Event Source for Google Cloud Pub/Sub

This event source subscribes to messages sent to a Google Cloud Pub/Sub topic.

Prerequisite(s)

• Service Account
• Pub/Sub Topic
• Pub/Sub Subscription (optional)

Service Account

A Service Account is required to authenticate the event source and allow it to interact with Google Cloud Pub/Sub. You can create a service account by following the instructions at Creating and managing service accounts.

The service account must be granted an IAM Role with at least the following permissions:

• pubsub.subscriptions.consume
• pubsub.subscriptions.get

The following set of permissions is also required if you delegate the management of the Pub/Sub subscription to the event source. In case you prefer to manage the subscription yourself, these can be safely be omitted. More details on that topic are provided in the Pub/Sub Subscription section below.

• pubsub.subscriptions.create
• pubsub.subscriptions.delete

The predefined roles/pubsub.editor role is one example of role that is suitable for use with the TriggerMesh event source for Google Cloud Pub/Sub.

Create a key for this service account and save it. This key must be in JSON format. It is required to be able to run an instance of the Google Cloud Pub/Sub event source.

Pub/Sub Topic

If you don't already have a Pub/Sub topic to subscribe to, create one by following the instructions at Managing topics and subscriptions.

Take note of the full topic name, it is a required input to be able to run an instance of the Google Cloud Pub/Sub event source.

Pub/Sub Subscription (optional)

A subscription is required in order to allow the TriggerMesh event source for Google Cloud Pub/Sub to pull messages from a Pub/Sub topic.

This section can be skipped if you would like to let the event source manage its own subscription, which is the default behaviour. In this case, please simply ensure you granted all necessary permissions to the service account in the previous section.

If, however, you prefer messages to be pulled using a subscription which you manage yourself, please ensure that subscription is a "pull" subscription as described in the documentation page Managing topics and subscriptions.

Deploying an Instance of the Source

Open the Bridge creation screen and add a source of type Google Cloud Pub/Sub.

In the Source creation form, give a name to the event source and add the following information:

• Secret: Service account key in JSON format, as described in the previous sections.
• Topic: Full resource name of the Pub/Sub topic to subscribe to.
• Subscription ID: (optional) ID of the subscription to use for pulling messages from the Pub/Sub topic, in case you prefer to manage this subscription yourself as described in the previous sections.

After clicking the Save button, you will be taken back to the Bridge editor. Proceed to adding the remaining components to the Bridge, then submit it.

A ready status on the main Bridges page indicates that the event source is ready to consume messages from the Pub/Sub topic.

Event Types

The TriggerMesh event source for Google Cloud Pub/Sub emits events of the following type:

• com.google.cloud.pubsub.message