cmd: Fix paths when using an env file

[pascal-zarrad]

Description

Fix the behaviour of the environment variables XDG_DATA_HOME and XDG_CONFIG_HOME when supplied through an env file to match the expected one.

For further information, check #4273

Related Issues

Resolves #4273

Testing

• Caddy should create its data and config directories and files at the common location as always when no env file is specified using --envfile.
  • For example: /home/user/.local/share/caddy/<files and/or folders>
• When an env file is specified using --envfile, Caddy should use the environment variables XDG_DATA_HOME and XDG_CONFIG_HOME from the env file instead (instead) of the system ones. This should cause Caddy to create its files/directories at the location specified in the env file.
  • Example: Instead of /home/user/.local/share/caddy/autosave.json Caddy now uses /home/user/caddydata/caddy/autosave.json, when XDG_CONFIG_HOME was set to /home/user/caddydata in the env file.

[CLAassistant]

All committers have signed the CLA.

[mholt]

Thanks for the PR. (Sorry for how long it's taking me to get around to this issue.)

I'm very sensitive about adding new exported identifiers, and in this case I think we can avoid it. The function is only called in one place, so I think it'd be fair to just move that logic directly into the loadEnvFromFile() function, or, if you still want a separate function, move it next to loadEnvFromFile() and leave it unexported. (I don't think it needs to be a separate function though, personally.)

That sound alright?

[pascal-zarrad]

I agree that exporting this function isn't really necessary. Exporting it brings the risk of someone using it at a wrong spot in the future.

The logic has been moved to loadEnvFromFile(). I also brought the branch up to date.

[mholt]

Much better - thanks so much!