Question

每当客户端（即消费者）连接到我的Django服务器时，我都想在命令行中执行命令，然后打印该命令的返回代码：

from channels.generic.websocket import AsyncWebsocketConsumer
import asyncio

class Consumer(AsyncWebsocketConsumer):
    async def do_command(self):
        process = await asyncio.create_subprocess_shell('pwd', stdout=asyncio.subprocess.PIPE)
        try:
            line = await asyncio.wait_for(process.stdout.readline(), 5)
            print("line is" + line.decode())
            print(process.returncode)
            # wait for process to finish so we can check the return code
            await asyncio.wait_for(process.wait(), 5)
        except asyncio.TimeoutError:
            print("process timed out!")
        else:
            print("process finished successfully!")
        finally:
            print(process.returncode)

    async def connect(self):
        asyncio.get_event_loop().create_task(self.do_command())
        print("Finished scheduling do_command task")

运行上面的代码，我得到

Finished scheduling do_command task
line is /opt/working_dir/django
None
process timed out!
None

每当客户端连接到我的服务器时。

但是，process.returncode始终是None

那是为什么？我需要知道命令是否成功。

问题似乎专门与await process.wait有关。由于某些原因，该命令永远不会完成执行（即process.returncode始终为None）。

但是，以下代码可以正常工作：

import asyncio
async def do_command():
    process = await asyncio.create_subprocess_shell(cmd='pwd')
    await process.wait()
    print("Finished process.wait")
    print(process.returncode)

loop = asyncio.get_event_loop()
task = loop.create_task(do_command())
asyncio.get_event_loop().run_until_complete(task)
loop.close()
print("Finished Go Task")

返回：

/opt/working_dir/django
Finished process.wait
0
Finished Go Task

在Django频道中使用asyncio.create_subprocess_shell消费者

0 个答案: