Quickstart for Python 3 in the App Engine Standard Environment

Region ID

The REGION_ID is an abbreviated code that Google assigns based on the region you select when you create your app. The code does not correspond to a country or province, even though some region IDs may appear similar to commonly used country and province codes. Including REGION_ID.r in App Engine URLs is optional for existing apps and will soon be required for all new apps.

To ensure a smooth transition, we are slowly updating App Engine to use region IDs. If we haven't updated your Google Cloud project yet, you won't see a region ID for your app. Since the ID is optional for existing apps, you don't need to update URLs or make other changes once the region ID is available for your existing apps.

Learn more about region IDs.

OK

Python 2.7/3 |Java 8/11 |PHP 5/7 |Ruby |Go 1.11 / 1.12+ |Node.js

This quickstart shows how to deploy a sample app on App Engine. If you want to learn about coding an app for App Engine, see Building an app.

Costs

There are no costs associated with running this guide. Running this sample app alone does not exceed your free quota.

Before you begin

Before running and deploying this quickstart, install the Cloud SDK and then set up a Cloud project for App Engine:

1. Download and install Cloud SDK:

   Download the SDK

   Note: If you already have the Cloud SDK installed, update it by running the following command:

   gcloud components update
   

2. Create a new project:

   gcloud projects create [YOUR_PROJECT_ID] --set-as-default
   

   Replace [YOUR_PROJECT_ID] with a string of characters that uniquely identifies your project. For example, my-project-24.

   Verify the project was created:

   gcloud projects describe [YOUR_PROJECT_ID]
   

   You see project details that might look like the following:

   createTime: year-month-hour
   lifecycleState: ACTIVE
   name: project-name
   parent:
   id: '433637338589'
   type: organization
   projectId: project-name-id
   projectNumber: 499227785679
   

3. Initialize your App Engine app with your project and choose its region:

   gcloud app create --project=[YOUR_PROJECT_ID]
   

   When prompted, select the region where you want your App Engine application located.

   Caution: You cannot change an app's region once it has been set.

4. Make sure billing is enabled for your project. A billing account needs to be linked to your project in order for the application to be deployed to App Engine.

   Enable billing

   Note: Running this sample app does not exceed your free quota.

5. Install the following prerequisites:

   • Download and install Git.

• Run the following command to install the gcloud component that includes the App Engine extension for Python 3:

  gcloud components install app-engine-python
  

6. Prepare your environment for Python development. It is recommended that you have the latest version of Python, pip, and other related tools installed on your system. For instructions, refer to the Python Development Environment Setup Guide.

App Engine locations

App Engine is regional, which means the infrastructure that runs your apps is located in a specific region, and Google manages it so that it is available redundantly across all of the zones within that region.

Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your apps are run. You can generally select the region nearest to your app's users, but you should consider the locations where App Engine is available as well as the locations of the other Google Cloud products and services that your app uses. Using services across multiple locations can affect your app's latency as well as its pricing.

Note: Two locations, which are called europe-west and us-central in App Engine commands and in the Google Cloud Console, are called europe-west1 and us-central1, respectively, elsewhere in Google documentation.

You cannot change an app's region after you set it.

If you already created an App Engine application, you can view its region by doing one of the following:

• Run the gcloud app describe command.

• Open the App Engine Dashboard in the Cloud Console. The region appears near the top of the page.

OK

This quickstart demonstrates a simple Python app written with the Flask web framework that can be deployed to App Engine. Although this sample uses Flask, you can use any web framework that satisfies the requirements above. Alternative frameworks include Django, Pyramid, Bottle, and web.py.

Download the Hello World app

We've created a simple Hello World app for Python 3 so you can quickly get a feel for deploying an app to the Google Cloud.

1. Clone the Hello World sample app repository to your local machine.

   git clone https://github.com/GoogleCloudPlatform/python-docs-samples
   

   Alternatively, you can download the sample as a zip file and extract it.

2. Change to the directory that contains the sample code.

   cd python-docs-samples/appengine/standard_python3/hello_world
   

Run Hello World on your local machine

To run the Hello World app on your local computer:

Mac OS / Linux

1. Create an isolated Python environment in a directory external to your project and activate it:

   python3 -m venv env
   source env/bin/activate

2. Navigate to your project directory and install dependencies:

   cd YOUR_PROJECT
   pip install  -r requirements.txt

3. Run the application:

   python main.py

4. In your web browser, enter the following address:

   http://localhost:8080

   Note: If you are using Cloud Shell, in the toolbar, click Web Preview and select Preview on port 8080 instead.

Windows

Use PowerShell to run your Python packages.

1. Locate your installation of PowerShell.
2. Right-click on the shortcut to PowerShell and start it as an administrator.
3. Create an isolated Python environment in a directory external to your project and activate it:

   python -m venv env
   env\Scripts\activate

4. Navigate to your project directory and install dependencies:

   cd YOUR_PROJECT
   pip install -r requirements.txt

5. Run the application:

   python main.py

6. In your web browser, enter the following address:

   http://localhost:8080

The Hello World message from the sample app displays on the page. In your terminal window, press Ctrl+C to exit the web server.

Deploy and run Hello World on App Engine

To deploy your app to the App Engine standard environment:

1. Deploy the Hello World app by running the following command from the standard_python3/hello_world directory:

   gcloud app deploy

   Learn about the optional flags.

   Common gcloud command flags

   • Include the --version flag to specify an ID that uniquely identifies that version of your app, otherwise one is generated for you. Example: --version [YOUR_VERSION_ID]
   • Include the --project flag to specify an alternate Cloud project ID to what you initialized as the default in the gcloud tool. Example: --project [YOUR_PROJECT_ID]

   Example:

   gcloud app deploy --version pre-prod-5 --project my-sample-app

   To learn more about deploying your app from the command line, see Testing and Deploying Your App . For a list of all the command flags, see the gcloud app deploy reference.

   OK

2. Launch your browser to view the app at https://PROJECT_ID.REGION_ID.r.appspot.com

   gcloud app browse

   where PROJECT_ID represents your Google Cloud project ID.

This time, the page that displays the Hello World message is delivered by a web server running on an App Engine instance.

Congratulations! You've deployed your first Python 3 app to App Engine standard environment!

See the following sections for information about cleaning up as well as links to possible next steps that you can take.

Clean up

To avoid incurring charges, you can delete your Cloud project to stop 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 this tutorial, 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 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

Learn the whole platform

Now that you know what it's like to develop and deploy App Engine apps, you can explore the rest of Google Cloud. You already have the Cloud SDK installed which gives you the tools to interact with products like Cloud SQL, Cloud Storage, Firestore, and more.

Learn about the App Engine standard environment

Here are some topics to help continue your learning about App Engine:

• An overview of App Engine
• Request routing
• Request handling
• Managing instances