• GET / : Homepage provides a form to submit a message to be published
• GET /info : Returns environment information
• GET /publish : returns message ID on successfully publishing a message

• Make sure gcloud is installed and authenticated.
• Enable Google Cloud Pub/Sub API in your Google Cloud Platform project.
• Create a topic:

       gcloud beta pubsub topics create <your-topic-name>

• Update the environment variables PUBSUB_TOPIC in appengine-web.xml.

Set the following environment variables and run using shown Maven command. You can then direct your browser to http://localhost:8080/.

export PUBSUB_TOPIC=<your-topic-name>
mvn clean appengine:run

mvn clean appengine:deploy

Direct your browser to https://pubsub.your-project-id.appspot.com