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Google Pub/Sub Trigger

Listens to Google Pub/Sub messages (v.0.3.11)
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Overview

This node listens to messages from a specified Google Cloud Pub/Sub topic and subscription. It is useful for workflows that need to react to real-time messages published to a Pub/Sub topic, such as processing event notifications, integrating with other systems, or triggering downstream automation based on message content. For example, it can be used to listen for new user sign-up events or order updates and then process those events automatically within n8n.

Use Case Examples

  1. Listening to a Pub/Sub topic for new messages and automatically processing them in a workflow.
  2. Decoding JSON message data from Pub/Sub and using it to update a database or send notifications.

Properties

Name Meaning
Project ID Google Cloud project id where the Pub/Sub topic resides.
Topic Name of the Google Pub/Sub topic to listen to for messages.
Subscription Name of the Pub/Sub subscription for this topic and node. It will be created if it doesn't exist.
Acknowledge Messages Whether to acknowledge the received messages after processing to prevent re-delivery.
Decode JSON If enabled, automatically decode the message data from JSON format.

Output

JSON

  • id - The unique identifier of the received Pub/Sub message.
  • data - The content of the message, either as a decoded JSON object or raw string depending on the 'Decode JSON' setting.
  • attributes - Additional attributes associated with the Pub/Sub message.

Dependencies

  • Google Cloud Pub/Sub API
  • Google Auth Library

Troubleshooting

  • Ensure that the provided Google Cloud project ID, topic, and subscription names are correct and that the service account credentials have the necessary Pub/Sub permissions.
  • If messages are not received, verify that the topic and subscription exist or allow the node to create them automatically.
  • If JSON decoding fails, check that the message data is valid JSON and that 'Decode JSON' is enabled only when appropriate.
  • Timeout error during manual trigger execution indicates no message was received within 30 seconds; this timeout does not apply to active workflows which listen indefinitely.

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