Can the Dockerfile be modified to use the PUID and GUID from compose.yaml environment?

[tonydiethelm]

Hi!

First.... Thanks for this! It's awesome! :D

Ok. Here's my problem: The containerized server is writing to the data folder as UID and GID 1000. But I don't use that account to do all my Minecraft stuff. I used UID/GUI 1002 (a user called "minecraft", see my compose.yaml file below). So all the files in the data folder are being set to a user I don't use, and I have to CHOWN the files all the time, which is annoying.

This is a normal Docker problem, usually we can get around it by setting a UID and GID to use in the compose.yaml file. Here's mine for reference...

container_name: minecraft.swampySavannah
tty: true
stdin_open: true
restart: always
environment:
  - PUID=1002
  - PGID=1002
  - TZ=Etc/UTC
ports:
  - "25567:25565"
environment:
  EULA: "TRUE"
  MOTD: "Diethelm Swampy Savannah, we're making a village!"
volumes:
  # attach the relative directory 'data' to the container's /data path
  - /home/minecraft/swampySavannah/data:/data

Setting the PUID and PGID in the environment key should, in theory, be used by the containerized process so it can run stuff and make files as that user/group.

But that's not happening, and I think it's because you're specifying pid/gid 1000 in the Dockerfile?

Line 67 in your Dockerfile...

ENV TYPE=VANILLA VERSION=LATEST EULA="" UID=1000 GID=1000 LC_ALL=en_US.UTF-8

It's not a BIG deal, but could you change it so your Thing respects the environment variables set in the compose.yaml file when it runs?

Sorry if I'm totally wrong here or way off base. Apologies for not digging in and submitting a pull request. I have kids. I'm tired... :D

Thanks again! Your server setup Thing is enabling me to play minecraft with my kiddos on our own server without random internet weirdos!

:D

Tony

[tonydiethelm]

And if this isn't important to you, just tell me. I'd be happy to dig in, fix this, and submit a pull request. I just figured you could do this about a zillion times faster than I could. :D

[itzg]

I'm a little confused why you're talking about PUID and PGID when the variables should be UID and GID:

https://docker-minecraft-server.readthedocs.io/en/latest/configuration/misc-options/#running-as-alternate-usergroup-id

Using the compose file:

services:
  mc:
    image: itzg/minecraft-server
    environment:
      EULA: true
      UID: 1002
      GID: 1002
    volumes:
      - data:/data
volumes:
  data:

The startup shows that it is accessing /data as uid 1002 (gid 1002):

[init] Changing uid of minecraft to 1002
[init] Changing gid of minecraft to 1002
[init] Running as uid=1002 gid=1002 with /data as 'drwxr-x--- 2 1002 1000 4096 Jan 13 02:57 /data'

It's not a BIG deal, but could you change it so your Thing respects the environment variables set in the compose.yaml file when it runs?

That's all in docker's hands and it does indeed do that already. The environment in the compose file (or -e args on docker run) most definitely override the ENV in the Dockerfile, which just serve as defaults.

[itzg]

FYI, that initial handling of UID and GID happens here:

docker-minecraft-server/scripts/start

Lines 16 to 51 in 4b24251

	if ! isTrue "${SKIP_SUDO:-false}" && [ "$(id -u)" = 0 ]; then
	runAsUser=minecraft
	runAsGroup=minecraft
	if [[ -v UID ]]; then
	if [[ $UID != 0 ]]; then
	if [[ $UID != $(id -u minecraft) ]]; then
	log "Changing uid of minecraft to $UID"
	usermod -u $UID minecraft
	fi
	else
	runAsUser=root
	fi
	fi
	if [[ -v GID ]]; then
	if [[ $GID != 0 ]]; then
	if [[ $GID != $(id -g minecraft) ]]; then
	log "Changing gid of minecraft to $GID"
	groupmod -o -g "$GID" minecraft
	fi
	else
	runAsGroup=root
	fi
	fi
	if isFalse "${SKIP_CHOWN_DATA}" && [[ $(stat -c "%u" /data) != "$UID" ]]; then
	log "Changing ownership of /data to $UID ..."
	chown -R ${runAsUser}:${runAsGroup} /data
	fi
	if [[ ${SKIP_NSSWITCH_CONF^^} != TRUE ]]; then
	echo 'hosts: files dns' > /etc/nsswitch.conf
	fi
	exec gosu ${runAsUser}:${runAsGroup} "$(dirname "$0")/start-configuration" "$@"

[tonydiethelm]

Ah! Thank you!

I know that's a little thing, but it was really bugging me.

And thanks for showing me the bit of code too. I always appreciate being shown stuff. :D

I guess I need to read up on the difference between PUID/PGID and UID/GID. :D I was going off documentation on Linuxserver.io.

Always Learning! And thanks again for hours of fun with my kiddos!

:D -Tony

[itzg]

That's just a convention they're using for their images

https://docs.linuxserver.io/general/understanding-puid-and-pgid/#:~:text=Using%20the%20PUID%20and%20PGID%20allows%20our%20containers%20to%20map%20the%20container's%20internal%20user%20to%20a%20user%20on%20the%20host%20machine.%20All%20of%20our%20containers%20use%20this%20method%20of%20user%20mapping%20and%20should%20be%20applied%20accordingly.

Us image authors can make up whatever environment variables we want. All that matters is that the variables are expected by the software/scripts running within the container. In my case UID/GUI. In their case PUID/PGID.