New environment variable to specify bake file(s)

[rrjjvv]

Description

It would be nice to have an environment variable like BAKE_FILE, analogous to COMPOSE_FILE in compose, to allow specifying the bake file(s) to execute. For example, I'd like to replace

$ docker buildx bake -f docker-bake.hcl -f docker-bake.test.hcl <target>

with

$ export BAKE_FILE='docker-bake.hcl:docker-bake.test.hcl'
$ docker buildx bake <target>

My actual problem (annoyance) is having to continually specify two -f arguments for every command. For readability, I chose to split up my primary targets from my targets dedicated to testing. I know I could technically solve this simply renaming my second file to docker-bake.override.hcl. But in reality, it's not an override file; it's 100% additive with no overriding or merging. Even though the second file is additive, it's not independent; it uses functions defined in the primary file, which is why I have to specify both files in order to build a target in the second.

Something like import: "docker-bake.test.hcl" would also solve my problem. Obviously that also has precedent in compose (and would actually be even cleaner/friendlier in my case), but I assumed the environment variable would be more likely to get a thumbs up, and of course, much simpler to implement.

[crazy-max]

Sounds good to me but would opt for BUILDX_BAKE_FILE env var so we are consistent with current ones: https://docs.docker.com/build/building/variables/#build-tool-configuration-variables

[rrjjvv]

Cool. Not that I personally need/want it, but I assume there should be a corresponding BUILDX_BAKE_PATH_SEPARATOR as well, with same defaults/functionality as the compose equivalent?

I haven't actually looked yet, but it seems like it should be pretty straight-forward and could implement this if you'd like (but will be a couple days before I can spend time on it).

[tonistiigi]

Sounds good to me but would opt for BUILDX_BAKE_FILE env

Looks like we have some inconsistencies betweenBAKE_ and BUILDX_BAKE_ env variables. Should try to fix these (with backwards compatibility).

[crazy-max]

Sounds good to me but would opt for BUILDX_BAKE_FILE env

Looks like we have some inconsistencies betweenBAKE_ and BUILDX_BAKE_ env variables. Should try to fix these (with backwards compatibility).

Oh indeed we have some inconsistencies.

[rrjjvv]

I'll assume that you still consider BUILDX_BAKE_ to be the correct variant and that addressing the 'wrong' ones is not a blocker for this feature, unless you say otherwise. Obviously this feature will use (only) the correct style.

[crazy-max]

I'll assume that you still consider BUILDX_BAKE_ to be the correct variant and that addressing the 'wrong' ones is not a blocker for this feature, unless you say otherwise. Obviously this feature will use (only) the correct style.

Yes I think BUILDX_BAKE_ is the right choice. I took a look at the current state:

• BUILDX_BAKE_GIT_AUTH_HEADER
• BUILDX_BAKE_GIT_AUTH_TOKEN
• BUILDX_BAKE_GIT_SSH
• BUILDX_BAKE_ENTITLEMENTS_FS
• BAKE_ALLOW_REMOTE_FS_ACCESS

So the only one to align would be BAKE_ALLOW_REMOTE_FS_ACCESS.

BAKE_CMD_CONTEXT and BAKE_LOCAL_PLATFORM are not env vars but built-in variables so should be kept as-is: https://docs.docker.com/build/bake/reference/#built-in-variables