Firestore Collection Group Permission

If you are using Firestore Collection Group, you need to specifiy special rules for the permission.

Indexed

I store data in blog/post, where I want to allow query across post using the following composite index

Collection ID: post Fields indexed: processed Ascending date Descending Query scope: Collection group

Query via collection group

let query = db.collectionGroup('post').where('processed', '==', false).orderBy('date', 'desc').limit(100)

Firestore Rules

  // collection group
  match /{path=**}/post/{postId} {
    allow read: if true;
  }