How can I connect to the IB Gateway with ib_async running in a docker container?

[dekaidekai]

Hello thanks for the awesome tool!

I am running my ib_async python code in a docker container and trying to connect it to my IB Gateway app, but I am having some trouble and feel like I'm missing something in the setup.

Does anyone have any guidance on how to connect to the IB Gateway through ib_async code that is running in a docker container?

I am facing this issue when trying to connect to the IB Gateway app which is directly running on my host machine (Mac OS) or even when it's in another docker container using ib-gateway and connecting through the docker network. To try to simplify my issue though, below I'll explain the issue only when running IB Gateway app on my host machine.

Any help would be much appreciated, thank you!

Issue

(see below for my minimal reproducible set up)

It seems that my from inside the docker container it can find the IB Gateway port 4002 open using nc command. The function ib_async.connect will also connect successfully to the IB Gateway socket. However, if I'm not mistaken, after this I am thinking that ib_async will hang and never receive any data from the socket and therefore not complete the API connection and timeout at the await asyncio.wait_for(self.apiStart, timeout) part.

basic.py logs

Waiting for IB Gateway API on host.docker.internal:4002 ...
IB Gateway is up on host.docker.internal:4002...
Booting python app...

2025-09-17 22:25:04,724 asyncio DEBUG Using selector: EpollSelector
2025-09-17 22:25:04,724 ib_async.client INFO Connecting to host.docker.internal:4002 with clientId 1...
2025-09-17 22:25:04,729 ib_async.client INFO Connected
2025-09-17 22:25:34,764 ib_async.client INFO Disconnecting
2025-09-17 22:25:34,765 ib_async.client ERROR API connection failed: TimeoutError()
2025-09-17 22:25:34,765 ib_async.client INFO Disconnected.
...
File "/usr/local/lib/python3.11/asyncio/base_events.py", line 654, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.11/site-packages/ib_async/ib.py", line 2043, in connectAsync
await self.client.connectAsync(host, port, clientId, timeout)
File "/usr/local/lib/python3.11/site-packages/ib_async/client.py", line 228, in connectAsync
await asyncio.wait_for(self.apiStart, timeout)
File "/usr/local/lib/python3.11/asyncio/tasks.py", line 502, in wait_for
raise exceptions.TimeoutError() from exc
TimeoutError

However if I run the python code outside of the docker container and directly on my host machine, then the initial connection and API connection in ib_async quickly succeeds, and everything works as expected.

Minimal reproducible set up

• using Mac OS Docker Desktop to run python container
• using IB Gateway 10.39 directly on Mac

docker-compose.yml

services:
  basic:
    container_name: basic
    image: basic
    restart: unless-stopped
    network_mode: host
    environment:
      IB_HOST: host.docker.internal
      IB_PORT: 4002

Dockerfile for basic

FROM python:3.11

USER root

RUN apt-get update && \
    apt-get install -y --no-install-recommends netcat-traditional iputils-ping

# Environment: no .pyc files, unbuffered logs, and no pip cache
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1

##### Install python code
# copy local code to the container image.
RUN mkdir -p /home/basic
ENV APP_HOME=/home/basic
WORKDIR $APP_HOME
COPY basic.py ./src/basic.py

# install dependencies
RUN pip install ib_async

COPY ./entrypoint.sh /home/entrypoint.sh

##### Run
ENTRYPOINT ["/home/entrypoint.sh"]

entrypoint.sh

#!/bin/bash
set -euo pipefail

: "${IB_HOST:?IB_HOST must be set}"
: "${IB_PORT:?IB_PORT must be set}"

echo "Waiting for IB Gateway API on ${IB_HOST}:${IB_PORT} ..."
for i in $(seq 1 120); do
  if nc -z -w1 "$IB_HOST" "$IB_PORT" 2>/dev/null; then
    echo "IB Gateway is up on ${IB_HOST}:${IB_PORT}..."
    ##### start python #####
    echo "Booting python app..."
    exec python /home/basic/src/basic.py
  fi
  sleep 1
done

echo "ERROR: IB Gateway at ${IB_HOST}:${IB_PORT} is not open after 120s" >&2
exit 1

basic.py

import os
import logging
import time
from ib_async import IB, util


if __name__ == "__main__":
        ib = IB()
        util.logToConsole(level=logging.DEBUG)
        ib.connect(host=os.environ['IB_HOST'],
                   port=os.environ['IB_PORT'],
                   clientId=1,
                   timeout=30)
        print(ib.accountSummary())

        while True:
            time.sleep(10)

IB Gateway settings

• Read-Only API: OFF
• Socket port: 4002
• Master client ID:
• Allow connections from localhost only: OFF
  • Trusted IPs: