NoSQL Writer

This guide shows you how to work with Google Cloud Run and Firestore locally using the Firebase Emulator Suite and Python. This lab demonstrates how to create a containerized service that registers patients in Firestore.

Prerequisites

• Docker installed and running.
• Dev Containers extension installed (optional).
• Without Dev Container, you also need:
  • Python 3.12+.
  • Node.js.
  • Java JDK.
  • Google Cloud CLI.
  • Minikube.
  • Firebase CLI (npm install -g firebase-tools).

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

   Cloud Code (Minikube)

   Install dependencies:

   uv sync

2. Start Firebase Emulators:

   firebase emulators:start

3. Run the Service:

   Docker (Dev Container)

   Open a new terminal and build and run the service container:

   docker build -t patient-service ./app
   docker run --rm -p 8080:8080 --net=host -e FIRESTORE_EMULATOR_HOST=localhost:8081 patient-service

   Cloud Code (Minikube)
   1. Open the Cloud Code panel in the VS Code activity bar.
   2. Expand Cloud Run.
   3. Click Run on Cloud Run Emulator (play icon).

      First run downloads and sets up Minikube — this takes 10–15 minutes.

4. Run the Example:

   Python

   python main.py

   cURL

   curl -v -X POST http://localhost:8080 \
        -H "Content-Type: application/json" \
        -d '{"name": "Test", "surname": "User", "dni": "12345678X"}'

Docker path limitations

The Docker path does not support hot reload or Knative behavior simulation. Use Cloud Code (Minikube) for a production-like environment. If Google Cloud login prompts appear, select No/Cancel — the lab runs 100% locally.

Validate results

Open the Firebase Emulator UI and navigate to Firestore to verify the registered patient documents:

http://localhost:4000

Clean Up

Docker (Dev Container)

docker stop patient-service
pkill -f firebase

Cloud Code (Minikube)

Click the Stop (red square) button in VS Code, or run:

minikube stop
pkill -f firebase

Troubleshooting

Issue	Solution
Connection Refused (Firestore)	Ensure firebase emulators:start is running. On Linux with Minikube, change FIRESTORE_EMULATOR_HOST to host.minikube.internal:8081 in .vscode/launch.json.
Persistent Google Cloud login prompts	Ensure .vscode/settings.json includes "cloudcode.useGcloudAuthSkaffold": false and select No/Cancel when prompted.
Firebase Emulator fails to start	Ensure Node.js and Java JDK are installed. Check ports 8081 and 4000 are available.

Next steps

• See the Azure equivalent project.
• Dive into the Firebase Cloud Functions Lab.