fix(iot): unable to add the same lambda function to two TopicRule Actions

packages/@aws-cdk/aws-iot-actions/lib/lambda-function-action.ts

@@ -1,6 +1,7 @@
 import * as iam from '@aws-cdk/aws-iam';
 import * as iot from '@aws-cdk/aws-iot';
 import * as lambda from '@aws-cdk/aws-lambda';
+import { Names } from '@aws-cdk/core';
 
 /**
  * The action to invoke an AWS Lambda function, passing in an MQTT message.
@@ -12,7 +13,7 @@ export class LambdaFunctionAction implements iot.IAction {
   constructor(private readonly func: lambda.IFunction) {}
 
   bind(topicRule: iot.ITopicRule): iot.ActionConfig {
-    this.func.addPermission('invokedByAwsIotRule', {
+    this.func.addPermission(`${Names.nodeUniqueId(topicRule.node)}:Permission`, {
       action: 'lambda:InvokeFunction',
       principal: new iam.ServicePrincipal('iot.amazonaws.com'),
       sourceAccount: topicRule.env.account,

packages/@aws-cdk/aws-iot-actions/test/lambda/integ.lambda-function-action.expected.json

@@ -50,7 +50,7 @@
         "MyFunctionServiceRole3C357FF2"
       ]
     },
-    "MyFunctioninvokedByAwsIotRule5581F304": {
+    "MyFunctionteststackTopicRule1CB8242FPermission62920382": {
       "Type": "AWS::Lambda::Permission",
       "Properties": {
         "Action": "lambda:InvokeFunction",

packages/@aws-cdk/aws-iot-actions/test/lambda/lambda-function-action.test.ts

@@ -55,3 +55,26 @@ test('create a topic rule with lambda action and a lambda permission to be invok
     },
   });
 });
+
+test('When two topic rules have the same action, it should not throw a error', () => {
+  // GIVEN
+  const stack = new cdk.Stack();
+  const func = new lambda.Function(stack, 'MyFunction', {
+    runtime: lambda.Runtime.NODEJS_14_X,
+    handler: 'index.handler',
+    code: lambda.Code.fromInline('console.log("foo")'),
+  });
+  const action = new actions.LambdaFunctionAction(func);
+
+  // WHEN
+  new iot.TopicRule(stack, 'MyTopicRule1', {
+    sql: iot.IotSql.fromStringAsVer20160323("SELECT topic(2) as device_id FROM 'device/+/data'"),
+    actions: [action],
+  });
+
+  // THEN
+  expect(() => new iot.TopicRule(stack, 'MyTopicRule2', {
+    sql: iot.IotSql.fromStringAsVer20160323("SELECT topic(2) as device_id FROM 'device/+/data'"),
+    actions: [action],
+  })).not.toThrow();
+});