chore: add e2e test for crane as registry (#109)

Author: thesayyn

.bcr/presubmit.yml

@@ -1,5 +1,5 @@
 bcr_test_module:
-  module_path: "e2e/smoke"
+  module_path: "e2e/crane_as_registry"
   matrix:
     platform: ["debian10", "macos", "ubuntu2004", "windows"]
   tasks:

.github/workflows/ci.yaml

@@ -23,7 +23,13 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest]
-        folder: [".", "e2e/custom_registry", "e2e/wasm", "e2e/smoke"]
+        folder:
+          - .
+          - e2e/custom_registry
+          - e2e/wasm
+          - e2e/smoke
+          - e2e/crane_as_registry
+
         bzlmodEnabled: [true, false]
         exclude:
           - folder: e2e/custom_registry

README.md

@@ -44,6 +44,10 @@ rules_oci does not contain language-specific rules, but we do document how to ac
 There are more examples of usage in the [examples](https://github.com/bazel-contrib/rules_oci/tree/main/examples) folder.
 Note that the examples rely on the setup code in the `/WORKSPACE` file in the root of this repo.
 
+### Choosing between zot or crane as the local registry
+
+rules_oci supports two different registry implementation for the temporary storage within actions spawned by bazel. By default we recommend using `zot` as it stores blobs on disk and is memory efficient but doesn't support `Docker` images. On the other hand, crane is memory hungry as it stores blobs in memory leading to high memory usage but crane supports both `OCI` and `Docker` images which is quite useful for using `Docker` images pulled from the registries such as `Docker Hub`.
+
 # Public API
 
 ## Construct image layers

e2e/crane_as_registry/.bazelrc

@@ -0,0 +1 @@
+test --test_env=DOCKER_HOST

e2e/crane_as_registry/BUILD.bazel

@@ -0,0 +1,31 @@
+load("@rules_oci//oci:defs.bzl", "oci_image", "oci_tarball", "structure_test")
+
+oci_image(
+    name = "image",
+    architecture = select({
+        "@platforms//cpu:arm64": "arm64",
+        "@platforms//cpu:x86_64": "amd64",
+    }),
+    cmd = [
+        "--arg1",
+        "--arg2",
+    ],
+    entrypoint = ["/custom_bin"],
+    env = {
+        "ENV": "/test",
+    },
+    os = "linux",
+)
+
+oci_tarball(
+    name = "tar",
+    image = ":image",
+    repotags = [],
+)
+
+structure_test(
+    name = "test",
+    config = ["test.yaml"],
+    driver = "tar",
+    image = ":tar",
+)

e2e/crane_as_registry/MODULE.bazel

@@ -0,0 +1,8 @@
+"Bazel dependencies"
+bazel_dep(name = "rules_oci", dev_dependency = True, version = "0.0.0")
+bazel_dep(name = "platforms", version = "0.0.5")
+
+local_path_override(
+    module_name = "rules_oci",
+    path = "../..",
+)

e2e/crane_as_registry/WORKSPACE.bazel

@@ -0,0 +1,21 @@
+workspace(name = "crane_as_registry")
+
+local_repository(
+    name = "rules_oci",
+    path = "../../",
+)
+
+load("@rules_oci//oci:dependencies.bzl", "rules_oci_dependencies")
+
+rules_oci_dependencies()
+
+load("@rules_oci//oci:repositories.bzl", "LATEST_CRANE_VERSION", "oci_register_toolchains")
+
+oci_register_toolchains(
+    name = "oci",
+    crane_version = LATEST_CRANE_VERSION,
+)
+
+load("@rules_pkg//:deps.bzl", "rules_pkg_dependencies")
+
+rules_pkg_dependencies()

e2e/crane_as_registry/WORKSPACE.bzlmod

@@ -0,0 +1 @@
+# This file replaces WORKSPACE.bazel when --enable_bzlmod is set

e2e/crane_as_registry/test.yaml

@@ -0,0 +1,8 @@
+schemaVersion: "2.0.0"
+
+metadataTest:
+  envVars:
+    - key: "ENV"
+      value: "/test"
+  entrypoint: ["/custom_bin"]
+  cmd: ["--arg1", "--arg2"]