Firebase Cloud Functions

This guide shows you how to work with Google Cloud Firebase Functions locally using the Firebase Emulator Suite. This lab demonstrates a synchronous HTTPS function that retrieves a secret from Secret Manager based on user name.

Prerequisites

• Docker installed and running.
• Dev Containers extension installed (optional).

How to execute

1. Setup Environment:

   Dev Container (recommended)

   Open VS Code in the project folder and execute this command in the Command Palette:

   > Dev Containers: Reopen in Container

   Manually

   Run the setup script to install tools and dependencies:

   scripts/setup.sh

2. Start Firebase Emulators:

   firebase emulators:start

3. Run the Example:

   Python

   python main.py

   cURL

   curl "http://localhost:5001/demo-mve-firebase-functions/us-central1/get_secret?username=admin"

   REST Client
   • Install: REST Client from de VS Code Marketplace.
   • Open: Open http/get_secret.http in VS Code.
   • Run: Click Send Request above any request block.

How to debug

1. Cloud Function:

   • Ensure: Stop the Firebase Emulator before attaching the debugger (it conflicts with the debugger port).
   • Run: Launch the Debug Cloud Function (Local) configuration from the Run and Debug tab.
   • Breakpoints: Set breakpoints inside get_secret in functions/main.py.
   • Send: Trigger a request via curl or the REST Client pointing to http://localhost:8080/.

2. main.py:

   • Ensure: Stop the Firebase Emulator before attaching the debugger.
   • Run: Launch the Debug Cloud Function (Local) configuration.
   • Set: Set DEBUG_MODE=True in your .env.
   • Run: Open main.py and start the Python: Current File debugger.

3. Tests:

   • Ensure: The Firebase Emulator must be running for individual test debugging.
   • Breakpoints: Set breakpoints in tests/test_get_secret.py.
   • Run: Open the Testing tab and click the Debug Test icon next to the desired test.

How to test

• All tests: Run the automated script:

  scripts/run_tests.sh

• Individually: Use the VS Code Testing tab to run or debug specific test cases.

Firebase Emulator and tests

scripts/run_tests.sh starts its own emulator via firebase emulators:exec. Stop any running emulator before executing it.

Validate results

Open the Firebase Emulator UI and navigate to the Logs section to inspect function activity:

http://localhost:4000

Clean Up

Stop the emulators by pressing Ctrl+C in the terminal running firebase emulators:start. To remove volumes:

docker compose down -v

Next steps

• Build on this MVE with the Storage Writer project.
• Build on this MVE with the Simple ETL project.
• Build on this MVE with the No-SQL Writer project.