feat: add VPC Lattice support (#696)

* First draft

* Add logging

* Logic analog to ALB

* Logs

* Fix for method

* Remove log

* Test event body without Buffer

* Keep using the Buffer

* Adapt headers logic

* Header adaptions in response

* Send response headers as array

* feat: unit tests and fixes

* feat: update README

* feat: handle v1 event

* feat: fix

* feat: update docs

* feat: remove query from path

* feat: fix test

* feat: fix test

* feat: another try

* feat: test

* feat: cleanup

---------

Co-authored-by: Christoph Windpassinger <extern.christoph.windpassinger@vwfs.io>

Author: ChristophWindpassinger

README.md

@@ -144,7 +144,7 @@ The _out-binding_ parameter `"name": "$return"` is important for Serverless Expr
 
 1. Improved API - Simpler for end-user to use and configure.
 1. Promise resolution mode by default. Can specify `resolutionMode` to use `"CONTEXT"` or `"CALLBACK"`
-1. Additional event sources - API Gateway V1 (REST API), API Gateway V2 (HTTP API), ALB, Lambda@Edge
+1. Additional event sources - API Gateway V1 (REST API), API Gateway V2 (HTTP API), ALB, Lambda@Edge, VPC Lattice
 1. Custom event source - If you have another event source you'd like to use that we don't natively support, check out the [DynamoDB Example](examples/custom-mapper-dynamodb)
 1. Implementation uses mock Request/Response objects instead of running a server listening on a local socket. Thanks to @dougmoscrop from https://github.com/dougmoscrop/serverless-http
 1. Automatic `isBase64Encoded` without specifying `binaryMimeTypes`. Use `binarySettings` to customize. Thanks to @dougmoscrop from https://github.com/dougmoscrop/serverless-http
@@ -201,7 +201,7 @@ Set this to true to have serverless-express include the error stack trace in the
 
 ### eventSource
 
-serverless-express natively supports API Gateway, ALB, and Lambda@Edge. If you want to use Express with other AWS Services integrated with Lambda you can provide your own custom request/response mappings via `eventSource`. See the [custom-mapper-dynamodb example](examples/custom-mapper-dynamodb).
+serverless-express natively supports API Gateway, ALB, Lambda@Edge and VPC Lattice (only V2 events - event source `AWS_VPC_LATTICE_V2`). If you want to use Express with other AWS Services integrated with Lambda you can provide your own custom request/response mappings via `eventSource`. See the [custom-mapper-dynamodb example](examples/custom-mapper-dynamodb).
 
 ```js
 function requestMapper ({ event }) {

__tests__/unit.lattice.js

@@ -0,0 +1,45 @@
+const eventSources = require('../src/event-sources')
+const testUtils = require('./utils')
+
+const latticeEventSource = eventSources.getEventSource({
+  eventSourceName: 'AWS_VPC_LATTICE_V2'
+})
+
+test('request is correct', () => {
+  const req = getReq()
+  expect(typeof req).toEqual('object')
+  expect(req.method).toEqual('GET')
+  expect(req.path).toEqual('/test-path?key=value')
+  expect(req.headers).toEqual({
+    'x-custom-header': 'test-header',
+    'content-length': 15
+  })
+  expect(Buffer.isBuffer(req.body)).toEqual(true)
+})
+
+test('response is correct', () => {
+  const res = getRes()
+  expect(typeof res).toEqual('object')
+  expect(res.statusCode).toEqual(200)
+  expect(res.body).toEqual('{"message":"Hello, world!"}')
+  expect(res.headers).toEqual({ 'Content-Type': 'application/json' })
+  expect(res.isBase64Encoded).toEqual(false)
+})
+
+function getReq () {
+  const event = testUtils.latticeEvent
+  const request = latticeEventSource.getRequest({ event })
+  return request
+}
+
+function getRes () {
+  const event = testUtils.latticeEvent
+  const response = latticeEventSource.getResponse({
+    event,
+    statusCode: 200,
+    body: '{"message":"Hello, world!"}',
+    headers: { 'Content-Type': 'application/json' },
+    isBase64Encoded: false
+  })
+  return response
+}

__tests__/utils.js

@@ -267,6 +267,23 @@ const selfManagedKafkaEvent = {
   }
 }
 
+const latticeEvent = {
+  version: '2.0',
+  method: 'GET',
+  path: '/test-path?key=value',
+  queryStringParameters: { key: ['value'] },
+  headers: { 'x-custom-header': ['test-header'] },
+  body: JSON.stringify({ key: 'value' }),
+  requestContext: {
+    serviceNetworkArn: 'arn:aws:vpc-lattice:eu-central-1:123456789:servicenetwork/sn-123',
+    serviceArn: 'arn:aws:vpc-lattice:eu-central-1:014538609594:service/svc-123',
+    targetGroupArn: 'arn:aws:vpc-lattice:eu-central-1:014538609594:targetgroup/tg-123',
+    identity: {
+      sourceVpcArn: 'arn:aws:ec2:eu-central-1:123456789:vpc/vpc-123'
+    }
+  }
+}
+
 describe('getEventSourceNameBasedOnEvent', () => {
   test('throws error on empty event', () => {
     expect(() => getEventSourceNameBasedOnEvent({ event: {} })).toThrow(
@@ -318,6 +335,11 @@ describe('getEventSourceNameBasedOnEvent', () => {
     const result = getEventSourceNameBasedOnEvent({ event: eventbridgeCustomerEvent })
     expect(result).toEqual('AWS_EVENTBRIDGE')
   })
+
+  test('recognizes lattice event', () => {
+    const result = getEventSourceNameBasedOnEvent({ event: latticeEvent })
+    expect(result).toEqual('AWS_VPC_LATTICE_V2')
+  })
 })
 
 module.exports = {
@@ -329,5 +351,6 @@ module.exports = {
   eventbridgeScheduledEvent,
   eventbridgeCustomerEvent,
   kinesisDataStreamEvent,
-  selfManagedKafkaEvent
+  selfManagedKafkaEvent,
+  latticeEvent
 }

src/event-sources/aws/lattice.js

@@ -0,0 +1,35 @@
+const { getRequestValuesFromEvent, getCommaDelimitedHeaders } = require('../utils')
+
+const getRequestValuesFromLatticeEvent = ({ event }) => {
+  const values = getRequestValuesFromEvent({
+    event,
+    method: event.method,
+    path: event.path // query parameters are already included in the path
+  })
+
+  // Lattice always sends the headers as array that needs to be converted to a comma delimited string
+  values.headers = getCommaDelimitedHeaders({ headersMap: event.headers, lowerCaseKey: true })
+
+  return values
+}
+
+const getResponseToLattice = ({
+  statusCode,
+  body,
+  headers: responseHeaders,
+  isBase64Encoded
+}) => {
+  const headers = getCommaDelimitedHeaders({ headersMap: responseHeaders })
+
+  return {
+    statusCode,
+    body,
+    headers,
+    isBase64Encoded
+  }
+}
+
+module.exports = {
+  getRequest: getRequestValuesFromLatticeEvent,
+  getResponse: getResponseToLattice
+}

src/event-sources/index.js

@@ -12,6 +12,7 @@ const awsKinesisEventSource = require('./aws/kinesis')
 const awsS3 = require('./aws/s3')
 const awsStepFunctionsEventSource = require('./aws/step-functions')
 const awsSelfManagedKafkaEventSource = require('./aws/self-managed-kafka')
+const awsLatticeEventSource = require('./aws/lattice')
 
 function getEventSource ({ eventSourceName }) {
   switch (eventSourceName) {
@@ -43,6 +44,8 @@ function getEventSource ({ eventSourceName }) {
       return awsStepFunctionsEventSource
     case 'AWS_SELF_MANAGED_KAFKA':
       return awsSelfManagedKafkaEventSource
+    case 'AWS_VPC_LATTICE_V2':
+      return awsLatticeEventSource
     default:
       throw new Error('Couldn\'t detect valid event source.')
   }

src/event-sources/utils.js

@@ -71,6 +71,10 @@ function getEventSourceNameBasedOnEvent ({
   event
 }) {
   if (event.requestContext && event.requestContext.elb) return 'AWS_ALB'
+  if (event.headers?.['x-amzn-lattice-network']) {
+    console.warn('Lattice event v1 is not supported. Please use Lattice event v2.')
+  }
+  if (event.requestContext && event.requestContext.serviceNetworkArn && event.requestContext.serviceArn) return 'AWS_VPC_LATTICE_V2'
   if (event.eventSource === 'SelfManagedKafka') return 'AWS_SELF_MANAGED_KAFKA'
   if (event.Records) {
     const eventSource = event.Records[0] ? event.Records[0].EventSource || event.Records[0].eventSource : undefined