load

Load an oci_image into runtimes such as podman and docker. Intended for use with bazel run.

For example, given an :image target, you could write

oci_load(
    name = "load",
    image = ":image",
    repo_tags = ["my-repository:latest"],
)

and then run it in a container like so:

bazel run :load
docker run --rm my-repository:latest

Rules

oci_load

Loads an OCI layout into a container daemon without needing to publish the image first.

Passing anything other than oci_image to the image attribute will lead to build time errors.

Build Outputs

The default output is an mtree specification file. This is because producing the tarball in bazel build is expensive, and should typically not be an input to any other build actions, so producing it only creates unnecessary load on the action cache.

If needed, the tarball output group allows you to depend on the tar output from another rule.

On the command line, bazel build //path/to:my_tarball --output_groups=tarball

or in a BUILD file:

oci_load(
    name = "my_tarball",
    ...
)
filegroup(
    name = "my_tarball.tar",
    srcs = [":my_tarball"],
    output_group = "tarball",
)

When using format = "oci"

When using format = oci, containerd image store needs to be enabled in order for the oci style tarballs to work.

On docker desktop this can be enabled by visiting Settings (cog icon) -> Features in development -> Use containerd for pulling and storing images

For more information, see https://docs.docker.com/desktop/containerd/

Multiple images

To load more than one image into the daemon, use rules_multirun to group multiple oci_load targets into one executable target.

This might be useful with a docker-compose workflow, for example.

load("@rules_multirun//:defs.bzl", "command", "multirun")

IMAGES = {
    "webservice": "//path/to/web-service:image.load",
    "backend": "//path/to/backend-service:image.load",
}

[
    command(
        name = k,
        command = v,
    )
    for (k, v) in IMAGES.items()
]

multirun(
    name = "load_all",
    commands = IMAGES.keys(),
)

Example usage (generated):

load("@rules_oci//oci/private:load.bzl", "oci_load")

oci_load(
    # A unique name for this target.
    name = "",
    # Label of a directory containing an OCI layout, typically `oci_image`
    image = "",
    # a file containing repo_tags, one per line.
    repo_tags = "",
)

name

Required name.

A unique name for this target.

format

Optional string. Default: "docker"

Format of image to generate. Options are: docker, oci. Currently, when the input image is an image_index, only oci is supported, and when the input image is an image, only docker is supported. Conversions between formats may be supported in the future.

image

Required label.

Label of a directory containing an OCI layout, typically oci_image

repo_tags

Required label.

a file containing repo_tags, one per line.

loader

Optional label. Default: None

Alternative target for a container cli tool that will be used to load the image into the local engine when using bazel run on this target.

By default, we look for docker or podman on the PATH, and run the load command.

See the _run_template attribute for the script that calls this loader tool.