                "content": email_content
            }
            # 初始化异步客户端并通过async with管理
            async with AsyncEmailClient.from_connection_string(connection_string) as client:
                # 异步触发邮件发送
                poller = await client.begin_send(content)

                time_elapsed = 0
                while not poller.done():
                    await poller.wait(POLLER_WAIT_TIME)
                    time_elapsed += POLLER_WAIT_TIME

                    if time_elapsed > 18 * POLLER_WAIT_TIME:
                        raise RuntimeError("Polling timed out.")

                # 异步获取发送结果
                result = await poller.result()
                if result["status"] == "Succeeded":
                    print(f"Successfully sent the emails (operation id: {result['id']})")
                    return error, message
                else:
                    raise RuntimeError(str(result["error"]))

        except Exception as ex:
            self.logger.error(f"exception was thrown when sending email {str(ex)}")
            error = True
            message = str(ex)
            return error, message

3. 实现真正的异步调用 #

当前代码修改后，若直接调用await email.send_mail()仍会阻塞主流程。要实现非阻塞的异步发送，需将邮件任务提交到事件循环后台执行：

async def main():
    email = Email()
    email_content = {"subject": "Test", "plainText": "Hello"}
    # 提交后台任务，主流程无需等待发送完成
    asyncio.create_task(email.send_mail(email_content))
    # 执行其他业务逻辑...

asyncio.run(main())

关键注意点 #

• 异步客户端必须配合async with使用，避免资源泄漏
• 多次调用时，用asyncio.create_task可并行执行多个邮件发送任务，大幅提升效率
• 若需要监听发送结果，可通过asyncio.gather()或任务的result()方法获取，但需注意异常处理

内容的提问来源于stack exchange，提问作者ira