This sample demonstrates how to use Google Cloud Pub/Sub and Google Translate from Google App Engine standard environment.

The home page of this application provides a form to publish messages using Google/Cloud PubSub (though publishing in local development is currently not supported). The application then receives these published messages over a push subscription endpoint, translates it from a source language into a target language, and finally stores in Google Cloud Datastore.

The home page also provides a view of the most recently translated messages persisted in storage.

Copy the sample apps to your local machine, and cd to the translate-pubsub directory:

git clone https://github.com/GoogleCloudPlatform/java-docs-samples
cd java-docs-samples/appengine-java8/translate-pubsub

• Make sure gcloud is installed and initialized:

   gcloud init

• If this is the first time you are creating an App Engine project

   gcloud app create

• For local development, set up authentication

• Enable Pub/Sub and Translate APIs

• Choose a topic name and verification token.

  • Set the following environment variables. The verification token is used to ensure that the end point only handles requests that are sent matching the verification token. You can use uuidgen on MacOS X, Windows, and Linux to generate a unique verification token. There are also online tools to generate UUIDs, such as uuidgenerator.net.

export PUBSUB_TOPIC=<your-topic-name>
export PUBSUB_VERIFICATION_TOKEN=<your-verification-token>

• Create a topic

gcloud pubsub topics create $PUBSUB_TOPIC

• Create a push subscription, to send messages to a Google Cloud Project URL such as https://.appspot.com/push.

gcloud pubsub subscriptions create <your-subscription-name> \
  --topic $PUBSUB_TOPIC \
  --push-endpoint \
  https://<your-project-id>.appspot.com/pubsub/push?token=$PUBSUB_VERIFICATION_TOKEN \
  --ack-deadline 30

Run using shown Maven command. You can then direct your browser to http://localhost:8080/ to see translated messages created in the following step.

mvn appengine:run

   curl -H "Content-Type: application/json" -i --data @sample_message.json \
   "localhost:8080/pubsub/push?token=$PUBSUB_VERIFICATION_TOKEN"

Update the environment variables PUBSUB_TOPIC and PUBSUB_VERIFICATION_TOKEN in appengine-web.xml, then:

   mvn appengine:deploy

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