Add podman buildx version support

[rhatdan]

Fixes: #16793

Signed-off-by: Daniel J Walsh [email protected]

Does this PR introduce a user-facing change?

podman buildx --version now shows buildah version.

[Luap99]

Let's wait for an answer to #16793 (comment). I have the feeling we need podman buildx version and not a flag.

[rhatdan]

@Luap99 Switched to podman buildx version.

[vrothberg]

@flouthoc PTAL

I am not sure whether returning the Buildah version may confuse clients? The buildx is version is something different.

[rhatdan]

I thought about impersonating the buildx version, but that felt wrong, and not something we could even guarantee.
We only implement parts that people ask about.

[vrothberg]

I thought about impersonating the buildx version, but that felt wrong, and not something we could even guarantee. We only implement parts that people ask about.

I would have done the very same thing. @flouthoc has probably the most experience with buildkit, so I prefer to a head node from him.

[Luap99]

The problem is that a external tool is calling this command which likely means that it tires to parse the output, so having non matching output will just defer the error one step later.

[flouthoc]

Hmm upon checking docker buildx version is supported but docker buildx --version is not.

sudo docker buildx version
github.com/docker/buildx v0.8.0-71-g6854eec4 6854eec48de2fa05fadbce978dd9d7de848e82fb
[fl@fedora secretdir3]$ sudo docker buildx --version
unknown flag: --version
See 'docker buildx --help'.

Usage:  docker buildx [OPTIONS] COMMAND

Extended build capabilities with BuildKit

Options:
      --builder string   Override the configured builder instance

Management Commands:
  imagetools  Commands to work on images in registry

Commands:
  bake        Build from a file
  build       Start a build
  create      Create a new builder instance
  du          Disk usage
  inspect     Inspect current builder instance
  ls          List builder instances
  prune       Remove build cache
  rm          Remove a builder instance
  stop        Stop builder instance
  use         Set the current builder instance
  version     Show buildx version information

Run 'docker buildx COMMAND --help' for more information on a command.

I think we should also support buildx version for compat.

[vrothberg]

I think we should also support buildx version for compat.

That's what the PR does. I just wonder whether the output is useful. I share Paul's comment on deferring the error to a later point. Maybe it's better to explicitly error out? Some clients may misinterpret the output and run into hard to debug failures after?

[rhatdan]

@albinkc could you check to see if this would fix your problem or just confuse the tool? IE is the tool using this information for display purposes or actually making assumptions on the version returned.

[flouthoc]

@vrothberg @Luap99 anything depending upon the output of buildx version will break either we print the buildah version or print error its just the the matter it will break early or later.

This analogy is also true for podman version since output of podman version is different than docker version so we are breaking compat there as well for users who are aliasing docker with podman so I don't think we could do much here.

[rhatdan]

I agree I think we just merge this and then allow the users to deal with the differences in versions. All we can do is match the CLI not necessarily the CLI output.

[vrothberg]

LGTM

[flouthoc]

LGTM
/lgtm
/approve

[openshift-ci]

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