AWS IoT Greengrass Version 1 entered the extended life phase on June 30, 2023. For more information, see the AWS IoT Greengrass V1 maintenance policy. After this date, AWS IoT Greengrass V1 won't release updates that provide features, enhancements, bug fixes, or security patches. Devices that run on AWS IoT Greengrass V1 won't be disrupted and will continue to operate and to connect to the cloud. We strongly recommend that you migrate to AWS IoT Greengrass Version 2, which adds significant new features and support for additional platforms.

SNS connector

The SNS connector publishes messages to an Amazon SNS topic. This enables web servers, email addresses, and other message subscribers to respond to events in the Greengrass group.

This connector receives SNS message information on an MQTT topic, and then sends the message to a specified SNS topic. You can optionally use custom Lambda functions to implement filtering or formatting logic on messages before they are published to this connector.

This connector has the following versions.

For information about version changes, see the Changelog.

Requirements

This connector has the following requirements:

Version 3 - 4

• AWS IoT Greengrass Core software v1.9.3 or later.

• Python version 3.7 or 3.8 installed on the core device and added to the PATH environment variable.

  Note

  To use Python 3.8, run the following command to create a symbolic link from the the default Python 3.7 installation folder to the installed Python 3.8 binaries.

  sudo ln -s path-to-python-3.8/python3.8 /usr/bin/python3.7

  This configures your device to meet the Python requirement for AWS IoT Greengrass.

• A configured SNS topic. For more information, see Creating an Amazon SNS topic in the Amazon Simple Notification Service Developer Guide.

• The Greengrass group role configured to allow the sns:Publish action on the target Amazon SNStopic, as shown in the following example IAM policy.

  {
      "Version":"2012-10-17",
      "Statement":[
          {
              "Sid":"Stmt1528133056761",
              "Action":[
                  "sns:Publish"
              ],
              "Effect":"Allow",
              "Resource":[
                  "arn:aws:sns:region:account-id:topic-name"
              ]
          }
      ]
   }

  This connector allows you to dynamically override the default topic in the input message payload. If your implementation uses this feature, the IAM policy must allow sns:Publish permission on all target topics. You can grant granular or conditional access to resources (for example, by using a wildcard * naming scheme).

  For the group role requirement, you must configure the role to grant the required permissions and make sure the role has been added to the group. For more information, see Managing the Greengrass group role (console) or Managing the Greengrass group role (CLI).

Versions 1 - 2

• AWS IoT Greengrass Core software v1.7 or later.

• Python version 2.7 installed on the core device and added to the PATH environment variable.

• A configured SNS topic. For more information, see Creating an Amazon SNS topic in the Amazon Simple Notification Service Developer Guide.

• The Greengrass group role configured to allow the sns:Publish action on the target Amazon SNStopic, as shown in the following example IAM policy.

  {
      "Version":"2012-10-17",
      "Statement":[
          {
              "Sid":"Stmt1528133056761",
              "Action":[
                  "sns:Publish"
              ],
              "Effect":"Allow",
              "Resource":[
                  "arn:aws:sns:region:account-id:topic-name"
              ]
          }
      ]
   }

  This connector allows you to dynamically override the default topic in the input message payload. If your implementation uses this feature, the IAM policy must allow sns:Publish permission on all target topics. You can grant granular or conditional access to resources (for example, by using a wildcard * naming scheme).

  For the group role requirement, you must configure the role to grant the required permissions and make sure the role has been added to the group. For more information, see Managing the Greengrass group role (console) or Managing the Greengrass group role (CLI).

Connector Parameters

This connector provides the following parameters:

Version 4

DefaultSNSArn

The ARN of the default SNS topic to publish messages to. The destination topic can be overridden by the sns_topic_arn property in the input message payload.

Note

The group role must allow sns:Publish permission to all target topics. For more information, see Requirements.

Display name in the AWS IoT console: Default SNS topic ARN

Required: true

Type: string

Valid pattern: arn:aws:sns:([a-z]{2}-[a-z]+-\d{1}):(\d{12}):([a-zA-Z0-9-_]+)$

IsolationMode

The containerization mode for this connector. The default is GreengrassContainer, which means that the connector runs in an isolated runtime environment inside the AWS IoT Greengrass container.

Note

The default containerization setting for the group does not apply to connectors.

Display name in the AWS IoT console: Container isolation mode

Required: false

Type: string

Valid values: GreengrassContainer or NoContainer

Valid pattern: ^NoContainer$|^GreengrassContainer$

Versions 1 - 3

DefaultSNSArn

The ARN of the default SNS topic to publish messages to. The destination topic can be overridden by the sns_topic_arn property in the input message payload.

Note

The group role must allow sns:Publish permission to all target topics. For more information, see Requirements.

Display name in the AWS IoT console: Default SNS topic ARN

Required: true

Type: string

Valid pattern: arn:aws:sns:([a-z]{2}-[a-z]+-\d{1}):(\d{12}):([a-zA-Z0-9-_]+)$

Create Connector Example (AWS CLI)

The following CLI command creates a ConnectorDefinition with an initial version that contains the SNS connector.

aws greengrass create-connector-definition --name MyGreengrassConnectors --initial-version '{
    "Connectors": [
        {
            "Id": "MySNSConnector",
            "ConnectorArn": "arn:aws:greengrass:region::/connectors/SNS/versions/4",
            "Parameters": {
                "DefaultSNSArn": "arn:aws:sns:region:account-id:topic-name",
                "IsolationMode" : "GreengrassContainer"
            }
        }
    ]
}'

In the AWS IoT Greengrass console, you can add a connector from the group's Connectors page. For more information, see Getting started with Greengrass connectors (console).

Input data

This connector accepts SNS message information on an MQTT topic, and then publishes the message as is to the target SNS topic. Input messages must be in JSON format.

Output data

This connector publishes status information as output data on an MQTT topic.

Usage Example

Use the following high-level steps to set up an example Python 3.7 Lambda function that you can use to try out the connector.

Example

The following example Lambda function sends an input message to the connector.

import greengrasssdk
import time
import json

iot_client = greengrasssdk.client('iot-data')
send_topic = 'sns/message'

def create_request_with_all_fields():
    return  {
        "request": {
            "message": "Message from SNS Connector Test"
        },
        "id" : "req_123"
    }

def publish_basic_message():
    messageToPublish = create_request_with_all_fields()
    print("Message To Publish: ", messageToPublish)
    iot_client.publish(topic=send_topic,
        payload=json.dumps(messageToPublish))

publish_basic_message()

def lambda_handler(event, context):
    return

Licenses

The SNS connector includes the following third-party software/licensing:

This connector is released under the Greengrass Core Software License Agreement.

Changelog

The following table describes the changes in each version of the connector.

A Greengrass group can contain only one version of the connector at a time. For information about upgrading a connector version, see Upgrading connector versions.

See also