How do I set environment variables to agent (like /etc/default/go-agent)

[MPV]

What I'd like to do:
Run scripts that set environment variables, which become available to my agents.

Steps I've done:

1. I've created a Docker image based on this image (gocd/gocd-agent-docker-dind specifically).
2. I've added some scripts I'd like to run in /etc/profile.d/, for example this one:

$ cat /etc/profile.d/add-python-scripts-to-path.sh
#!/bin/false

export PATH="/home/go/.local/bin:$PATH"

3. I've created the /etc/default/go-agent file, and have it load /etc/profile:

$ cat /etc/default/go-agent
. /etc/profile

4. ...and /etc/profile in turn should load the files in /etc/profile.d:

$ tail -n5 /etc/profile
for script in /etc/profile.d/*.sh ; do
        if [ -r $script ] ; then
                . $script
        fi
done

...however when I run jobs using this image, my scripts haven't been run, and the environment variables aren't set.

Questions:

1. Am I configuring the right file? (/etc/default/go-agent)
2. Am I running without service_mode? I suppose I am (?) — and then my guess (judging from /go-agent/agent.sh) is that maybe my file won't be loaded:

$ grep "/etc/default" -B 1 -A 5 /go-agent/agent.sh
if [ "$2" == "service_mode" ]; then
  if [ -f /etc/default/${SERVICE_NAME} ]; then
    . /etc/default/${SERVICE_NAME}
  fi

  # no point in not daemonizing the service
  DAEMON=Y
fi

3. If that's the case, is there another way I should be telling the gocd agent to run my files for setting environment variables etc?

[ketan]

I'd probably try adding scripts in /docker-entrypoint.d and see if that works as expected? See

docker-gocd-agent/docker-entrypoint.sh.erb

Lines 113 to 124 in 2b25324

	yell "Running custom scripts in /docker-entrypoint.d/ ..."
	# to prevent expansion to literal string `/docker-entrypoint.d/*` when there is nothing matching the glob
	shopt -s nullglob
	for file in /docker-entrypoint.d/*; do
	if [ -f "$file" ] && [ -x "$file" ]; then
	try "$file"
	else
	yell "Ignoring $file, it is either not a file or is not executable"
	fi
	done

[MPV]

Oh maybe I've interpreted it wrong... I thought /docker-entrypoint.d was only run as root?

I want my scripts to be run as the go user (to be set for pipeline jobs).

I thought this line made it run /goagent/agent.sh as the go user, using gosu:

docker-gocd-agent/docker-entrypoint.sh.erb

Line 126 in 2b25324

try exec /usr/local/sbin/tini -- /usr/local/sbin/gosu go "$0" "$@"

...but maybe it's running itself again and thus loading /docker-entrypoint.d/ files, also as go?

[MPV]

This is what led me to configure the /etc/default/go-agent file from before:

Users can override default startup arguments for a GoCD agent in a Linux machine by editing the file etc/default/go-agent.

https://docs.gocd.org/current/installation/install/agent/linux.html#overriding-default-startup-arguments-and-environment

[MPV]

@ketan Looking at the logs of my container, I see this happening during startup:

/docker-entrypoint.sh: Creating directories and symlinks to hold GoCD configuration, data, and logs
[...]
$ chown go:go /go/config/autoregister.properties
/docker-entrypoint.sh: Running custom scripts in /docker-entrypoint.d/ ...
$ exec /usr/local/sbin/tini -- /usr/local/sbin/gosu go /docker-entrypoint.sh /go-agent/agent.sh
/docker-entrypoint.sh: line 57: /usr/local/bin/nohup.out: Permission denied
$ exec /go-agent/agent.sh
[Thu Sep 06 11:18:35 GMT 2018] Starting process:
[...]

...thus it doesn't seem like it runs those files in /docker-entrypoint.d as go, but only as root?

Any suggestions of what I could try?

[ketan]

@MPV

Here's how things have been designed:

• Stuff in /docker-entrypoint.d executes as root user, intentionally so. Use this to provision, install packages etc.
• Stuff in /etc/default/go-agent is sourced from the agent startup script (/goagent/agent.sh). Use this to ensure that variables are available to the agent process (which runs as the go user). This file can be volume mounted (or baked into the image, as the case may be).