Firestore Firebase Database Rules

Question

I'm trying to set up access rules for my Firestore Firebase database.
(ala. https://firebase.google.com/docs/firestore/security/get-started)

I want 3 rules :

1. No access to all tables, except
2. Table public_data has read access for everyone, and
3. Table user_data has read, write for just that authenticated user
   (and I guess anyone should be able to create a new user too .. thats a bonus rule)

The rule format seems straight forward enough from the documentation, however using the Simulator available under console.firebase.google.com > Database > Cloud Firestore > (my db) > Rules > Simulator the results are not what I expect.

Answer 1

Here is what I ended up using :

(https://console.firebase.google.com/u/0/project/[MY_PROJECT_NAME]/database/firestore/rules)

rules_version = '2';
service cloud.firestore {

  match /databases/{database}/documents {

    // 2. Table public_data has read access for everyone
    match /public_data/{document=**} {
      allow read, write; 
    }

    // 3. Table user_data has read, write for just that authenticated user
    match /user_data/{userId} {
      allow read, update: if request.auth.uid == userId;
    }
    // (and I guess anyone should be able to create a new user too .. thats a bonus rule)
    match /user_data/{document=**} {
      allow create; 
      // and no one can delete a user
    }
  }

}

Note that the "1. No access to all tables" happens automatically.

Note that A read rule can be broken into get and list, while a write rule can be broken into create, update, and delete - https://firebase.google.com/docs/firestore/security/rules-structure

I wasn't able to figure out the Simulator that Firestore > Rules provides, I couldn't figure out what path to put into it.
But it is so easy to make the queries of the data that I ended up just testing it myself.

I'm using Flutter, so this package, & there are examples in your favourite language in the Firebase docs, eg. here is a read.