CI: add promotion step for publish grafanacom (#93851)

* add promotion step for publish grafanacom

* publish-grafanacom depends on compile-build-cmd

* use DRONE_TAG

* add docstring comment for depends_on

scripts/drone/events/release.star

@@ -242,6 +242,17 @@ def publish_packages_pipeline():
             depends_on = deps,
             environment = {"EDITION": "oss"},
         ),
+        pipeline(
+            name = "publish-grafanacom",
+            trigger = {
+                "event": ["promote"],
+                "target": "publish-grafanacom",
+            },
+            steps = [
+                compile_build_cmd(),
+                publish_grafanacom_step(ver_mode = "release", depends_on = ["compile-build-cmd"]),
+            ],
+        ),
     ]
 
 def publish_npm_pipelines():

scripts/drone/steps/lib.star

@@ -727,6 +727,7 @@ def frontend_metrics_step(trigger = None):
     Returns:
       Drone step.
     """
+
     step = {
         "name": "publish-frontend-metrics",
         "image": images["node"],
@@ -1178,7 +1179,7 @@ def upload_packages_step(ver_mode, trigger = None):
         step = dict(step, when = trigger)
     return step
 
-def publish_grafanacom_step(ver_mode):
+def publish_grafanacom_step(ver_mode, depends_on = ["publish-linux-packages-deb", "publish-linux-packages-rpm"]):
     """Publishes Grafana packages to grafana.com.
 
     Args:
@@ -1186,6 +1187,7 @@ def publish_grafanacom_step(ver_mode):
         variable as the value for the --build-id option.
         TODO: is this actually used by the grafanacom subcommand? I think it might
         just use the environment variable directly.
+      depends_on: what other steps this one depends on (strings)
 
     Returns:
       Drone step.
@@ -1203,10 +1205,7 @@ def publish_grafanacom_step(ver_mode):
     return {
         "name": "publish-grafanacom",
         "image": images["publish"],
-        "depends_on": [
-            "publish-linux-packages-deb",
-            "publish-linux-packages-rpm",
-        ],
+        "depends_on": depends_on,
         "environment": {
             "GRAFANA_COM_API_KEY": from_secret("grafana_api_key"),
             "GCP_KEY": from_secret(gcp_grafanauploads_base64),