Verify the Lambda function is running on the core device - Amazon IoT Greengrass
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Amazon IoT Greengrass Version 1 no longer receives feature updates, and will receive only security patches and bug fixes until June 30, 2023. For more information, see the Amazon IoT Greengrass V1 maintenance policy. We strongly recommend that you migrate to Amazon IoT Greengrass Version 2, which adds significant new features and support for additional platforms.

Verify the Lambda function is running on the core device

  1. From the navigation pane of the Amazon IoT console, under Test, choose MQTT test client.

  2. Choose the Subscribe to topic tab.

  3. Enter hello/world into the Topic filter and expand the Additional configuration.

  4. Enter the information listed in each of the following fields:

    • For Quality of Service, choose 0.

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

     

  5. Choose Subscribe.

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
                        highlighted.

Although the Lambda function continues to send MQTT messages to the hello/world topic, don't stop the Amazon 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:

  • On the groups configuration page, under the Lambda functions tab, select the Lambda function you want to remove and choose Remove.

  • On the groups configuration page, under the Subscriptions tab, choose the subscription, and then choose Delete.

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