feat(artifact-registry): add support for code repositories with multiple apps

Add a variable called ARTIFACT_REGISTRY_IMAGE_NAME to allow the names assigned to images pushed to Artifact Registry to be overridden. This supports the situation where multiple apps are present in the same source code repository as the image name can be customised for each app.

Closes #65 (closed)

auto-devops/artifact-registry.yml

@@ -23,6 +23,10 @@
 # ARTIFACT_REGISTRY_SERVICE_ACCOUNT: This is the email account of a service account which has permission to push to the
 #   $ARTIFACT_REGISTRY_DOCKER_REPOSITORY. The gke_ci_run service account configured by the gitlab-runner-infrastructure
 #   code must have permission to impersonate this service account.
+#
+# ARTIFACT_REGISTRY_IMAGE_NAME:
+#   Optional. This is the name that will be assigned to images that are pushed to the docker registry. Defaults to
+#   `$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG`, or `$CI_PROJECT_NAME` when there is no commit tag.
 
 .artifact-registry-base:
   image: registry.gitlab.developers.cam.ac.uk/uis/devops/infra/dockerimages/gcloud-docker:latest
@@ -38,11 +42,11 @@
     # See https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/ci/templates/Jobs/Build.gitlab-ci.yml
     if [[ -z "$CI_COMMIT_TAG" ]]; then
       export CI_APPLICATION_REPOSITORY=${CI_APPLICATION_REPOSITORY:-$CI_REGISTRY_IMAGE/$CI_COMMIT_REF_SLUG}
-      export CI_ARTIFACT_REGISTRY_REPOSITORY=$ARTIFACT_REGISTRY_DOCKER_REPOSITORY/$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG
+      export CI_ARTIFACT_REGISTRY_REPOSITORY=$ARTIFACT_REGISTRY_DOCKER_REPOSITORY/${ARTIFACT_REGISTRY_IMAGE_NAME:-$CI_PROJECT_NAME/$CI_COMMIT_REF_SLUG}
       export CI_APPLICATION_TAG=${CI_APPLICATION_TAG:-$CI_COMMIT_SHA}
     else
       export CI_APPLICATION_REPOSITORY=${CI_APPLICATION_REPOSITORY:-$CI_REGISTRY_IMAGE}
-      export CI_ARTIFACT_REGISTRY_REPOSITORY=$ARTIFACT_REGISTRY_DOCKER_REPOSITORY/$CI_PROJECT_NAME
+      export CI_ARTIFACT_REGISTRY_REPOSITORY=$ARTIFACT_REGISTRY_DOCKER_REPOSITORY/${ARTIFACT_REGISTRY_IMAGE_NAME:-$CI_PROJECT_NAME}
       export CI_APPLICATION_TAG=${CI_APPLICATION_TAG:-$CI_COMMIT_TAG}
     fi