This folder contains functionally identical apps that illustrate use of the App Engine Deferred service.

The apps are written using three different web frameworks: Flask, Django, and the App Engine bundled services wsgi functionality.

When run in App Engine, a GET request to /counter/get will display the current value of the counter. A GET request to /counter/increment will cause the counter to be incremented via the Deferred service, once immediately, once after 10 seconds, and once after 20 seconds.

Deploy this app to App Engine via gcloud app deploy. More about App Engine Bundled Deferred API at: https://cloud.google.com/appengine/docs/standard/python3/services/deferred#python-3-flask

The App Engine bundled services can be used from within properly configured App Engine applications, so testing these apps requires deploying them to App Engine.

Each version of the app includes a test program that will:

1. Launch a new version of the app to App Engine without routing network requests to it.
2. Interact with the launched app via web requests to the URL of the specific version that was launched.
3. Delete the newly launched app version. This is possible because it did not have requests routed to it.

Since each test uses a separate version and addresses test messages and web requests to that version, multiple tests can run simultaneously without interfering with each other.