feat(iot): Add IAction

This change adds `IAction` to aws-iot for preparing to implemamt AWS IoT Rule
actions.

packages/@aws-cdk/aws-iot/lib/action.ts

@@ -0,0 +1,24 @@
+import { CfnTopicRule } from './iot.generated';
+import { ITopicRule } from './topic-rule';
+
+/**
+ * An abstract action for TopicRule.
+ */
+export interface IAction {
+  /**
+   * Returns the topic rule action specification.
+   *
+   * @param rule The TopicRule that would trigger this action.
+   */
+  bind(rule: ITopicRule): ActionConfig;
+}
+
+/**
+ * Properties for an topic rule action
+ */
+export interface ActionConfig {
+  /**
+   * The configuration for this action.
+   */
+  readonly configuration: CfnTopicRule.ActionProperty;
+}

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

@@ -1,3 +1,4 @@
+export * from './action';
 export * from './iot-sql';
 export * from './topic-rule';
 

packages/@aws-cdk/aws-iot/lib/topic-rule.ts

@@ -1,5 +1,6 @@
-import { ArnFormat, Resource, Stack, IResource } from '@aws-cdk/core';
+import { ArnFormat, Resource, Stack, IResource, Lazy } from '@aws-cdk/core';
 import { Construct } from 'constructs';
+import { IAction } from './action';
 import { IotSql } from './iot-sql';
 import { CfnTopicRule } from './iot.generated';
 
@@ -33,6 +34,13 @@ export interface TopicRuleProps {
    */
   readonly topicRuleName?: string;
 
+  /**
+   * The actions associated with the rule.
+   *
+   * @default No actions will be perform
+   */
+  readonly actions?: Array<IAction>;
+
   /**
    * A simplified SQL syntax to filter messages received on an MQTT topic and push the data elsewhere.
    *
@@ -80,6 +88,8 @@ export class TopicRule extends Resource implements ITopicRule {
    */
   public readonly topicRuleName: string;
 
+  private readonly actions = new Array<CfnTopicRule.ActionProperty>();
+
   constructor(scope: Construct, id: string, props: TopicRuleProps) {
     super(scope, id, {
       physicalName: props.topicRuleName,
@@ -90,7 +100,7 @@ export class TopicRule extends Resource implements ITopicRule {
     const resource = new CfnTopicRule(this, 'Resource', {
       ruleName: this.physicalName,
       topicRulePayload: {
-        actions: [],
+        actions: Lazy.any({ produce: () => this.actions }),
         awsIotSqlVersion: sqlConfig.awsIotSqlVersion,
         sql: sqlConfig.sql,
       },
@@ -102,5 +112,28 @@ export class TopicRule extends Resource implements ITopicRule {
       resourceName: this.physicalName,
     });
     this.topicRuleName = this.getResourceNameAttribute(resource.ref);
+
+    props.actions?.forEach(action => {
+      this.addAction(action);
+    });
+  }
+
+  /**
+   * Add a action to the rule.
+   *
+   * @param action the action to associate with the rule.
+   */
+  public addAction(action: IAction): void {
+    const { configuration } = action.bind(this);
+
+    const keys = Object.keys(configuration);
+    if (keys.length === 0) {
+      throw new Error('An action property cannot be an empty object.');
+    }
+    if (keys.length >= 2) {
+      throw new Error(`An action property cannot have multiple keys, received: ${keys}`);
+    }
+
+    this.actions.push(configuration);
   }
 }

packages/@aws-cdk/aws-iot/test/topic-rule.test.ts

@@ -100,6 +100,119 @@ test.each([
   }).toThrow('IoT SQL string cannot be empty');
 });
 
+test('can set actions', () => {
+  const stack = new cdk.Stack();
+
+  const action1: iot.IAction = {
+    bind: () => ({
+      configuration: {
+        http: { url: 'http://example.com' },
+      },
+    }),
+  };
+  const action2: iot.IAction = {
+    bind: () => ({
+      configuration: {
+        lambda: { functionArn: 'test-functionArn' },
+      },
+    }),
+  };
+
+  new iot.TopicRule(stack, 'MyTopicRule', {
+    sql: iot.IotSql.fromStringAsVer20151008("SELECT topic(2) as device_id, temperature FROM 'device/+/data'"),
+    actions: [action1, action2],
+  });
+
+  Template.fromStack(stack).hasResourceProperties('AWS::IoT::TopicRule', {
+    TopicRulePayload: {
+      Actions: [
+        {
+          Http: { Url: 'http://example.com' },
+        },
+        {
+          Lambda: { FunctionArn: 'test-functionArn' },
+        },
+      ],
+      Sql: "SELECT topic(2) as device_id, temperature FROM 'device/+/data'",
+    },
+  });
+});
+
+test('can add an action', () => {
+  const stack = new cdk.Stack();
+
+  const topicRule = new iot.TopicRule(stack, 'MyTopicRule', {
+    sql: iot.IotSql.fromStringAsVer20151008("SELECT topic(2) as device_id, temperature FROM 'device/+/data'"),
+  });
+  topicRule.addAction({
+    bind: () => ({
+      configuration: {
+        http: { url: 'http://example.com' },
+      },
+    }),
+  });
+  topicRule.addAction({
+    bind: () => ({
+      configuration: {
+        lambda: { functionArn: 'test-functionArn' },
+      },
+    }),
+  });
+
+  Template.fromStack(stack).hasResourceProperties('AWS::IoT::TopicRule', {
+    TopicRulePayload: {
+      Actions: [
+        {
+          Http: { Url: 'http://example.com' },
+        },
+        {
+          Lambda: { FunctionArn: 'test-functionArn' },
+        },
+      ],
+      Sql: "SELECT topic(2) as device_id, temperature FROM 'device/+/data'",
+    },
+  });
+});
+
+test('cannot add an action as empty object', () => {
+  const stack = new cdk.Stack();
+  const topicRule = new iot.TopicRule(stack, 'MyTopicRule', {
+    sql: iot.IotSql.fromStringAsVer20151008("SELECT topic(2) as device_id, temperature FROM 'device/+/data'"),
+  });
+
+  const emptyKeysAction: iot.IAction = {
+    bind: () => ({
+      configuration: {},
+    }),
+  };
+
+  expect(() => {
+    topicRule.addAction(emptyKeysAction);
+  }).toThrow('An action property cannot be an empty object.');
+});
+
+test('cannot add an action that have multiple keys', () => {
+  const stack = new cdk.Stack();
+  const topicRule = new iot.TopicRule(stack, 'MyTopicRule', {
+    sql: iot.IotSql.fromStringAsVer20151008("SELECT topic(2) as device_id, temperature FROM 'device/+/data'"),
+  });
+
+  const multipleKeysAction: iot.IAction = {
+    bind: () => ({
+      configuration: {
+        http: { url: 'http://example.com' },
+        lambda: { functionArn: 'test-functionArn' },
+      },
+    }),
+  };
+
+  expect(() => {
+    topicRule.addAction(multipleKeysAction);
+  }).toThrow(
+    'An action property cannot have multiple keys, received: http,lambda',
+  );
+});
+
 test('can import a TopicRule by ARN', () => {
   const stack = new cdk.Stack();