How do I publish an image locally?

[slim sluice]

I have an Earthfile that I use to build an image that's only used locally. Is it possible to export a local OCI image with Dagger? I tried searching docs/discord but it's still unclear to me.

[west kiln]

do you want to export it to your local filesystem, or a locally running registry, or a locally running docker engine?

[slim sluice]

local docker engine (OrbStack in my case)

I want to use the built image with Docker Compose

[west kiln]

@slim sluice from Dagger's point of view, your local docker/orbstack is just another local service running on your host. So you should approach it like any other client/server situation in your workflow, like for example if you were connecting to a DB running on your host

In the case of docker that means:

• Passing your host's docker unix socket as an argument to a function
• Running a docker client in a container with that unix socket mounted

There are a bunch of Dagger modules that do that

@novel portal @wild peak @ripe sparrow @knotty crow what docker module would you recommend? 👆

I know mine doesn't support external engines (I should add that...)

[slim sluice]

Would that require me to switch to a Dockerfile for the image? Or can I still build it with dag.container() ...?

[long sinew]

you can still build it with Dagger. The main difference is that your function will require the docker socket or a TCP endpoint service so you can push to it

[slim sluice]

Okay I think this makes sense. I can try later. Would love examples if anyone has some!

[long sinew]

1 sec

[long sinew]

here's a rough of example on how you can achieve it @slim sluice

 func (m *Lala) Test(
    ctx context.Context,
    docker *dagger.Socket,
) {

    c := dag.Container().From("alpine")

    dockerCli := dag.Container().From("docker:cli").WithUnixSocket("/var/run/docker.sock", docker).
        WithMountedFile("image.tar", c.AsTarball())
    out, _ := dockerCli.WithExec([]string{"docker", "load", "-i", "image.tar"}).Stdout(ctx)

    image := strings.TrimSpace(strings.SplitN(out, ":", 2)[1])

    dockerCli.WithExec([]string{"docker", "tag", image, "mycustomimg"}).Sync(ctx)
}

[slim sluice]

This is super helpful, thank you!! this is the last thing I need to complete my monorepo migration from Earthly

[west kiln]

Here's my module if it helps: https://daggerverse.dev/mod/github.com/shykes/x/docker

If only to take inspiration and copy-paste 🙂

Ah man, it actually does support external engines, but you need to make it a Service type. And at the moment that type only supports TCP and UDP endpoints, not unix sockets

[west kiln]

@slim sluice I figured out how to use my module the way you need it 🙂