Check for DATABASE_URL in Heroku release phase command (#1302)

* Check for DATABASE_URL in Heroku release phase command

When creating review apps, sometimes the database isn't provisioned until after the first build and release are executed, which causes a release phase command failure. This change adds a guard to the release phase command to prevent that case. It shouldn't impact production at all because the database will always be provisioned.

* Tweak

* Try script

* update

* Remove postdeploy script

There's no visibility into the running of this script in the Heroku dashboard, so it's better to just run it manually if it's something you want.

Procfile

@@ -1,4 +1,4 @@
-release: alembic upgrade head
+release: ./heroku-release-phase.sh
 web: gunicorn server.app:app --preload
 worker: python -m server.worker.worker
-slack_worker: python -m server.activity_log.slack_worker
+slack_worker: python -m server.activity_log.slack_worker

app.json

@@ -23,8 +23,5 @@
     }
   },
   "name": "arlo",
-  "scripts": {
-    "postdeploy": "heroku pg:backups:restore vx-arlo-staging:: -a $HEROKU_APP_NAME --confirm $HEROKU_APP_NAME"
-  },
   "stack": "heroku-18"
 }

heroku-release-phase.sh

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+echo "Attempting to run migrations"
+if [[ $DATABASE_URL ]]; then
+    alembic upgrade head
+else
+    echo "DATABASE_URL not set, skipping migrations"
+fi