Quickstart: Build and deploy a Python web app to Cloud Run

Quickstart: Build and deploy a Python web app to Cloud Run

Learn how to use a single command to build and deploy a "Hello World" web application from a code sample to Google Cloud using Cloud Run.

Before you begin

1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. Make sure that billing is enabled for your Google Cloud project.

4. Install the Google Cloud CLI.

5. To initialize the gcloud CLI, run the following command:

   gcloud init

   Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.

6. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

7. Make sure that billing is enabled for your Google Cloud project.

8. Install the Google Cloud CLI.

9. To initialize the gcloud CLI, run the following command:

   gcloud init

   Note: If you installed the gcloud CLI previously, make sure you have the latest version by running gcloud components update.
10. To set the default project for your Cloud Run service:

     gcloud config set project PROJECT_ID

    Replace PROJECT_ID with your Google Cloud project ID.

11. If you are under a domain restriction organization policy restricting unauthenticated invocations for your project, you will need to access your deployed service as described under Testing private services.

12. Enable the Cloud Run Admin API and the Cloud Build API:

    gcloud services enable run.googleapis.com \
        cloudbuild.googleapis.com

    After the Cloud Run Admin API is enabled, the Compute Engine default service account is automatically created.

13. For Cloud Build to be able to build your sources, grant the Cloud Build Service Account role to the Compute Engine default service account by running the following:
    gcloud projects add-iam-policy-binding PROJECT_ID \
        --member=serviceAccount:[e-mail] \
        --role=roles/cloudbuild.builds.builder

    Replace PROJECT_NUMBER with your Google Cloud project number, and PROJECT_ID with your Google Cloud project ID. For detailed instructions on how to find your project ID, and project number, see Creating and managing projects.

    Granting the Cloud Build Service Account role to the Compute Engine default service account takes a couple of minutes to propagate.

    Note:

    The iam.automaticIamGrantsForDefaultServiceAccounts organization policy constraint prevents the Editor role from being automatically granted to default service accounts. If you created your organization after May 3, 2024, this constraint is enforced by default.

    We strongly recommend that you enforce this constraint to disable the automatic role grant. If you disable the automatic role grant, you must decide which roles to grant to the default service accounts, and then grant these roles yourself.

    If the default service account already has the Editor role, we recommend that you replace the Editor role with less permissive roles.To safely modify the service account's roles, use Policy Simulator to see the impact of the change, and then grant and revoke the appropriate roles.

Write the sample application

To write an application in Python:

1. Create a new directory named helloworld and change directory into it:

   mkdir helloworld
   cd helloworld
   

2. Create a file named main.py and paste the following code into it:

   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)))

   This code responds to requests with our "Hello World" greeting. HTTP handling is done by a Gunicorn web server in the container. When directly invoked for local use, this code creates a basic web server that listens on the port defined by the PORT environment variable.

3. Create a file named requirements.txt and paste the following code into it:

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

   This adds packages needed by the sample.

Your app is finished and ready to be deployed.

Deploy to Cloud Run from source

Important: This quickstart assumes that you have owner or editor roles in the project you are using for the quickstart. Otherwise, refer to the Cloud Run Source Developer role for the required permissions for deploying a Cloud Run resource from source.

Deploy from source automatically builds a container image from source code and deploys it.

To deploy from source:

1. In your source code directory, deploy the current folder using the following command:

   gcloud run deploy --source .

   1. When you are prompted for the service name, press Enter to accept the default name, for example helloworld.

   2. If you are prompted to enable additional APIs on the project, for example, the Artifact Registry API, respond by pressing y.

   3. When you are prompted for region: select the region of your choice, for example us-central1.

   4. If you are prompted to create a repository in the specified region, respond by pressing y.

   5. If you are prompted to allow unauthenticated invocations: respond y. You might not see this prompt if there is a domain restriction organization policy that prevents it; for more details see the Before you begin section.

   Then wait a few moments until the deployment is complete. On success, the command line displays the service URL.

2. Visit your deployed service by opening the service URL in a web browser.

Cloud Run locations

Cloud Run is regional, which means the infrastructure that runs your Cloud Run services is located in a specific region and is managed by Google to be redundantly available across all the zones within that region.

Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your Cloud Run services are run. You can generally select the region nearest to your users but you should consider the location of the other Google Cloud products that are used by your Cloud Run service. Using Google Cloud products together across multiple locations can affect your service's latency as well as cost.

Cloud Run is available in the following regions:

Subject to Tier 1 pricing

• asia-east1 (Taiwan)
• asia-northeast1 (Tokyo)
• asia-northeast2 (Osaka)
• asia-south1 (Mumbai, India)
• europe-north1 (Finland) Low CO₂
• europe-southwest1 (Madrid) Low CO₂
• europe-west1 (Belgium) Low CO₂
• europe-west4 (Netherlands) Low CO₂
• europe-west8 (Milan)
• europe-west9 (Paris) Low CO₂
• me-west1 (Tel Aviv)
• us-central1 (Iowa) Low CO₂
• us-east1 (South Carolina)
• us-east4 (Northern Virginia)
• us-east5 (Columbus)
• us-south1 (Dallas) Low CO₂
• us-west1 (Oregon) Low CO₂

Subject to Tier 2 pricing

• africa-south1 (Johannesburg)
• asia-east2 (Hong Kong)
• asia-northeast3 (Seoul, South Korea)
• asia-southeast1 (Singapore)
• asia-southeast2 (Jakarta)
• asia-south2 (Delhi, India)
• australia-southeast1 (Sydney)
• australia-southeast2 (Melbourne)
• europe-central2 (Warsaw, Poland)
• europe-west10 (Berlin) Low CO₂
• europe-west12 (Turin)
• europe-west2 (London, UK) Low CO₂
• europe-west3 (Frankfurt, Germany) Low CO₂
• europe-west6 (Zurich, Switzerland) Low CO₂
• me-central1 (Doha)
• me-central2 (Dammam)
• northamerica-northeast1 (Montreal) Low CO₂
• northamerica-northeast2 (Toronto) Low CO₂
• southamerica-east1 (Sao Paulo, Brazil) Low CO₂
• southamerica-west1 (Santiago, Chile) Low CO₂
• us-west2 (Los Angeles)
• us-west3 (Salt Lake City)
• us-west4 (Las Vegas)

If you already created a Cloud Run service, you can view the region in the Cloud Run dashboard in the Google Cloud console.

OK

Congratulations! You have just deployed a container image from source code to Cloud Run. Cloud Run automatically and horizontally scales out your container image to handle the received requests, then scales in when demand decreases. You only pay for the CPU, memory, and networking consumed during request handling.

Clean up

Remove your test project

While Cloud Run does not charge when the service is not in use, you might still be charged for storing the container image in Artifact Registry. You can delete your container image or delete your Google Cloud project to avoid incurring charges. Deleting your Google Cloud project stops billing for all the resources used within that project.

Caution: Deleting a project has the following effects:
• Everything in the project is deleted. If you used an existing project for the tasks in this document, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.
1. In the Google Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

What's next

For more information on building a container from code source and pushing to a repository, see:

• Developing Cloud Run services
• Building Containers
• Test a Cloud Run service locally
• Deploying from source code