How to deploy Firebase Storage rules to specific buckets?

Question

I'd like to know how storage rules deployment works in Firebase.

In Firebase Storage I have 2 buckets app.appspot.com and app-mybucket. On my local machine I have a storage.rules file which looks something like this:

service firebase.storage {
  match /b/app.appspot.com/o {
    match /{allPaths=**} {
      allow read, write: if request.auth != null;
    }
  }
  match /b/app-mybucket/o {
    match /{userId}/{allPaths=**} {
      allow read, write: if request.auth.uid == userId;
    }
  }
}

When I firebase deploy --only storage these rules get sent to the default app.appshpot.com bucket and nothing seems to get sent to app-mybucket. I'd like to know of a way I can deploy rules to all buckets.

Answer 1

In your firebase.json file, you can specify something like this:

  "storage": [{
    "rules": "my-appspot.rules",
    "bucket": "app.appspot.com"
  },
  {
    "rules": "my-bucket.rules",
    "bucket": "app-mybucket"
  }]

The example above uses different rules per bucket, you can use the same rules for each bucket as well if you'd like.

Answer 2

You can also use deploy targets. More info can be found here.

Example

1. Apply new target (in this case "main") using CLI

firebase target:apply storage main myproject.appspot.com myproject-eu myproject-ja

2. Update firebase.json

{
  "storage": [ {
      "target": "main",  // "main" is the applied target name for the group of Storage buckets
      "rules": "storage.main.rules"  // the file that contains the shared security rules
    }
  ]
}

3. Use

firebase deploy --only storage:main