k8s_deploy api for images already in registry (adobe#108)

README.md

@@ -83,6 +83,7 @@ When you run `bazel run ///helloworld:mynamespace.apply`, it applies this file i
 | ***image_repository***    | `None`         | The repository to push images to. By default, this is generated from the current package path.
 | ***image_repository_prefix*** | `None`     | Add a prefix to the image_repository. Can be used to upload the images in
 | ***not_gitops_image_repository_prefix*** | `{BUILD_USER}`     | Add a prefix to the image_repository when gitops == False for the .apply|.delete targets
+| ***image_pushes***        | `[]`           | A list of labels implementing K8sPushInfo referring image uploaded into registry. See [Injecting Docker Images](#injecting-docker-images).
 | ***release_branch_prefix*** | `master`     | A git branch name/prefix. Automatically run GitOps while building this branch. See [GitOps and Deployment](#gitops_and_deployment).
 | ***deployment_branch***   | `None`         | Automatic GitOps output will appear in a branch and PR with this name. See [GitOps and Deployment](#gitops_and_deployment).
 | ***gitops_path***         | `cloud`        | Path within the git repo where gitops files get generated into
@@ -318,6 +319,25 @@ Docker image and the files in the image. So for example, here's what will happen
 1. A new `helloworld` manifest will be rendered using the new image
 1. The new `helloworld` pod will be deployed
 
+It is possible to use alternative ways to resolve images as long as respective rule implements K8sPushInfo provider. For example, this setup will mirror the referred image into a local registry and provide a reference to it. `k8s_deploy` will need to use `image_pushes` parameter:
+
+```starlark
+load("@com_fasterci_rules_mirror//mirror:defs.bzl", "mirror_image")
+mirror_image(
+    name = "agnhost_image",
+    digest = "sha256:93c166faf53dba3c9c4227e2663ec1247e2a9a193d7b59eddd15244a3e331c3e",
+    dst_prefix = "gcr.io/myregistry/mirror",
+    src_image = "registry.k8s.io/e2e-test-images/agnhost:2.39",
+)
+k8s_deploy(
+    name = "agnhost",
+    manifests = ["agnhost.yaml"],
+    image_pushes = [
+        ":agnhost_image",
+    ]
+)
+```
+
 
 <a name="adding-dependencies"></a>
 ### Adding Dependencies

skylib/k8s.bzl

@@ -123,6 +123,7 @@ def k8s_deploy(
         image_registry = "docker.io",  # registry to push container to. jenkins will need an access configured for gitops to work. Ignored for mynamespace.
         image_repository = None,  # repository (registry path) to push container to. Generated from the image bazel path if empty.
         image_repository_prefix = None,  # Mutually exclusive with 'image_repository'. Add a prefix to the repository name generated from the image bazel path
+        image_pushes = [],  # list of targets implementing K8sPushInfo provider, representing reference to image already in a registry.
         objects = [],
         omit_image_tag_in_gitops = False,
         gitops = True,  # make sure to use gitops = False to work with individual namespace. This option will be turned False if namespace is '{BUILD_USER}'
@@ -162,7 +163,7 @@ def k8s_deploy(
         # Mynamespace option
         if not namespace:
             namespace = "{BUILD_USER}"
-        image_pushes = _image_pushes(
+        image_pushes = image_pushes + _image_pushes(
             name_suffix = "-mynamespace.push",
             images = images,
             image_registry = image_registry,
@@ -228,7 +229,7 @@ def k8s_deploy(
         # gitops
         if not namespace:
             fail("namespace must be defined for gitops k8s_deploy")
-        image_pushes = _image_pushes(
+        image_pushes = image_pushes + _image_pushes(
             name_suffix = ".push",
             images = images,
             image_registry = image_registry,