AWS IoT Greengrass
Developer Guide

Verify the Lambda Function Is Running on the Device

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

                    Screenshot of AWS IoT console with Test highlighted.

In 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 (more accurate).

                    Screenshot of Subscriptions.

Next, 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 running on the AWS IoT Greengrass core device continues to send MQTT messages to the hello/world topic in the AWS IoT cloud, don't stop the AWS IoT Greengrass daemon. The remaining modules are written with the assumption that it's running.