apko-cache.md

Fetching and Caching Contents

To ensure efficient operation, the apko_image rule must maintain a cache of remote contents that it fetches from repositories. While outside of Bazel, apko manages its own cache, under Bazel, the cache must be maintained by Bazel to ensure correctness and speed. Therefore, Bazel needs to know what needs to be fetched and from where to cache these HTTP requests and provide them to apko as required.

The apko.lock.json file contains all the necessary information about how to perform the HTTP fetches required by apko to build the container image.

Generating the Lock File

Note: Documentation for lockfile generation will be added once the apko lock command is available.

Using translate_lock

Having just the apko/lock.json file alone is insufficient; all the information needs to be converted into apk_<content_type> repository calls to make them accessible to Bazel. The translate_lock tool accomplishes this by taking the apko.lock.json file and dynamically generating the required Bazel repositories.

translate_lock will create a new bazel repository named after itself. this repository will also have a target named contents, which you can pass to apko_image:

apko_image(
    name = "lock",
    config = "apko.yaml",
    # name of the repository is the same translate_lock!
    contents = "@examples_lock//:contents",
    tag = "lock:latest",
)

Usage with bzlmod

apk = use_extension("//apko:extensions.bzl", "apko")

apk.translate_lock(
    name = "examples_lock",
    lock = "//path/to/lock:apko.lock.json",
)
use_repo(apk, "examples_lock")

Usage with Workspace

load("@rules_apko//apko:translate_lock.bzl", "translate_apko_lock")

translate_apko_lock(
    name = "example_lock",
    lock = "//path/to/lock:apko.lock.json",
)

load("@example_lock//:repositories.bzl", "apko_repositories")

apko_repositories()