Getting started with Greengrass connectors (console)

Sign in to the AWS Secrets Manager console.

Choose Store a new secret.

Under Choose secret type, choose Other type of secret.

Under Specify the key/value pairs to be stored for this secret, on the Plaintext tab, enter your Twilio auth token. Remove all of the JSON formatting and enter only the token value.

Keep aws/secretsmanager selected for the encryption key, and then choose Next.

For Secret name, enter greengrass-TwilioAuthToken, and then choose Next.

This tutorial doesn't require rotation, so choose disable automatic rotation, and then choose Next.

On the Review page, review your settings, and then choose Store.

Next, you create a secret resource in your Greengrass group that references the secret.

In the AWS IoT console navigation pane, under Manage, expand Greengrass devices, and then choose Groups (V1).

Choose the group that you want to add the secret resource to.

On the group configuration page, choose the Resources tab, and then scroll down to the Secrets section. The Secrets section displays the secret resources that belong to the group. You can add, edit, and remove secret resources from this section.

Choose Add under the Secrets section.

On the Add a secret resource page, enter MyTwilioAuthToken for the Resource name.

For the Secret, choose greengrass-TwilioAuthToken.

In the Select labels (Optional) section, the AWSCURRENT staging label represents the latest version of the secret. This label is always included in a secret resource.

Choose Add resource.

On the group configuration page, choose Connectors, and then choose Add a connector.

On the Add connector page, choose Twilio Notifications.

Choose the version.

In the Configuration section:

Choose Add resource.

From the AWS IoT Greengrass Core SDK downloads page, download the AWS IoT Greengrass Core SDK for Python to your computer.

Unzip the downloaded package to get the SDK. The SDK is the greengrasssdk folder.

Save the following Python code function in a local file named temp_monitor.py.

import greengrasssdk
import json
import random

client = greengrasssdk.client('iot-data')

# publish to the Twilio Notifications connector through the twilio/txt topic
def function_handler(event, context):
    temp = event['temperature']
    
    # check the temperature
    # if greater than 30C, send a notification
    if temp > 30:
        data = build_request(event)
        client.publish(topic='twilio/txt', payload=json.dumps(data))
        print('published:' + str(data))
        
    print('temperature:' + str(temp))
    return

# build the Twilio request from the input data
def build_request(event):
    to_name = event['to_name']
    to_number = event['to_number']
    temp_report = 'temperature:' + str(event['temperature'])

    return {
        "request": {
            "recipient": {
                "name": to_name,
                "phone_number": to_number,
                "message": temp_report
            }
        },
        "id": "request_" + str(random.randint(1,101))
    }

Zip the following items into a file named temp_monitor_python.zip. When creating the ZIP file, include only the code and dependencies, not the containing folder.

This is your Lambda function deployment package.

First, create the Lambda function.

1. In the AWS Management Console, choose Services, and open the AWS Lambda console.

2. Choose Create function and then choose Author from scratch.

3. In the Basic information section, use the following values:

   • For Function name, enter TempMonitor.

   • For Runtime, choose Python 3.7.

   • For Permissions, keep the default setting. This creates an execution role that grants basic Lambda permissions. This role isn't used by AWS IoT Greengrass.

4. At the bottom of the page, choose Create function.

Next, register the handler and upload your Lambda function deployment package.

1. On the Code tab, under Code source, choose Upload from. From the dropdown, choose .zip file.

   

2. Choose Upload, and then choose your temp_monitor_python.zip deployment package. Then, choose Save.

3. On the Code tab for the function, under Runtime settings, choose Edit, and then enter the following values.

   • For Runtime, choose Python 3.7.

   • For Handler, enter temp_monitor.function_handler

4. Choose Save.

   Note

   The Test button on the AWS Lambda console doesn't work with this function. The AWS IoT Greengrass Core SDK doesn't contain modules that are required to run your Greengrass Lambda functions independently in the AWS Lambda console. These modules (for example, greengrass_common) are supplied to the functions after they are deployed to your Greengrass core.

Now, publish the first version of your Lambda function and create an alias for the version.

1. From the Actions menu, choose Publish new version.

2. For Version description, enter First version, and then choose Publish.

3. On the TempMonitor: 1 configuration page, from the Actions menu, choose Create alias.

4. On the Create a new alias page, use the following values:

   • For Name, enter GG_TempMonitor.

   • For Version, choose 1.

   Note

   AWS IoT Greengrass doesn't support Lambda aliases for $LATEST versions.

5. Choose Create.

On the group configuration page, choose the Lambda functions tab.

Under My Lambda functions, choose Add.

On the Add Lambda function page, choose TempMonitor for your Lambda function.

For Lambda function version, choose Alias: GG_TempMonitor.

Choose Add Lambda function.

On the group configuration page, choose the Subscriptions tab, and then choose Add Subscription.

On the Create a subscription page, configure the source and target, as follows:

1. For Source type, choose Lambda function, and then choose TempMonitor.

2. For Target type, choose Connector, and then choose Twilio Notifications.

For the Topic filter, choose twilio/txt.

Choose Create subscription.

Repeat steps 1 - 4 to create a subscription that allows AWS IoT to publish messages to the function.

1. For Source type, choose Service, and then choose IoT Cloud.

2. For Select a target, choose Lambda function, and then choose TempMonitor.

3. For Topic filter, enter temperature/input.

Repeat steps 1 - 4 to create a subscription that allows the connector to publish messages to AWS IoT.

1. For Source type, choose Connector, and then choose Twilio Notifications.

2. For Target type, choose Service, and then choose IoT Cloud.

3. For Topic filter, twilio/message/status is entered for you. This is the predefined topic that the connector publishes to.

Make sure that the AWS IoT Greengrass core is running. Run the following commands in your Raspberry Pi terminal, as needed.

1. To check whether the daemon is running:

   ps aux | grep -E 'greengrass.*daemon'

   If the output contains a root entry for /greengrass/ggc/packages/ggc-version/bin/daemon, then the daemon is running.

   Note

   The version in the path depends on the AWS IoT Greengrass Core software version that's installed on your core device.

2. To start the daemon:

   cd /greengrass/ggc/core/
   sudo ./greengrassd start

On the group configuration page, choose Deploy.

1. In the Lambda functions tab, under the System Lambda functions section, select IP detector and choose Edit.

2. In the Edit IP detector settings dialog box, select Automatically detect and override MQTT broker endpoints.

3. Choose Save.

   This enables devices to automatically acquire connectivity information for the core, such as IP address, DNS, and port number. Automatic detection is recommended, but AWS IoT Greengrass also supports manually specified endpoints. You're only prompted for the discovery method the first time that the group is deployed.

   Note

   If prompted, grant permission to create the Greengrass service role and associate it with your AWS account in the current AWS Region. This role allows AWS IoT Greengrass to access your resources in AWS services.

   The Deployments page shows the deployment timestamp, version ID, and status. When completed, the status displayed for the deployment should be Completed.

   For troubleshooting help, see Troubleshooting AWS IoT Greengrass.

On the AWS IoT console home page, choose Test.

For Subscribe to topic, use the following values, and then choose Subscribe. The Twilio Notifications connector publishes status information to this topic.

For Publish to topic, use the following values, and then choose Publish to invoke the function.

{
   "to_name": "recipient-name",
   "to_number": "recipient-phone-number",
   "temperature": 31
}

If successful, the recipient receives the text message and the console displays the success status from the output data.

Now, change the temperature in the input message to 29 and publish. Because this is less than 30, the TempMonitor function doesn't trigger a Twilio message.