Fast Python Flask server deployment with GitLab + Google Cloud

Deploying an application to the cloud often requires assistance from production or DevOps engineers. GitLab’s Google Cloud integration empowers developers to handle deployments independently. In this tutorial, you’ll learn how to deploy a Python Flask server to Google Cloud in less than 10 minutes. Whether you’re a solo developer or part of a large team, this setup allows you to deploy applications efficiently.

You’ll learn how to:

• Create a new project in GitLab
• Create a Flask server utilizing main.py
• Utilize the Google Cloud integration to create a Service account
• Utilize the Google Cloud integration to create Cloud Run via a merge request
• Access your newly deployed Flask server
• Clean up your environment

Prerequisites:

• Owner access on a Google Cloud Platform project
• Working knowledge of Python
• Working knowledge of GitLab CI
• 10 minutes

Step-by-step Python Flask server deployment to Google Cloud

1. Create a new project in GitLab.

We decided to call our project “python-flask-cloud-run” for simplicity.

2. Create a flask server utilizing main.py demo.

Find the main.py demo here: https://gitlab.com/demos/applications/python-flask-cloud-run.

import os

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello_world():
    """Example Hello World route."""
    name = os.environ.get("NAME", "World")
    return f"Hello {name}!"

if __name__ == "__main__":
    app.run(debug=True, host="0.0.0.0", port=int(os.environ.get("PORT", 8080)))

3. Create a requirements.txt with the following dependencies.

Flask==3.0.3
gunicorn==22.0.0
Werkzeug==3.0.3

4. Utilizing the Google Cloud integration, create a Service account.

Navigate to Operate > Google Cloud > Create Service account.

5. Also configure the region you would like the Cloud Run instance to deploy to.

6. Utilizing the Google Cloud integration, configure Cloud Run via merge request.

7. This will open a merge request. Immediately merge this merge request.

Note: GCP_PROJECT_ID, GCP_REGION, GCP_SERVICE_ACCOUNT, GCP_SERVICE_ACCOUNT_KEY will all be automatically populated from the previous steps.

8. Voila! Check your pipeline and you will see you have successfully deployed to Google Cloud Run utilizing GitLab CI.

9. Click the Service URL to view your newly deployed Flask server.

Navigate to Operate > Environments to see a list of deployments for your environments.

By clicking on the environment called main, you’ll be able to view a complete list of deployments specific to that environment.

Next steps

To get started with developing your Flask application, try adding another endpoint. For instance, in your main.py file, you can add a /bye endpoint as shown below:

@app.route("/")
def hello_world():
    """Example Hello World route."""
    name = os.environ.get("NAME", "World")
    return f"Hello {name}!"

Push the changes to the repo, and watch the deploy-to-cloud-run job deploy the updates. Once it’s complete, go back to the Service URL and navigate to the /bye endpoint to see the new functionality in action.

Clean up

To prevent incurring charges on your Google Cloud account for the resources used in this tutorial, you can either delete the specific resources or delete the entire Google Cloud project. For detailed instructions, refer to the cleanup guide.

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