feat(iot-actions): add SNS publish action (aws#18839)

First-time contributor 👋 

fixes aws#17700 

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-iot-actions/README.md

@@ -30,6 +30,7 @@ Currently supported are:
 - Put records to Kinesis Data stream
 - Put records to Kinesis Data Firehose stream
 - Send messages to SQS queues
+- Publish messages on SNS topics
 
 ## Republish a message to another MQTT topic
 
@@ -256,3 +257,24 @@ const topicRule = new iot.TopicRule(this, 'TopicRule', {
   ],
 });
 ```
+
+## Publish messages on an SNS topic
+
+The code snippet below creates and AWS IoT Rule that publishes messages to an SNS topic when it is triggered:
+
+```ts
+import * as sns from '@aws-cdk/aws-sns';
+
+const topic = new sns.Topic(this, 'MyTopic');
+
+const topicRule = new iot.TopicRule(this, 'TopicRule', {
+  sql: iot.IotSql.fromStringAsVer20160323(
+    "SELECT topic(2) as device_id, year, month, day FROM 'device/+/data'",
+  ),
+  actions: [
+    new actions.SnsTopicAction(topic, {
+      messageFormat: actions.SnsActionMessageFormat.JSON, // optional property, default is SnsActionMessageFormat.RAW
+    }),
+  ],
+});
+```

packages/@aws-cdk/aws-iot-actions/lib/index.ts

@@ -8,3 +8,4 @@ export * from './kinesis-put-record-action';
 export * from './lambda-function-action';
 export * from './s3-put-object-action';
 export * from './sqs-queue-action';
+export * from './sns-topic-action';

packages/@aws-cdk/aws-iot-actions/lib/sns-topic-action.ts

@@ -0,0 +1,75 @@
+import * as iam from '@aws-cdk/aws-iam';
+import * as iot from '@aws-cdk/aws-iot';
+import * as sns from '@aws-cdk/aws-sns';
+import { CommonActionProps } from '.';
+import { singletonActionRole } from './private/role';
+
+/**
+ * SNS topic action message format options.
+ */
+export enum SnsActionMessageFormat {
+  /**
+   * RAW message format.
+   */
+  RAW = 'RAW',
+
+  /**
+   * JSON message format.
+   */
+  JSON = 'JSON'
+}
+
+/**
+ * Configuration options for the SNS topic action.
+ */
+export interface SnsTopicActionProps extends CommonActionProps {
+  /**
+   * The message format of the message to publish.
+   *
+   * SNS uses this setting to determine if the payload should be parsed and relevant platform-specific bits of the payload should be extracted.
+   * @see https://docs.aws.amazon.com/sns/latest/dg/sns-message-and-json-formats.html
+   *
+   * @default SnsActionMessageFormat.RAW
+   */
+  readonly messageFormat?: SnsActionMessageFormat;
+}
+
+/**
+ * The action to write the data from an MQTT message to an Amazon SNS topic.
+ *
+ * @see https://docs.aws.amazon.com/iot/latest/developerguide/sns-rule-action.html
+ */
+export class SnsTopicAction implements iot.IAction {
+  private readonly role?: iam.IRole;
+  private readonly topic: sns.ITopic;
+  private readonly messageFormat?: SnsActionMessageFormat;
+
+  /**
+   * @param topic The Amazon SNS topic to publish data on. Must not be a FIFO topic.
+   * @param props Properties to configure the action.
+   */
+  constructor(topic: sns.ITopic, props: SnsTopicActionProps = {}) {
+    if (topic.fifo) {
+      throw Error('IoT Rule actions cannot be used with FIFO SNS Topics, please pass a non-FIFO Topic instead');
+    }
+
+    this.topic = topic;
+    this.role = props.role;
+    this.messageFormat = props.messageFormat;
+  }
+
+  bind(rule: iot.ITopicRule): iot.ActionConfig {
+    const role = this.role ?? singletonActionRole(rule);
+    this.topic.grantPublish(role);
+
+    return {
+      configuration: {
+        sns: {
+          targetArn: this.topic.topicArn,
+          roleArn: role.roleArn,
+          messageFormat: this.messageFormat,
+        },
+      },
+    };
+  }
+}

packages/@aws-cdk/aws-iot-actions/package.json

@@ -95,6 +95,7 @@
     "@aws-cdk/aws-lambda": "0.0.0",
     "@aws-cdk/aws-logs": "0.0.0",
     "@aws-cdk/aws-s3": "0.0.0",
+    "@aws-cdk/aws-sns": "0.0.0",
     "@aws-cdk/aws-sqs": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "case": "1.6.3",
@@ -110,6 +111,7 @@
     "@aws-cdk/aws-lambda": "0.0.0",
     "@aws-cdk/aws-logs": "0.0.0",
     "@aws-cdk/aws-s3": "0.0.0",
+    "@aws-cdk/aws-sns": "0.0.0",
     "@aws-cdk/aws-sqs": "0.0.0",
     "@aws-cdk/core": "0.0.0",
     "constructs": "^3.3.69"

packages/@aws-cdk/aws-iot-actions/test/sns/integ.sns-topic-action.expected.json

@@ -0,0 +1,71 @@
+{
+  "Resources": {
+    "TopicRule40A4EA44": {
+      "Type": "AWS::IoT::TopicRule",
+      "Properties": {
+        "TopicRulePayload": {
+          "Actions": [
+            {
+              "Sns": {
+                "RoleArn": {
+                  "Fn::GetAtt": [
+                    "TopicRuleTopicRuleActionRole246C4F77",
+                    "Arn"
+                  ]
+                },
+                "TargetArn": {
+                  "Ref": "MyTopic86869434"
+                }
+              }
+            }
+          ],
+          "AwsIotSqlVersion": "2016-03-23",
+          "Sql": "SELECT topic(2) as device_id, year, month, day FROM 'device/+/data'"
+        }
+      }
+    },
+    "TopicRuleTopicRuleActionRole246C4F77": {
+      "Type": "AWS::IAM::Role",
+      "Properties": {
+        "AssumeRolePolicyDocument": {
+          "Statement": [
+            {
+              "Action": "sts:AssumeRole",
+              "Effect": "Allow",
+              "Principal": {
+                "Service": "iot.amazonaws.com"
+              }
+            }
+          ],
+          "Version": "2012-10-17"
+        }
+      }
+    },
+    "TopicRuleTopicRuleActionRoleDefaultPolicy99ADD687": {
+      "Type": "AWS::IAM::Policy",
+      "Properties": {
+        "PolicyDocument": {
+          "Statement": [
+            {
+              "Action": "sns:Publish",
+              "Effect": "Allow",
+              "Resource": {
+                "Ref": "MyTopic86869434"
+              }
+            }
+          ],
+          "Version": "2012-10-17"
+        },
+        "PolicyName": "TopicRuleTopicRuleActionRoleDefaultPolicy99ADD687",
+        "Roles": [
+          {
+            "Ref": "TopicRuleTopicRuleActionRole246C4F77"
+          }
+        ]
+      }
+    },
+    "MyTopic86869434": {
+      "Type": "AWS::SNS::Topic"
+    }
+  }
+}

packages/@aws-cdk/aws-iot-actions/test/sns/integ.sns-topic-action.ts

@@ -0,0 +1,33 @@
+/**
+ * Stack verification steps:
+ * * aws sns subscribe --topic-arn "arn:aws:sns:<region>:<account>:test-stack-MyTopic86869434-10F6E3DMK3E5P" --protocol email --notification-endpoint <email-addr>
+ * * confirm subscription from email
+ * * echo '{"message": "hello world"}' > testfile.txt
+ * * aws iot-data publish --topic device/mydevice/data --qos 1 --payload fileb://testfile.txt
+ * * verify that an email was sent from the SNS
+ * * rm testfile.txt
+ */
+/// !cdk-integ pragma:ignore-assets
+import * as iot from '@aws-cdk/aws-iot';
+import * as sns from '@aws-cdk/aws-sns';
+import * as cdk from '@aws-cdk/core';
+import * as actions from '../../lib';
+
+class TestStack extends cdk.Stack {
+  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
+    super(scope, id, props);
+
+    const topicRule = new iot.TopicRule(this, 'TopicRule', {
+      sql: iot.IotSql.fromStringAsVer20160323(
+        "SELECT topic(2) as device_id, year, month, day FROM 'device/+/data'",
+      ),
+    });
+
+    const snsTopic = new sns.Topic(this, 'MyTopic');
+    topicRule.addAction(new actions.SnsTopicAction(snsTopic));
+  }
+}
+
+const app = new cdk.App();
+new TestStack(app, 'sns-topic-action-test-stack');
+app.synth();

packages/@aws-cdk/aws-iot-actions/test/sns/sns-topic-action.test.ts

@@ -0,0 +1,103 @@
+import { Match, Template } from '@aws-cdk/assertions';
+import * as iam from '@aws-cdk/aws-iam';
+import * as iot from '@aws-cdk/aws-iot';
+import * as sns from '@aws-cdk/aws-sns';
+import * as cdk from '@aws-cdk/core';
+import * as actions from '../../lib';
+
+const SNS_TOPIC_ARN = 'arn:aws:sns::123456789012:test-topic';
+
+let stack: cdk.Stack;
+let topicRule: iot.TopicRule;
+let snsTopic: sns.ITopic;
+
+beforeEach(() => {
+  stack = new cdk.Stack();
+  topicRule = new iot.TopicRule(stack, 'MyTopicRule', {
+    sql: iot.IotSql.fromStringAsVer20160323("SELECT topic(2) as device_id FROM 'device/+/data'"),
+  });
+  snsTopic = sns.Topic.fromTopicArn(stack, 'MySnsTopic', SNS_TOPIC_ARN);
+});
+
+test('Default SNS topic action', () => {
+  // WHEN
+  topicRule.addAction(new actions.SnsTopicAction(snsTopic));
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::IoT::TopicRule', {
+    TopicRulePayload: {
+      Actions: [{
+        Sns: {
+          RoleArn: { 'Fn::GetAtt': ['MyTopicRuleTopicRuleActionRoleCE2D05DA', 'Arn'] },
+          TargetArn: SNS_TOPIC_ARN,
+        },
+      }],
+    },
+  });
+
+  Template.fromStack(stack).hasResourceProperties('AWS::IAM::Role', {
+    AssumeRolePolicyDocument: {
+      Statement: [{
+        Action: 'sts:AssumeRole',
+        Effect: 'Allow',
+        Principal: { Service: 'iot.amazonaws.com' },
+      }],
+    },
+  });
+
+  Template.fromStack(stack).hasResourceProperties('AWS::IAM::Policy', {
+    PolicyDocument: {
+      Statement: [{
+        Action: 'sns:Publish',
+        Effect: 'Allow',
+        Resource: SNS_TOPIC_ARN,
+      }],
+    },
+    Roles: [{ Ref: 'MyTopicRuleTopicRuleActionRoleCE2D05DA' }],
+  });
+});
+
+test('Can set messageFormat', () => {
+  // WHEN
+  topicRule.addAction(new actions.SnsTopicAction(snsTopic, {
+    messageFormat: actions.SnsActionMessageFormat.JSON,
+  }));
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::IoT::TopicRule', {
+    TopicRulePayload: {
+      Actions: [
+        Match.objectLike({ Sns: { MessageFormat: 'JSON' } }),
+      ],
+    },
+  });
+});
+
+test('Can set role', () => {
+  // GIVEN
+  const roleArn = 'arn:aws:iam::123456789012:role/testrole';
+  const role = iam.Role.fromRoleArn(stack, 'MyRole', roleArn);
+
+  // WHEN
+  topicRule.addAction(new actions.SnsTopicAction(snsTopic, {
+    role,
+  }));
+
+  // THEN
+  Template.fromStack(stack).hasResourceProperties('AWS::IoT::TopicRule', {
+    TopicRulePayload: {
+      Actions: [
+        Match.objectLike({ Sns: { RoleArn: roleArn } }),
+      ],
+    },
+  });
+});
+
+test('Action with FIFO topic throws error', () => {
+  // GIVEN
+  const snsFifoTopic = sns.Topic.fromTopicArn(stack, 'MyFifoTopic', `${SNS_TOPIC_ARN}.fifo`);
+
+  expect(() => {
+    topicRule.addAction(new actions.SnsTopicAction(snsFifoTopic));
+  }).toThrowError('IoT Rule actions cannot be used with FIFO SNS Topics, please pass a non-FIFO Topic instead');
+});

packages/@aws-cdk/aws-sns/lib/topic-base.ts

@@ -28,6 +28,13 @@ export interface ITopic extends IResource, notifications.INotificationRuleTarget
    */
   readonly topicName: string;
 
+  /**
+   * Whether this topic is an Amazon SNS FIFO queue. If false, this is a standard topic.
+   *
+   * @attribute
+   */
+  readonly fifo: boolean;
+
   /**
    * Subscribe some endpoint to this topic
    */
@@ -56,6 +63,8 @@ export abstract class TopicBase extends Resource implements ITopic {
 
   public abstract readonly topicName: string;
 
+  public abstract readonly fifo: boolean;
+
   /**
    * Controls automatic creation of policy objects.
    *

packages/@aws-cdk/aws-sns/lib/topic.ts

@@ -64,6 +64,7 @@ export class Topic extends TopicBase {
     class Import extends TopicBase {
       public readonly topicArn = topicArn;
       public readonly topicName = Stack.of(scope).splitArn(topicArn, ArnFormat.NO_RESOURCE_NAME).resource;
+      public readonly fifo = this.topicName.endsWith('.fifo');
       protected autoCreatePolicy: boolean = false;
     }
 
@@ -72,6 +73,7 @@ export class Topic extends TopicBase {
 
   public readonly topicArn: string;
   public readonly topicName: string;
+  public readonly fifo: boolean;
 
   protected readonly autoCreatePolicy: boolean = true;
 
@@ -110,5 +112,6 @@ export class Topic extends TopicBase {
       resource: this.physicalName,
     });
     this.topicName = this.getResourceNameAttribute(resource.attrTopicName);
+    this.fifo = props.fifo || false;
   }
 }