Configuring Firehose AWS Integration in API Gateway

Applicable when

• API Gateway is used to receive events and put them into Firehose
• No complex request pre-processing required

Non-applicable when

• The request should be handler by lambda before inserting into Firehose

Implementation

The code below will show how to add API Gateway AWS integration to avoid using lambdas and directly insert data into Firehose

    this.restAPI
      .getResource('event', {   // Create resource to receive events
        defaultCorsPreflightOptions: {
          allowMethods: ['POST'],
          allowOrigins: Cors.ALL_ORIGINS,
          allowHeaders: [...Cors.DEFAULT_HEADERS, 'Api-Key'],   // Setup CORS and headers
        },
      })
      .addMethod('POST', new Integration({
        type: IntegrationType.AWS,  // Add AWS Integration
        uri: `arn:aws:apigateway:${this.region}:firehose:action/PutRecord`,
        integrationHttpMethod: 'POST',
        options: {
          credentialsRole: new Role(this, withEnv('event-role'), { // Create role to put events
            roleName: withEnv('event-role'),
            assumedBy: new ServicePrincipal('apigateway.amazonaws.com'),
            inlinePolicies: {
              allowFirehosePutRecord: PolicyDocument.fromJson({
                Version: '2012-10-17',
                Statement: [
                  {
                    Effect: 'Allow',
                    Action: ['firehose:PutRecord'],
                    Resource: '*',
                  },
                ],
              }),
            },
          }),
          requestTemplates: { // Template mapping - transform our ApiGateway request into proper format for Firehose
            'application/json': `
#set( $key = $input.params().header['Api-Key'] )
#set( $keyname = "apiKey" )
#set( $body = $input.body )
#set( $bodyobj = $util.parseJson($body) )
#set( $event = $bodyobj.event )
#set( $eventname = "event" )
#set( $userid = $bodyobj.userId )
#set( $useridname = "userid" )
#set( $productid = $bodyobj.productId )
#set( $productidname = "productid" )
#set( $price = $bodyobj.price )
#set( $pricename = "price" )
#set( $currency = $bodyobj.currency )
#set( $currencyname = "currency" )
#set( $quote = '"' )
#set( $b64 = $util.base64Encode("{$quote$keyname$quote:$quote$key$quote,$quote$eventname$quote:$quote$event$quote,$quote$useridname$quote:$quote$userid$quote,$quote$productidname$quote: $quote$productid$quote,$quote$pricename$quote: $quote$price$quote,$quote$currencyname$quote:$quote$currency$quote}") )
{
    "DeliveryStreamName": "<delivery-stream-name>",
    "Record": { "Data": "$b64" }
}
  `,
          },
          requestParameters: {
            'integration.request.header.Content-Type': "'application/x-amz-json-1.1'",
          },
          integrationResponses: [
            {
              statusCode: '200',
              responseTemplates: {
                'application/json': '{"status": "OK"}',
              },
            },
          ],
        },
      }), {
        methodResponses: [{ statusCode: '200' }],
        requestModels: {
          'application/json': ..., // Optional JSONSchema input event model
        },
        requestValidator: ..., // Optional request validator
      });