order-stack.ts

import { Construct } from 'constructs';
import * as events from 'aws-cdk-lib/aws-events'
import { LambdaFunction as LambdaFunctionTarget } from 'aws-cdk-lib/aws-events-targets'
import * as nodeLambda from 'aws-cdk-lib/aws-lambda-nodejs'
import * as lambda from 'aws-cdk-lib/aws-lambda'
import * as apigw from 'aws-cdk-lib/aws-apigateway'
import { BaseStack, BaseStackProps } from './base-stack';
import { RetentionDays } from 'aws-cdk-lib/aws-logs';
import { CfnOutput } from 'aws-cdk-lib';
import { POWERTOOLS_METRICS_NAMESPACE } from '../src/lambda-common';

/**
 * Application to manage customer order
 * 
 * An HTTP endpoint is created to receive orders from customers.
 * When an order is created, an Order.Created event is sent.
 * When a delivery update is received, the order is updated and an Order.Updated event is sent.
 */
export class OrderServiceStack extends BaseStack {
  localBus: events.EventBus
  identifier: string

  constructor(scope: Construct, id: string, props: BaseStackProps) {
    super(scope, id, props);
    this.identifier = props.identifier
    this.createOrderCreateFunction()
    this.createDeliveryUpdateFunction()
  }

  createOrderCreateFunction() {
    const createOrderFunction = new nodeLambda.NodejsFunction(this, 'CreateOrderFunction', {
      entry: './src/order-handler.ts',
      runtime: lambda.Runtime.NODEJS_18_X,
      handler: 'handleOrderCreate',
      environment: {
        BUS_ARN: this.globalBus.eventBusArn,
        SERVICE_IDENTIFIER: this.identifier,
        POWERTOOLS_SERVICE_NAME: 'OrderCreate',
        POWERTOOLS_METRICS_NAMESPACE
      },
      logRetention: RetentionDays.ONE_WEEK,
      tracing: lambda.Tracing.ACTIVE,
    })
    createOrderFunction.addToRolePolicy(this.globalBusPutEventsStatement)
    const api = new apigw.RestApi(this, 'OrderApi', { restApiName: 'order' })
    api.root.addMethod('POST', new apigw.LambdaIntegration(createOrderFunction))

    new CfnOutput(this, 'apiEndpoint', {
      value: `https://${api.restApiId}.execute-api.${this.region}.${this.urlSuffix}/${api.deploymentStage.stageName}`
    })
  }

  createDeliveryUpdateFunction() {
    const deliveryUpdateFunction = new nodeLambda.NodejsFunction(this, 'DeliveryUpdateFunction', {
      entry: './src/order-handler.ts',
      runtime: lambda.Runtime.NODEJS_18_X,
      handler: 'handleDeliveryUpdate',
      environment: {
        BUS_ARN: this.globalBus.eventBusArn,
        SERVICE_IDENTIFIER: this.identifier,
        POWERTOOLS_SERVICE_NAME: 'DeliveryUpdate',
        POWERTOOLS_METRICS_NAMESPACE
      },
      logRetention: RetentionDays.ONE_WEEK,
      tracing: lambda.Tracing.ACTIVE,
    })
    deliveryUpdateFunction.addToRolePolicy(this.globalBusPutEventsStatement)

    // React to delivery events
    const deliveryEventsRule = new events.Rule(this, 'DeliveryHandlingRule', {
      eventBus: this.localBus,
      ruleName: 'order-service-rule',
      eventPattern: {
        detailType: ['Delivery.Updated'],
      }
    })
    deliveryEventsRule.addTarget(new LambdaFunctionTarget(deliveryUpdateFunction))

    new CfnOutput(this, 'deliveryEventsRule', {
      value: deliveryEventsRule.ruleName
    })

    new CfnOutput(this, 'deliveryEventsRuleTarget', {
      value: 'Target0'
    })
  }
}