AWS IoT Greengrass
Developer Guide

Verify the Lambda Function Is Running on the Device

  1. From the navigation pane of the AWS IoT Core console, choose Test.

                    Screenshot of AWS IoT Core console with Test highlighted.
  2. Choose Subscribe to topic, and configure the following fields:

    • For Subscription topic, enter hello/world. (Don't choose Subscribe to topic yet.)

    • For Quality of Service, choose 0.

    • For MQTT payload display, choose Display payloads as strings.


                    Screenshot of Subscriptions test page.
  3. Choose Subscribe to topic.

Assuming the Lambda function is running on your device, it publishes messages similar to the following to the hello/world topic:

                    Screenshot of message sent to the hello/world topic with message

Although the Lambda function continues to send MQTT messages to the hello/world topic, don't stop the AWS IoT Greengrass daemon. The remaining modules are written with the assumption that it's running.

You can delete the function and subscription from the group:

  • From the Lambdas page, choose the ellipsis (), and then choose Remove function.

  • From the Subscriptions page, choose the ellipsis (), and then choose Delete.

The function and subscription are removed from the core during the next group deployment.