Project: Firebase Cloud Function - User Creation with API Gateway Integration

This project defines a Firebase Cloud Function that triggers before a new user is created in Firebase Authentication. The function interacts with an external API via API Gateway to store user information and set custom claims in Firebase Authentication.

Features:

• Automatically invoked when a new user is created via Firebase Authentication.
• Fetches an identity token from Google Cloud to authenticate API requests.
• Sends user data to an external API hosted on API Gateway.
• Sets custom user claims in Firebase Authentication with the response from the external API.

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Firebase Environment Variables

You'll need the following environment variables:

• FIREBASE_API_KEY: Your Firebase API key.
• FIREBASE_AUTH_DOMAIN: Your Firebase authentication domain.

Files Overview

• index.js: Contains the logic for Firebase function.
• package.json: Includes the required dependencies such as google-auth-library, firebase-admin, and axios.

Deployment

Step 1: Install Dependencies

Install necessary packages for your project:

npm install google-auth-library axios firebase-admin

Step 2: Deploy the Firebase Cloud Function

Use the following command to deploy your Firebase Cloud Function to Google Cloud. The function will be triggered before a new user is created in Firebase Authentication. The command also passes environment variables for FIREBASE_API_KEY and FIREBASE_AUTH_DOMAIN.

gcloud functions deploy function-3 \
  --entry-point beforeCreate \
  --runtime nodejs18 \
  --trigger-event providers/firebase.auth/eventTypes/user.beforeCreate \
  --trigger-resource "projects/YOUR_PROJECT_ID" \
  --set-env-vars FIREBASE_API_KEY="your-firebase-api-key",FIREBASE_AUTH_DOMAIN="your-firebase-auth-domain"

Replace your-firebase-api-key and your-firebase-auth-domain with your actual Firebase API key and auth domain.

Step 3: Check Logs

After deployment, you can monitor the logs for your function using the following command:

gcloud functions logs read function-3

Additional CLI Commands

Test Locally (Optional)

You can test the Firebase function locally using the Firebase Emulator. First, install the Firebase tools globally if you haven't already:

npm install -g firebase-tools

Then start the Firebase Emulator:

firebase emulators:start

Delete the Cloud Function

If you need to remove the function, you can delete it with:

gcloud functions delete function-3