fix(commands): issues with dockerhost/podman

[Ajay-Satish-01]

Summary

Added --docker-host flag support to pack builder create command to enable compatibility with alternative container runtimes like Podman. This flag was already available in pack build but was missing from builder creation, causing issues when users needed to specify custom Docker daemon endpoints.

The implementation adds the --docker-host flag with the same functionality and description as the existing flag in pack build, allowing users to:

• Specify custom Docker daemon addresses (TCP, Unix socket)
• Use --docker-host=inherit to inherit from the DOCKER_HOST environment variable
• Maintain compatibility with Podman and other Docker-compatible runtimes

Output

Before

$ pack builder create buildpacks/builder:glibc --config ./builder.toml --docker-host=inherit
Error: unknown flag: --docker-host
Usage:
  pack builder create <image-name> --config <builder-config-path> [flags]

After

$ pack builder create buildpacks/builder:glibc --config ./builder.toml --docker-host=inherit
Pro tip: use --targets flag OR [[targets]] in builder.toml to specify the desired platform
# Command proceeds successfully (no unknown flag error)

$ pack builder create --help
...
      --docker-host string         Address to docker daemon that will be exposed to the build container.
                                   If not set (or set to empty string) the standard socket location will be used.
                                   Special value 'inherit' may be used in which case DOCKER_HOST environment variable will be used.
                                   This option may set DOCKER_HOST environment variable for the build container if needed.
...

Resolves

Fixes #2350

[jjbustamante]

Hi @Ajay-Satish-01

Thanks a lot for this PR!!!

The implementation for adding the new --docker-host flag to the pack builder create command is fine, but I think we are missing the ability to target the underlying error.

From the issue, I noticed this:

ERROR: invalid run image config: failed to fetch image: initializing source docker://localhost/bellsoft/buildpacks.alpaquita-run:glibc: pinging container registry localhost: Get "https://localhost/v2/": dial tcp [::1]:443: connect: connection refused

Which makes me think the error came from the image.Fetcher when we try to access the daemon, in this case. Your PR is passing through the configuration to the builder create command, but we are not using it. The difference between pack build and pack builder create or pack buildpack package is that when creating the builder or the buildpack pack is not spinning up a container, we build the OCI artifact on disk. Then we save it in the daemon or the OCI registry. If you check what we do with docker-host during pack build you will find we configure the docker run command to use it, but with builder create we don't run a container.

We need to check our Fetch implementation when the daemon is actually Podman. I think that's the missing part of your PR. What to do with docker-host value when fetching from daemon in Podman.

[jjbustamante]

PR is looking good! 🚀 but I think we still need to address the underlying error

[Ajay-Satish-01]

PR is looking good! 🚀 but I think we still need to address the underlying error

Thanks for the detailed explanation. Will look into it and get back if I have any questions.