[BUG] - Healthcheck fails when using proxy

[MatthiasJobst]

What docker image(s) are you using?

base-notebook

Host OS system and architecture running docker image

Windows 11 as host and linux/amd64 for docker

What Docker command are you running?

docker compose up with the following dockerfile:

version: '3.4'

services:
  datamining:
    container_name: xxxx
    image: xxxx
    build:
      context: .
      dockerfile: ./Dockerfile
    ports:
      - "8888:8888"
    volumes:
      - xxxx:/home/jovyan/work
    environment:
      - DOCKER_STACKS_JUPYTER_CMD=lab
    restart: on-failure

How to Reproduce the problem?

Precondition is that the machine has to operate in a corporate environment using the companies proxy.
Start the container as above.
Check the state of the container with docker container ls
The container is marked as unhealthy.

Command output

abcdefghijk    "tini -g -- start-no…"   x hours ago     Up x hours (unhealthy)        0.0.0.0:8888->8888/tcp                             xxxx

Expected behavior

abcdedfghi abcdefghijk "tini -g -- start-no…" x hours ago Up x hours (healthy) 0.0.0.0:8888->8888/tcp xxxx

Actual behavior

After investigating the issue the problem is that docker_healthcheck.py does not run successfully giving the following error message:

Traceback (most recent call last):
  File "/opt/conda/lib/python3.11/site-packages/urllib3/connectionpool.py", line 790, in urlopen
    response = self._make_request(
               ^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/urllib3/connectionpool.py", line 536, in _make_request
    response = conn.getresponse()
               ^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/urllib3/connection.py", line 461, in getresponse
    httplib_response = super().getresponse()
                       ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/http/client.py", line 1378, in getresponse
    response.begin()
  File "/opt/conda/lib/python3.11/http/client.py", line 318, in begin
    version, status, reason = self._read_status()
                              ^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/http/client.py", line 287, in _read_status
    raise RemoteDisconnected("Remote end closed connection without"
http.client.RemoteDisconnected: Remote end closed connection without response

The above exception was the direct cause of the following exception:

urllib3.exceptions.ProxyError: ('Unable to connect to proxy', RemoteDisconnected('Remote end closed connection without response'))

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/opt/conda/lib/python3.11/site-packages/requests/adapters.py", line 486, in send
    resp = conn.urlopen(
           ^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/urllib3/connectionpool.py", line 844, in urlopen
    retries = retries.increment(
              ^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/urllib3/util/retry.py", line 515, in increment
    raise MaxRetryError(_pool, url, reason) from reason  # type: ignore[arg-type]
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
urllib3.exceptions.MaxRetryError: HTTPConnectionPool(host='host.docker.internal', port=9000): Max retries exceeded with url: http://7702f0e1c7d4:8888/api (Caused by ProxyError('Unable to connect to proxy', RemoteDisconnected('Remote end closed connection without response')))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/etc/jupyter/docker_healthcheck.py", line 19, in <module>
    r = requests.get(url, verify=False)  # request without SSL verification
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/requests/api.py", line 73, in get
    return request("get", url, params=params, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/requests/api.py", line 59, in request
    return session.request(method=method, url=url, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/requests/sessions.py", line 589, in request
    resp = self.send(prep, **send_kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/requests/sessions.py", line 703, in send
    r = adapter.send(request, **kwargs)
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.11/site-packages/requests/adapters.py", line 513, in send
    raise ProxyError(e, request=request)
requests.exceptions.ProxyError: HTTPConnectionPool(host='host.docker.internal', port=9000): Max retries exceeded with url: http://7702f0e1c7d4:8888/api (Caused by ProxyError('Unable to connect to proxy', RemoteDisconnected('Remote end closed connection without response')))

Anything else?

After investigating the issue further I came to the conclusion that using the proxy will be the problem. So I applied the following fix to docker_healthcheck.py:

proxies = {
  "http": None,
  "https": None,
}

r = requests.get(url, proxies=proxies, verify=False)  # request without SSL verification

Now the healthcheck works!

Latest Docker version

• I've updated my Docker version to the latest available, and the issue still persists

[mathbunnyru]

@MatthiasJobst could you please send a PR to fix this?
If it's possible, please, also add a test, which works with your fix and doesn't work in current state.

[MatthiasJobst]

Yes, I will do. The change is fairly basic. But I am unexperienced using the test framework, such that I might not be able to comply with your request on including tests.
Nevertheless I will give it a try.