Programming Google App Engine

Chapter 12. Bulk Data Operations and Remote Access

The datastore is designed for retrieving and processing data at a rate suitable for interactive web applications. A single request may need to update a few entities, or query for and retrieve several dozen. Larger amounts of work triggered by interactive actions are not typically expected to be performed within a single web request. (App Engine’s facility for such work, task queues, is discussed in Chapter 13.) User-initiated actions tend to fit into this model of short requests.

Administrative actions, such as one-off chores performed by the application’s maintainers and staff, sometimes follow a different model. You may need to create or update thousands of entities from a datafile, or download the complete contents of the datastore for archival or offline testing. A change to a data model in a new version of the software may require modifying millions of entities to match before the software can be deployed.

You could build features into the application to do these things, and that may be appropriate for routine maintenance tasks. But App Engine has a feature that makes it easy to do ad hoc work with a live application, driven from your own computer: a remote access API.

With the remote access API, utilities running on your computer can call the live application’s services, such as the datastore, using the same APIs and libraries that the application uses. Each service call becomes a web request that is processed by a request handler. ...