Opt-in/out for .env being written

[Alexnortung]

Previously discussed on discord

When you deploy an application coolify writes a .env file.

In some frameworks the .env file is used as defaults environment variables, which should be commited and for those that should not be committed you can use .env.local. (how nextjs handles .env)

My problem is that coolify OVERWRITES the .env file, which broke my application.

I think it should be opt-in to have the .env file written as no other docker platforms have this behavior.
Additionally it would make sense to choose where the .env file is written to, it might not always be in the root directory and it could also be .env.local that you wanted to be written.

[djsisson]

@Alexnortung

imo coolify should not inject the .env file at all when building an image. In certain circumstances, you can even end up exposing it if using static site.

This is also one of the long standing issues with nixpacks preview build args, where for preview builds it doesn't create a .env file but a .env.pr-x file which no framework will read.

There is a series of mistakes when dealing with env:

Currently when building an image, the .env is added to the cloned repo, before docker build is ran, however this isn't needed at all, since all build args are passed in on the cli.
Coolify will then add a series of ARG XXXX to the top of the dockerfile which does nothing in a multistage dockerfile since ARG are scoped to the stage they are in.
However for nixpacks which is a single stage dockerfile the ARG commands are not added, so for nixpacks you are relying on the .env file when building, but which doesn't exist in preview builds.
Lastly for compose based builds, its ok to inject random named env file as long as it is added to the .dockerignore file, that way when docker compose build is ran with --env_file passed in, compose can correctly interpolate any build args you have added to the compose file

for runtime, the .env file is also saved in the configuration directory and just passed in with the compose file so they get correctly interpolated and added to the environment

tldr
.env + .env.pr-x should not be added to cloned repo when building image
ARG XXX do not need to be added to top of dockerfiles
ARG XXX do need to be added to top of nixpacks dockerfile
for compose based builds a .env.xxxxxx can be added as long as its also added to the .dockerignore so it isn't part of the context when copying files.

I personally would never have a .env in a repo since it would not be part of the final build, unless you specifically copy it over