Drone: Trigger Enterprise PR checks for OSS PRs (#47176)

* Drone: add enterprise-init-downstream step

* fixes

* Add OSS_PULL_REQUEST env variable for downstream builds

* sign Drone config

* Update .drone.yml

* use test grabpl

* test without init step

* fix downstream branch

* unknown branch test

* use drone-downstream test image

* revert latest changes

* update Drone and add GH workflow

* fix PR number

* Run Enterprise PR check only on PRs targeting main or release branch

* update repository dispatch action

* remove test data

* update grabpl version

scripts/drone/pipelines/main.star

@@ -129,7 +129,7 @@ def get_steps(edition):
     ]
     build_steps = [
         trigger_test_release(),
-        enterprise_downstream_step(edition=edition),
+        enterprise_downstream_step(edition=edition, ver_mode=ver_mode),
         build_backend_step(edition=edition, ver_mode=ver_mode),
         build_frontend_step(edition=edition, ver_mode=ver_mode),
         build_frontend_package_step(edition=edition, ver_mode=ver_mode),

scripts/drone/pipelines/pr.star

@@ -32,6 +32,7 @@ load(
     'validate_scuemata_step',
     'ensure_cuetsified_step',
     'test_a11y_frontend_step',
+    'enterprise_downstream_step',
 )
 
 load(
@@ -118,6 +119,7 @@ def pr_pipelines(edition):
         yarn_install_step(),
     ]
     build_steps = [
+        enterprise_downstream_step(edition=edition, ver_mode=ver_mode),
         build_backend_step(edition=edition, ver_mode=ver_mode, variants=variants),
         build_frontend_step(edition=edition, ver_mode=ver_mode),
         build_frontend_package_step(edition=edition, ver_mode=ver_mode),

scripts/drone/steps/lib.star

@@ -1,6 +1,6 @@
 load('scripts/drone/vault.star', 'from_secret', 'github_token', 'pull_secret', 'drone_token', 'prerelease_bucket')
 
-grabpl_version = 'v2.9.41'
+grabpl_version = 'v2.9.48'
 build_image = 'grafana/build-container:1.5.4'
 publish_image = 'grafana/grafana-ci-deploy:1.3.1'
 deploy_docker_image = 'us.gcr.io/kubernetes-dev/drone/plugins/deploy-image'
@@ -181,27 +181,38 @@ def lint_drone_step():
         ],
     }
 
-
-def enterprise_downstream_step(edition):
+def enterprise_downstream_step(edition, ver_mode):
     if edition in ('enterprise', 'enterprise2'):
         return None
 
-    return {
+    repo = 'grafana/grafana-enterprise@'
+    if ver_mode == 'pr':
+        repo += '${DRONE_SOURCE_BRANCH}'
+    else:
+        repo += 'main'
+
+    step = {
         'name': 'trigger-enterprise-downstream',
         'image': 'grafana/drone-downstream',
         'settings': {
             'server': 'https://drone.grafana.net',
             'token': from_secret(drone_token),
             'repositories': [
-                'grafana/grafana-enterprise@main',
+                repo,
             ],
             'params': [
                 'SOURCE_BUILD_NUMBER=${DRONE_COMMIT}',
                 'SOURCE_COMMIT=${DRONE_COMMIT}',
+                'OSS_PULL_REQUEST=${DRONE_PULL_REQUEST}',
             ],
         },
     }
 
+    if ver_mode == 'pr':
+        step.update({ 'failure': 'ignore' })
+
+    return step
+
 
 def lint_backend_step(edition):
     return {