Need access to other docker container when probing

[MrMaxxan]

The docker image I try to slim down contains a service that will try to connect to postgres, kafka etc at startup. If I run the service locally I have postgres and kafka as docker images running locally. Now when I try to slim down the docker container it also needs to connect to these other postgres/kafka containers to be able to start before it's possible to probe the service.

I've tried different combinations with --expose, --publish-port, --new-expose etc, but it doesn't seem to work.

./slim build --show-clogs=true --expose 8088 --http-probe-cmd /actuator/health/readiness --target my-container:1.0.0 --tag mycontainer:slim --publish-port 5432
But the log from the service in my-container say Connection to localhost:5432 refused

So if my-container needs to connect to port 5432 on the host. Is that possible? Which of all parameters should be used for that?

If I would just run my docker container, then something like this works to connect to the correct ports: docker run --network host my-container:1.0.0 so then I tried something like:
./slim build --show-clogs=true --http-probe-cmd /actuator/health/readiness --target my-container:1.0.0 --tag mycontainer:slim --http-probe-ports 8088 --network=host but still not working. Then I get this log:

cmd=build info=container ip='127.0.0.1' message='obtained IP address'
time="2025-03-18T12:42:12+01:00" level=error msg="channel.NewCommandClient: NewClient error = wait timeout"
time="2025-03-18T12:42:12+01:00" level=error msg="ipc.NewClient init error = wait timeout"
slim: container stdout:
slim: container stderr:
slim: end of container logs =============
slim: container stdout:
slim: container stderr:
slim: end of container logs =============
cmd=build info=container status='crashed' id='2de68bf7252e4128b498da44557b68ab690a36cb07ee792ff7a25363d255a454' exit.code='2'
cmd=build state=exited code=-999 version=linux/amd64|Transformer|1.40.11|1b271555882eacdfb4e6598d6d0552e9b9b1449b|2024-02-02_01:36:22PM location.exe=/home/marcus/slimtoolkit/dist_linux location.sensor=/home/marcus/slimtoolkit/dist_linux/slim-sensor sensor.filemode=-rwxr-xr-x sensor.volume=slim-sensor.1.40.11-6-g965a82ed

[kcq]

@MrMaxxan there are a few options depending on the actual environment setup and how the other services need to run...

You said, If I run the service locally I have postgres and kafka as docker images running locally. If it's the case then you need to specify the network to use to talk to your postgres and kafka containers. This is done using the --network flag. You can setup the networks explicitly or if you use docker-compose then you can rely on the networks it creates. Here's a slimming example project where it's using the --network flag and docker-compose is used to run a Redis server, which the app container needs to reach: https://github.com/mintoolkit/examples/tree/master/node_compose

There's an easier way if you are using docker-compose instead of relying on the --network flag to connect to the network where your servers are running. You can use the --compose-file flag to point to your docker-compose yaml file where you app and your servers are declared as services. Then you point to the compose service for your application container image with the --target-compose-svc flag. Here's an example that uses the --compose-file and --target-compose-svc flags: https://github.com/mintoolkit/examples/tree/master/node_redis_compose