Direct integration between Amazon API Gateway and Amazon EventBridge

shared-resources-stack.ts

// .. creation of the eventbus above

const sharedEdaApi: apigw.RestApi = new apigw.RestApi(
  this,
  'SharedEdaApi',
  {
    description: 'shared eda api',
    restApiName: 'shared-eda-api',
    deploy: true,
    deployOptions: {
      stageName: 'prod',
      dataTraceEnabled: true,
      loggingLevel: apigw.MethodLoggingLevel.INFO,
      tracingEnabled: true,
      metricsEnabled: true,
    },
  }
);

const externalDomainEvents: apigw.Resource =
  sharedEdaApi.root.addResource('events');

const apigwRole: iam.Role = new iam.Role(this, 'ApigwSharedEventBusRole', {
  assumedBy: new iam.ServicePrincipal('apigateway.amazonaws.com'),
  inlinePolicies: {
    putEvents: new iam.PolicyDocument({
      statements: [
        new iam.PolicyStatement({
          actions: ['events:PutEvents'],
          resources: [sharedEventBus.eventBusArn],
        }),
      ],
    }),
  },
});

const eventBridgeOptions: apigw.IntegrationOptions = {
  credentialsRole: apigwRole,
  requestParameters: {
    'integration.request.header.X-Amz-Target': "'AWSEvents.PutEvents'",
    'integration.request.header.Content-Type':
      "'application/x-amz-json-1.1'",
  },
  requestTemplates: {
    'application/json': `{"Entries": [{"Source": "$util.escapeJavaScript($input.path('$.metadata.source'))", "Detail":"$util.escapeJavaScript($input.json('$'))", "DetailType": "$util.escapeJavaScript($input.path('$.metadata.eventName'))", "EventBusName": "${sharedEventBus.eventBusName}"}]}`,
  },
  integrationResponses: [
    {
      statusCode: '200',
      responseTemplates: {
        'application/json': 'Created',
      },
    },
  ],
};

externalDomainEvents.addMethod(
  'POST',
  new apigw.Integration({
    type: apigw.IntegrationType.AWS,
    uri: `arn:aws:apigateway:${cdk.Aws.REGION}:events:path//`,
    integrationHttpMethod: 'POST',
    options: eventBridgeOptions,
  }),
  { methodResponses: [{ statusCode: '200' }] }
);