A newbie query on imagebuildah.BuildDockerfiles()

[santoshkal]

Hi everyone,

I'm new to Buildah and I'm trying to build a container from a Dockerfile using imagebuildah.BuildDockerfiles(). I've used the same storage.Store and define.BuildOptions as in the tests.

Here's a snippet of my code:

func runBuildCmd(cmd *cobra.Command, args []string) error {
        // ...
	if buildah.InitReexec() {
		return fmt.Errorf("Error initializing: %v", cmd)
	}
	unshare.MaybeReexecUsingUserNamespace(false)
	// ...
        // var buildStore storage.Store
	buildStore, err := storage.GetStore(buildStoreOptions)
	if err != nil {
		panic(err)
	}
	defer func() {
		if _, err := buildStore.Shutdown(false); err != nil {
			if !errors.Is(err, storage.ErrLayerUsedByContainer) {
				fmt.Printf("Failed to shutdown storage: %q", err)
			}
		}
	}()
	// ...
	buildOptions := define.BuildOptions{
		ContextDirectory: buildArgs.reqinput,
		NamespaceOptions: []define.NamespaceOption{
			{Name: string(specs.NetworkNamespace), Host: true},
		},
	}

	ctx := context.TODO()
	id, ref, err := img.BuildDockerfiles(ctx, buildStore, buildOptions, dockerfile)
	if err != nil {
		return fmt.Errorf("Error building container from %s: %v", buildArgs.reqinput, err)
	}
	fmt.Printf("image %v created successfully with %v digest %v", id, ref)
	return nil
}

When I try to build this, I encounter the following error:

➜  genval git:(rego-results) ✗ go build -o ./bin/genval .
# github.com/containers/image/v5/storage
../go/pkg/mod/github.com/containers/image/[email protected]/storage/storage_dest.go:386:53: aLayer.UncompressedDigest undefined (type "github.com/containers/storage".AdditionalLayer has no field or method UncompressedDigest)

I am importing github.com/containers/storage. Can someone please help me understand what's going wrong?

Thank you!

[nalind]

This was not an error you made - the storage library changed an API that the image library was using. If you temporarily force github.com/containers/storage down to v1.53.0, I think it'll clear up.

I realize now that it's not something that's explicitly said in the godoc for buildah.InitReexec(), but when buildah.InitReexec() retuns true, it's not an error, and main() should return with no error and an exit status of 0. It's something you'd have run into eventually.

[nalind]

The error message indicates that it's looking for netavark. This check happens before the network configuration is evaluated, so you'll need to make sure it's installed.

[santoshkal]

Thank you.

Could you please direct me to resources that will help me install the netavark and resolve the errors?
I also examined tests/tutorial/tutorial.go and observed the same behavior.

[nalind]

Your OS distribution may have packages of it already, otherwise you'll need to build it from sources at https://github.com/containers/netavark.

[santoshkal]

I can build an image with netavark package installed. Thanks a lot for your help.

I had another query. Can I build an image from my Go build tool with any other network backend than netavark?

[nalind]

The github.com/containers/common library provides netavark and CNI. But it's source code, so anything that implements the right Go interface should work, give or take bugs.