App Engine Dev Tips #5 : Make _ah/admin your friend

December 2017: Please note that this post has not been updated for a while and there could be differences in terms of commands, screenshots and problems in running the code.

Before you deploy your application to the App Engine Cloud, it is important that you test out your application locally.

The App Engine team has given you a nice tool that helps you to test out things locally to some extent. Assuming that your application is running, you can access this Administrative tool locally via the _ah/admin endpoint. For e.g. http://localhost:8888/_ah/admin right in your browser.

It will bring up a web application (a screenshot from my local environment is shown below):

It helps you do a lot of things locally.

• Datastore Viewer : This will let you inspect all the entities that are present in your application. You can also select one of the entities and click on List Entities. This will show all the rows (records). You can even delete them. Ability to Edit is not there here. It is there in the Admin Console on the Cloud App Engine instance.
• Another feature I have found very useful in local environment is XMPP and Inbound Mail. You can easily test out sending dummy XMPP Messages and Email messages to your application. If you were figuring out how to send messages to your local environment to help you verify and/or do debugging, this is the way.

In short, the _ah/admin is critical to your local development. Make it your friend.