Tracing @google-cloud/pubsub consumers can be done in two methods:

1. Auto-tracing using the environment variable.
2. Calling the SDK.

Calling the SDK is simple, and should be done in your main js file where the consumer is being initialized:

const epsagon = require('epsagon-frameworks');

epsagon.init({
  token: 'epsagon-token',
  appName: 'app-name-stage',
  metadataOnly: false,
});

Tagging traces or setting custom errors can be by:

await consumer.run({
  eachMessage: async ({ topic, partition, message }) => {
    message.epsagon.label('key', 'value');
    message.epsagon.setError(Error('My custom error'));
  },
})