Lab: An API on the Functions Framework with the Firestore emulator

What you will learn in this TP

• Use the Firestore emulator
• Write a function with the Functions Framework
• Prepare the container for Cloud Run

Introduction #

What you will learn in this section

• Use the Firestore emulator
• Write a function with the Functions Framework
• Prepare the container for Cloud Run

Context. A product team wants a serverless user profile API. You build it entirely locally before any deployment.

Prerequisites: Docker, Python 3 and the Google Cloud SDK (gcloud with emulator components); no Google Cloud project or billing needed  ·  Estimated time: 50 min

An API that creates, reads and lists profiles in Firestore, run locally and in a container.

Hands-on #

Guided steps, with their solution.

1. 1. Start the Firestore emulator

   Why? FIRESTORE_EMULATOR_HOST redirects the Python client.

   Start the emulator and install the libraries.

2. 2. Write the function

   Why? The same code runs on Cloud Run functions unchanged.

   Create main.py: POST creates a profile, GET with ?id= reads it, GET without parameter lists profiles.

3. 3. Run and test

   Why? functions-framework simulates the Google runtime.

   Run the function on port 8080, create a profile, read it back and list.

4. 4. Containerise for Cloud Run

   Why? Cloud Run runs any container listening on $PORT.

   Write a Dockerfile, build the image and run it connected to the emulator.

Difficulty level : ●●●○○ (3/5)