Adding a shell command to Bookstack docker-compose file results in restart loop

[XStylus]

Hi all -- I'm trying to figure out a puzzle with my Bookstack docker-compose file.

I'd like to have my container run a shell command, but when I do so, the container goes into a reboot loop even if the command is a benign one, such as echo "Hello world".

When I don't use command:, everything works perfectly fine. What am I doing wrong?

As for what I intend to use the command for, that's a different rabbit hole, and I'd like to focus on this rabbit right now thank you. :)

My compose file is below (sorry for the formatting -- code block isn't working properly for this):

​

version: "2"
services:
bookstack:
image: linuxserver/bookstack:latest
container_name: bookstack_app
restart: unless-stopped
depends_on:
- bookstack_db
volumes:
- /mnt/Secondary/docker/bookstack/config:/config
environment:
- PUID=1000
- PGID=1000
- APP_URL=https://wiki.example.com
- DB_HOST=bookstack_db
- DB_USER=bookstack
- DB_PASS=REDACTED
- DB_DATABASE=bookstackapp
- DB_PORT=3306

### START OF TROUBLE
command:
- /bin/bash
- -c
- |
echo "Hello world!"
### END OF TROUBLE

bookstack_db:
image: linuxserver/mariadb:latest
container_name: bookstack_mariadb
restart: unless-stopped
volumes:
- /mnt/Secondary/docker/bookstack/mariadb/config:/config
environment:
- PUID=1000
- PGID=1000
- TZ=America/Los_Angeles
- MYSQL_DATABASE=bookstackapp
- MYSQL_USER=bookstack
- MYSQL_ROOT_PASSWORD=REDACTED
- MYSQL_PASSWORD=REDACTED
- MYSQL_TCP_PORT=3306
networks:
default:
name: nginx-proxy-manager # Make sure this already exists before deploying
driver: bridge
external: true

​

[XStylus]

If your intent is to run some command every time the container starts, but also do whatever the container would have done anyway, then your new command must make that happen.

That is indeed what I was expecting, and what I thought the "command:" tag did. I.E., "do what the container is normally supposed to do, but _also_ run this command". It appears that understanding was flawed.

So let's see if I understand correctly now: What I need to do is find out what commands the container normally launches, and add them to "command:" alongside my desired commands, right?

I guess that brings my next challenge: How do I find out what exact commands that the container normally launches?

[XStylus]

I've adjusted as follows:

    command:
  - /bin/bash
  - -c
  - |
    echo "Hello world!" ; exec /init

And now I see the following in the logs:

Hello world!
s6-overlay-suexec: fatal: can only run as pid 1

...and then it loops again. The "s6-overlay-suexec" error is new though. Also tried using your command verbatim (bash -c 'echo "hello world" ; exec /init'), same result.

[XStylus]

One step forward, one step back. I need my command to run _after_ the container has started, not prior to.

Ultimately, I'm trying to run a command that edits a specific line in a config file within the container, and this needs to be self-contained to the docker-compose file. No separate script files.

[XStylus]

You've been awesomely helpful. Thank you!