AWS:: Iotevents 构造库

本单元中更高层次的构件的API是实验性的并正在积极开发中. 在今后任何版本中,它们都须作非背向相容的修改或去除。 这些是 不适用 语义版本 模型和断开的更改 在发行笔记中宣布. 这意味着虽然你可能使用它们,但可能需要更新 当更新到此软件包的更新版本时,您的源代码.

AWS IOT 事件允许您监视您的设备或设备群 操作失败或改变,以及在发生此类事件时触发行动 发生.

DetectorModel

以下示例创建了 AWS IOT Events 检测器模型到您的堆栈 . 探测器模型至少需要参考一次AWS IOT Events输入. AWS IOT Eventions输入使探测器能够从IOT Core规则中获得MQTT有效载荷值.

您可以定义使用定时器或设置变量的内置动作,或者将数据发送到其他 AWS 资源. 另见 @aws-cdk/aws-iotevents-actions-alpha (英语) 用于其他行动.

import * as iotevents from '@aws-cdk/aws-iotevents-alpha';
import * as actions from '@aws-cdk/aws-iotevents-actions-alpha';
import * as lambda from 'aws-cdk-lib/aws-lambda';

declare const func: lambda.IFunction;

const input = new iotevents.Input(this, 'MyInput', {
  inputName: 'my_input', // optional
  attributeJsonPaths: ['payload.deviceId', 'payload.temperature'],
});

const warmState = new iotevents.State({
  stateName: 'warm',
  onEnter: [{
    eventName: 'test-enter-event',
    condition: iotevents.Expression.currentInput(input),
    actions: [new actions.LambdaInvokeAction(func)], // optional
  }],
  onInput: [{ // optional
    eventName: 'test-input-event',
    actions: [new actions.LambdaInvokeAction(func)],
  }],
  onExit: [{ // optional
    eventName: 'test-exit-event',
    actions: [new actions.LambdaInvokeAction(func)],
  }],
});
const coldState = new iotevents.State({
  stateName: 'cold',
});

// transit to coldState when temperature is less than 15
warmState.transitionTo(coldState, {
  eventName: 'to_coldState', // optional property, default by combining the names of the States
  when: iotevents.Expression.lt(
    iotevents.Expression.inputAttribute(input, 'payload.temperature'),
    iotevents.Expression.fromString('15'),
  ),
  executing: [new actions.LambdaInvokeAction(func)], // optional
});
// transit to warmState when temperature is greater than or equal to 15
coldState.transitionTo(warmState, {
  when: iotevents.Expression.gte(
    iotevents.Expression.inputAttribute(input, 'payload.temperature'),
    iotevents.Expression.fromString('15'),
  ),
});

new iotevents.DetectorModel(this, 'MyDetectorModel', {
  detectorModelName: 'test-detector-model', // optional
  description: 'test-detector-model-description', // optional property, default is none
  evaluationMethod: iotevents.EventEvaluation.SERIAL, // optional property, default is iotevents.EventEvaluation.BATCH
  detectorKey: 'payload.deviceId', // optional property, default is none and single detector instance will be created and all inputs will be routed to it
  initialState: warmState,
});

为了允许在输入中输入信息, 您可以使用 grantWrite() 方法 :

import * as iam from 'aws-cdk-lib/aws-iam';
import * as iotevents from '@aws-cdk/aws-iotevents-alpha';

declare const grantable: iam.IGrantable;
const input = iotevents.Input.fromInputName(this, 'MyInput', 'my_input');

input.grantWrite(grantable);