Firebase
Firebase is an app development platform built around non-relational technologies. The Firebase Wrapper supports connecting to below objects.
- Authentication Users (read only)
- Firestore Database Documents (read only)
Restoring a logical backup of a database with a materialized view using a foreign table can fail. For this reason, either do not use foreign tables in materialized views or use them in databases with physical backups enabled.
Preparation
Before you get started, make sure the wrappers extension is installed on your database:
_10create extension if not exists wrappers with schema extensions;
and then create the foreign data wrapper:
_10create foreign data wrapper firebase_wrapper_10 handler firebase_fdw_handler_10 validator firebase_fdw_validator;
Secure your credentials (optional)
By default, Postgres stores FDW credentials inide 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.
_11-- Save your Firebase credentials in Vault and retrieve the `key_id`_11insert into vault.secrets (name, secret)_11values (_11 'firebase',_11 '{_11 "type": "service_account",_11 "project_id": "your_gcp_project_id",_11 ..._11 }'_11)_11returning 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:
_10create server firebase_server_10 foreign data wrapper firebase_wrapper_10 options (_10 sa_key_id '<key_ID>', -- The Key ID from above._10 project_id '<firebase_project_id>'_10);
Creating Foreign Tables
The Firebase Wrapper supports reading data from below Firebase's objects:
| Firebase | Select | Insert | Update | Delete | Truncate |
|---|---|---|---|---|---|
| Authentication Users | ✅ | ❌ | ❌ | ❌ | ❌ |
| Firestore Database Documents | ✅ | ❌ | ❌ | ❌ | ❌ |
For example:
_10create foreign table firebase_users (_10 uid text,_10 email text,_10 created_at timestamp,_10 attrs jsonb_10)_10 server firebase_server_10 options (_10 object 'auth/users'_10 );
Note there is a meta column attrs in the foreign table, which contains all the returned data from Firebase as json format.
Foreign table 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 isfirestore/<collection_id>, note that collection id must be a full path id. For example,firestore/my-collectionfirestore/my-collection/my-document/another-collection
Query Pushdown Support
This FDW doesn't support query pushdown.
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.
_10create foreign table firebase_docs (_10 name text,_10 created_at timestamp,_10 updated_at timestamp,_10 attrs jsonb_10)_10 server firebase_server_10 options (_10 object 'firestore/user-profiles'_10 );
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.
_10create foreign table firebase_users (_10 uid text,_10 email text,_10 created_at timestamp,_10 attrs jsonb_10)_10 server firebase_server_10 options (_10 object 'auth/users'_10 );