httpx.ConnectError: All connection attempts failed

[cgs041328]

Dear all, I hope I find you good.

I'm facing a weird issue with the AsyncClient:

Platform

• docker, python:3.9-alpine3.13

version

• httpx==0.21.1

Code

client = httpx.AsyncClient()    
req = client.build_request("GET", url)    
r = await client.send(req, stream=True)    

Traceback

File "/code/./app/learning/api/api_file.py", line 105, in download
    r = await client.send(req, stream=True)
  File "/usr/local/lib/python3.9/site-packages/httpx/_client.py", line 1600, in send
    response = await self._send_handling_auth(
  File "/usr/local/lib/python3.9/site-packages/httpx/_client.py", line 1628, in _send_handling_auth
    response = await self._send_handling_redirects(
  File "/usr/local/lib/python3.9/site-packages/httpx/_client.py", line 1665, in _send_handling_redirects
    response = await self._send_single_request(request)
  File "/usr/local/lib/python3.9/site-packages/httpx/_client.py", line 1702, in _send_single_request
    response = await transport.handle_async_request(request)
  File "/usr/local/lib/python3.9/site-packages/httpx/_transports/default.py", line 291, in handle_async_request
    resp = await self._pool.handle_async_request(req)
  File "/usr/local/lib/python3.9/contextlib.py", line 137, in __exit__
    self.gen.throw(typ, value, traceback)
  File "/usr/local/lib/python3.9/site-packages/httpx/_transports/default.py", line 77, in map_httpcore_exceptions
    raise mapped_exc(message) from exc
httpx.ConnectError: All connection attempts failed

Best Regards,

[tomchristie]

So, it couldn't connect. Although the error messaging obviously isn't very helpful for you in determining why.

Take things step by step. First, simplify it right down...

import httpx

httpx.get(url)  # What does this result in?

Try a different library...

import requests

requests.get(url)  # How about now?

Try a different tool entirely...

Try a different library...

$ curl <url>  # This?

Also, is this a public URL that you can share, so others can help you more easily?

[cgs041328]

Thanks for replying, this is a private AWS S3 storage call, and error is not always happen, it only happens in one of the hundreds of concurrent calls, so wondering it's a client error or a server error.

[YuvalHad1220]

did you resolve the issue?

[akdev-tech]

The same errors when trying to make 15 concurrent calls from Docker running on AWS EC2 instance

[cgs041328]

@MilkaPeeka @akdev-tech , i resolved issue by upgrading anyio from 3.4.0 to 3.5.0

[akdev-tech]

Just made some tests. I meet the same problem when sharing httpx.AsyncClient() instance between coroutines. But when I changed my code to every coroutine using own httpx.AsyncClient() instance the problem has gone.

Before:

client = httpx.AsyncClient()

def coro():
    req = await client.post("<url>", json=data)

After:

def coro():
    async with httpx.AsyncClient() as client:
        req = await client.post("<url>", json=data)

[HMaker]

So httpx is not coroutine-safe?

[zanieb]

httpx is coroutine safe but your client context should span the lifetime of all the coroutines e.g.

do

async with httpx.AsyncClient(...) as client:
    async with anyio.create_task_group() as tg:
        tg.start_soon(client.post, ...)
        tg.start_soon(client.post, ...)

not

async with anyio.create_task_group() as tg:
    async with httpx.AsyncClient(...) as client:
        tg.start_soon(client.post, ...)
    tg.start_soon(client.post, ...)

If you have problems please provide a complete example. I'm not sure what @akdev-tech was doing but you should not need to context manage the client in every coroutine.