This quickstart shows you how to create a small App Engine application that displays a short message.
Download the Hello World app
We've created a simple Hello World app for Python so you can quickly get a feel for deploying an app to Google Cloud Platform. Follow these steps to download Hello World to your local machine.
Clone the Hello World sample app repository to your local machine:
git clone https://github.com/GoogleCloudPlatform/python-docs-samples
Then go to the directory that contains the sample code:
Alternatively, you can download the sample as a zip file and extract it.
Test the application
Test the application using the development web server, which is included with the App Engine SDK.
From within the sample directory, start the development server with the following command using Google Cloud SDK Shell:
The development server is now running, listening for requests on port 8080.
Caution: If you did not create symlinks for
dev_appserver.pywhen installing the App Engine SDK, you may need to specify the full path to
Visit http://localhost:8080/ in your web browser to see the app in action.
For more information about running the development web server, see the Python Development Server reference.
Make a change
You can leave the web server running while you develop your application. The web server watches for changes in your source files and reloads them if necessary.
- Try it now: Leave the web server running, then edit
main.pyat python-doc-samples\appengine\standard\hello_world to change
Hello, World!to something else.
- Reload http://localhost:8080/ to see the results.
Deploy your app
To deploy your app to App Engine, you will need to register a project to create your project ID, which will determine the URL for the app.
- In the Cloud Platform Console, go to the Projects page and select or create a new project.GO TO THE PROJECTS PAGE
- Note the project ID that you created above.
Upload your application to Google App Engine by invoking the following command. This opens a browser window for you to sign in using your Google account. You'll be providing the project ID as the argument for
-A. Use the
-Vargument to specify a version name.
appcfg.py -A <YOUR_PROJECT_ID> -V v1 update .
Your app is now deployed and ready to serve traffic at
You have completed this quickstart.
The full URL for your application is
http://<YOUR_PROJECT_ID>.appspot.com/. Optionally, you can purchase and use a top-level domain name for your app, or use one that you have already registered.
To avoid incurring charges to your Google Cloud Platform account for the resources used in this quickstart:
- Go to the Cloud Platform Console.
- In the list of projects, select the project that you want to shut down.
- In the prompt, type your project ID to confirm the deletion.
- Click Shut down to schedule your project for deletion.
Use a custom domain
You can serve your App Engine app using your own custom domain instead of
appspot.com. For more information, see Using Custom Domains and SSL.
Hello World code review
Hello World is the simplest possible App Engine app: it contains only one Python module, has only one version, and all of the code is located within the app's root directory. This section describes each of the app files in detail.
This Python script responds to a request with an HTTP header and the message
import webapp2 class MainPage(webapp2.RequestHandler): def get(self): self.response.headers['Content-Type'] \= 'text/plain' self.response.write('Hello, World!') app \= webapp2.WSGIApplication([ ('/', MainPage), ], debug\=True)
app.yaml configuration file defines several options for the app, and describes which handler scripts should be used for which URLs.
runtime: python27 api_version: 1 threadsafe: true handlers: - url: /.* script: main.app
From top to bottom, this configuration file says the following about this application:
- This code runs in the
python27runtime environment, API version
1. Additional runtime environments and languages may be supported in the future.
- This application is
threadsafeso the same instance can handle several simultaneous requests. Threadsafe is an advanced feature and can result in erratic behavior if your application is not specifically designed to be threadsafe.
- Every request to a URL whose path matches the regular expression
/.*(all URLs) should be handled by the
appobject in the
Learn the whole platform
Now that you know what it's like to develop and deploy App Engine apps, you can stretch out and see the rest of Google Cloud Platform. For a guided walkthrough that teaches you how to create an application that uses the entire platform, not just App Engine, check out our Creating a Guestbookquickstart in which you expand this simple application to become a fully-fledged Guestbook application that lets authenticated Google accounts post messages to a public page.