Firebase

Firebase is an app development platform built around non-relational technologies. The Firebase Wrapper supports connecting to below objects.

1. Authentication Users (read only)
2. Firestore Database Documents (read only)

Preparation

Before you can query Firebase, you need to enable the Wrappers extension and store your credentials in Postgres.

Enable Wrappers

Make sure the wrappers extension is installed on your database:

create extension if not exists wrappers with schema extensions;

Enable the Firebase Wrapper

Enable the firebase_wrapper FDW:

create foreign data wrapper firebase_wrapper
  handler firebase_fdw_handler
  validator firebase_fdw_validator;

Store your credentials (optional)

By default, Postgres stores FDW credentials inside pg_catalog.pg_foreign_server in plain text. Anyone with access to this table will be able to view these credentials. Wrappers is designed to work with Vault, which provides an additional level of security for storing credentials. We recommend using Vault to store your credentials.

-- Save your Firebase credentials in Vault and retrieve the `key_id`
insert into vault.secrets (name, secret)
values (
  'firebase',
  '{
      "type": "service_account",
      "project_id": "your_gcp_project_id",
      ...
  }'
)
returning key_id;

Connecting to Firebase

We need to provide Postgres with the credentials to connect to Firebase, and any additional options. We can do this using the create server command:

With VaultWithout Vault

create server firebase_server
  foreign data wrapper firebase_wrapper
  options (
    sa_key_id '<key_ID>', -- The Key ID from above.
    project_id '<firebase_project_id>'
);

create server firebase_server
  foreign data wrapper firebase_wrapper
   options (
     sa_key '
     {
        "type": "service_account",
        "project_id": "your_gcp_project_id",
        ...
     }
    ',
     project_id 'firebase_project_id'
   );

Create a schema

We recommend creating a schema to hold all the foreign tables:

create schema if not exists firebase;

Options

The full list of foreign table options are below:

• object - Object name in Firebase, required.

For Authenciation users, the object name is fixed to auth/users. For Firestore documents, its format is firestore/<collection_id>, note that collection id must be a full path id. For example,

• firestore/my-collection
• firestore/my-collection/my-document/another-collection

Entities

Authentication Users

This is an object representing Firebase Authentication Users.

Ref: Firebase Authentication Users

Operations

Object	Select	Insert	Update	Delete	Truncate
Authentication Users	✅	❌	❌	❌	❌

Usage

create foreign table firebase.users (
  uid text,
  email text,
  created_at timestamp,
  attrs jsonb
)
  server firebase_server
  options (
    object 'auth/users'
  );

Notes

• The attrs column contains all user attributes in JSON format
• This is a special collection with unique metadata fields

Firestore Database Documents

This is an object representing Firestore Database Documents.

Ref: Firestore Database

Operations

Object	Select	Insert	Update	Delete	Truncate
Firestore Database Documents	✅	❌	❌	❌	❌

Usage

create foreign table firebase.docs (
  name text,
  created_at timestamp,
  updated_at timestamp,
  attrs jsonb
)
  server firebase_server
  options (
    object 'firestore/user-profiles'
  );

Notes

• The name, created_at, and updated_at are automatic metadata fields on all Firestore collections
• Collection ID must be a full path ID in the format firestore/<collection_id>
• Examples of valid collection paths:
• firestore/my-collection
• firestore/my-collection/my-document/another-collection
• The attrs column contains all document attributes in JSON format

Query Pushdown Support

This FDW doesn't support query pushdown.

Limitations

This section describes important limitations and considerations when using this FDW:

• Only support read-only access to Authentication Users and Firestore Database Documents
• Default maximum row count limit is 10,000 records
• Full result sets are loaded into memory, which can impact PostgreSQL performance with large datasets
• Materialized views using these foreign tables may fail during logical backups

Examples

Some examples on how to use Firebase foreign tables.

firestore

To map a Firestore collection provide its location using the format firestore/<collection_id> as the object option as shown below.

create foreign table firebase.docs (
  name text,
  created_at timestamp,
  updated_at timestamp,
  attrs jsonb
)
  server firebase_server
  options (
    object 'firestore/user-profiles'
  );

Note that name, created_at, and updated_at, are automatic metadata fields on all Firestore collections.

auth/users

The auth/users collection is a special case with unique metadata. The following shows how to map Firebase users to PostgreSQL table.

create foreign table firebase.users (
  uid text,
  email text,
  created_at timestamp,
  attrs jsonb
)
  server firebase_server
  options (
    object 'auth/users'
  );