[docker-compose] How to pass arguments to entrypoint in docker-compose.yml

I use this image: dperson/samba

The image is defining it's own entrypoint and I do not want to override it.

I need to pass arguments to the entrypoint, easy with docker only:

docker run ... dperson/samba arg1 arg2 arg3

But how to do it with docker_compose.yml ?

Right now I use as a workaround:

command: samba.sh arg1 arg2 arg3

But it is not satisfying as I force the redefinition of the entrypoint.

Whatever is specified in the command in docker-compose.yml should get appended to the entrypoint defined in the Dockerfile, provided entrypoint is defined in exec form in the Dockerfile.

If the EntryPoint is defined in shell form, then any CMD arguments will be ignored.

I was facing the same issue with jenkins ssh slave 'jenkinsci/ssh-slave'. However, my case was a bit complicated because it was necessary to pass an argument which contained spaces. I've managed to do it like below (entrypoint in dockerfile is in exec form):

command: ["some argument with space which should be treated as one"]

To override the default entrypoint, use entrypoint option. To pass the arguments use command.

Here is the example of replacing bash with sh in ubuntu image:

version: '3'
services:
  sh:
    entrypoint: /bin/sh
    command: -c "ps $$(echo $$$$)"
    image: ubuntu
    tty: true
  bash:
    entrypoint: /bin/bash
    command: -c "ps $$(echo $$$$)"
    image: ubuntu
    tty: true

Here is the output:

$ docker-compose up   
Starting test_sh_1                ... done
Starting 020211508a29_test_bash_1 ... done
Attaching to test_sh_1, 020211508a29_test_bash_1
sh_1    |   PID TTY      STAT   TIME COMMAND
sh_1    |     1 pts/0    Ss+    0:00 /bin/sh -c ps $(echo $$)
020211508a29_test_bash_1 |   PID TTY      STAT   TIME COMMAND
020211508a29_test_bash_1 |     1 pts/0    Rs+    0:00 ps 1

You can use docker-compose run instead of docker-compose up and tack the arguments on the end. For example:

docker-compose run dperson/samba arg1 arg2 arg3

If you need to connect to other docker containers, use can use --service-ports option:

docker-compose run --service-ports dperson/samba arg1 arg2 arg3

The command clause does work as @Karthik says above.

As a simple example, the following service will have a -inMemory added to its ENTRYPOINT when docker-compose up is run.

version: '2'
services:
  local-dynamo:
    build: local-dynamo
    image: spud/dynamo
    command: -inMemory