fix: fixing issue with async error handling within the SERVERLESS_EXPRESS:PROXY

This change handles non-async and async errors thrown within `forwardRequestToNodeServer` and adds an integration test (this was previously skipped).

Author: Jack-Overflow

__tests__/integration-alb.js

@@ -6,7 +6,7 @@ const {
 } = require('../jest-helpers')
 
 describe('alb:express integration tests', () => {
-  test('reasponse headers are of type string', async () => {
+  test('response headers are of type string', async () => {
     const app = express()
     const router = express.Router()
     app.use('/', router)
@@ -15,14 +15,14 @@ describe('alb:express integration tests', () => {
       res.send('123')
     })
     const event = makeEvent({
-      eventSourceName: 'alb',
+      eventSourceName: 'AWS_ALB',
       path: '/foo',
       httpMethod: 'GET',
       headers: {}
     })
     const response = await serverlessExpressInstance(event)
     const expectedResponse = makeResponse({
-      eventSourceName: 'alb',
+      eventSourceName: 'AWS_ALB',
       body: '123',
       headers: {
         'content-length': '3',

__tests__/integration.js

@@ -10,6 +10,7 @@ const {
   makeResponse,
   EACH_MATRIX
 } = require('../jest-helpers')
+const { getEventSource } = require('../src/event-sources')
 const jestHelpersPath = path.join(__dirname, '..', 'jest-helpers')
 
 let app, router, serverlessExpressInstance
@@ -115,7 +116,7 @@ describe.each(EACH_MATRIX)('%s:%s: integration tests', (eventSourceName, framewo
       res.json({ xHeaders })
     })
     const event = makeEvent({
-      eventSourceName: 'apiGatewayV1',
+      eventSourceName: 'AWS_API_GATEWAY_V1',
       path: '/foo',
       httpMethod: 'GET',
       multiValueHeaders: undefined,
@@ -126,7 +127,7 @@ describe.each(EACH_MATRIX)('%s:%s: integration tests', (eventSourceName, framewo
     })
     const response = await serverlessExpressInstance(event)
     const expectedResponse = makeResponse({
-      eventSourceName: 'apiGatewayV1',
+      eventSourceName: 'AWS_API_GATEWAY_V1',
       body: JSON.stringify({
         xHeaders: {
           'x-header-one': 'Value1',
@@ -265,31 +266,31 @@ describe.each(EACH_MATRIX)('%s:%s: integration tests', (eventSourceName, framewo
     const etagRegex = /^W\/.*$/
     const lastModifiedRegex = /^.* GMT$/
     switch (eventSourceName) {
-      case 'alb':
-      case 'apiGatewayV1':
+      case 'AWS_ALB':
+      case 'AWS_API_GATEWAY_V1':
         expect(response.multiValueHeaders.etag.length).toEqual(1)
         expect(response.multiValueHeaders.etag[0]).toMatch(etagRegex)
         expect(response.multiValueHeaders['last-modified'].length).toEqual(1)
         expect(response.multiValueHeaders['last-modified'][0]).toMatch(lastModifiedRegex)
         delete response.multiValueHeaders.etag
         delete response.multiValueHeaders['last-modified']
         break
-      case 'azureHttpFunctionV4':
-      case 'azureHttpFunctionV3':
+      case 'AZURE_HTTP_FUNCTION_V4':
+      case 'AZURE_HTTP_FUNCTION_V3':
         expectedResponse.body = Buffer.from(samLogoBase64, 'base64')
         expectedResponse.isBase64Encoded = false
         expect(response.headers.etag).toMatch(etagRegex)
         expect(response.headers['last-modified']).toMatch(lastModifiedRegex)
         delete response.headers.etag
         delete response.headers['last-modified']
         break
-      case 'apiGatewayV2':
+      case 'AWS_API_GATEWAY_V2':
         expect(response.headers.etag).toMatch(etagRegex)
         expect(response.headers['last-modified']).toMatch(lastModifiedRegex)
         delete response.headers.etag
         delete response.headers['last-modified']
         break
-      case 'lambdaEdge':
+      case 'AWS_LAMBDA_EDGE':
         expect(response.headers.etag.length).toEqual(1)
         expect(response.headers.etag[0].key).toMatch('etag')
         expect(response.headers.etag[0].value).toMatch(etagRegex)
@@ -420,12 +421,56 @@ describe.each(EACH_MATRIX)('%s:%s: integration tests', (eventSourceName, framewo
     expect(response).toEqual(expectedResponse)
   })
 
-  test.skip('respondToEventSourceWithError', async () => {
-    const response = await serverlessExpressInstance(null)
-    expect(response).toEqual({
-      statusCode: 500,
-      body: '',
-      multiValueHeaders: {}
+  describe('respondToEventSourceWithError', () => {
+    let event
+    let eventSource
+    let getRequestSpy
+
+    beforeEach(() => {
+      event = makeEvent({
+        eventSourceName,
+        path: '/users',
+        httpMethod: 'GET'
+      })
+      eventSource = getEventSource({ eventSourceName })
+      getRequestSpy = jest.spyOn(eventSource, 'getRequest').mockImplementation(() => {
+        throw new URIError('URI malformed')
+      })
+    })
+
+    afterEach(() => {
+      getRequestSpy.mockRestore()
+    })
+
+    test('respondWithErrors: true', async () => {
+      serverlessExpressInstance = serverlessExpress({
+        app,
+        eventSource,
+        respondWithErrors: true
+      })
+
+      const response = await serverlessExpressInstance(event)
+      const statusCode = response.statusCode || response.status
+
+      expect(statusCode).toBe(500)
+      expect(response.body).toContain('URIError')
+      expect(response.body).toContain('URI malformed')
+      expect(getRequestSpy).toHaveBeenCalledWith(expect.objectContaining({ event }))
+    })
+
+    test('respondWithErrors: false', async () => {
+      serverlessExpressInstance = serverlessExpress({
+        app,
+        eventSource,
+        respondWithErrors: false
+      })
+
+      const response = await serverlessExpressInstance(event)
+      const statusCode = response.statusCode || response.status
+
+      expect(statusCode).toBe(500)
+      expect(response.body).toEqual('')
+      expect(getRequestSpy).toHaveBeenCalledWith(expect.objectContaining({ event }))
     })
   })
 
@@ -471,8 +516,8 @@ describe.each(EACH_MATRIX)('%s:%s: integration tests', (eventSourceName, framewo
     jest.useRealTimers()
 
     switch (eventSourceName) {
-      case 'azureHttpFunctionV4':
-      case 'azureHttpFunctionV3':
+      case 'AZURE_HTTP_FUNCTION_V4':
+      case 'AZURE_HTTP_FUNCTION_V3':
         expectedResponse.cookies = [
           {
             domain: 'mafoo.com',

jest-helpers/index.js

@@ -6,12 +6,12 @@ const { makeAzureHttpFunctionV3Event, makeAzureHttpFunctionV3Response } = requir
 const { makeAzureHttpFunctionV4Event, makeAzureHttpFunctionV4Response } = require('./azure-http-function-v4-event')
 
 const EVENT_SOURCE_NAMES = [
-  'alb',
-  'apiGatewayV1',
-  'apiGatewayV2',
-  'lambdaEdge',
-  'azureHttpFunctionV3',
-  'azureHttpFunctionV4'
+  'AWS_ALB',
+  'AWS_API_GATEWAY_V1',
+  'AWS_API_GATEWAY_V2',
+  'AWS_LAMBDA_EDGE',
+  'AZURE_HTTP_FUNCTION_V3',
+  'AZURE_HTTP_FUNCTION_V4'
 ]
 
 const FRAMEWORK_NAMES = [
@@ -49,17 +49,17 @@ class MockContext {
 
 function makeEvent ({ eventSourceName, ...rest }) {
   switch (eventSourceName) {
-    case 'alb':
+    case 'AWS_ALB':
       return makeAlbEvent(rest)
-    case 'apiGatewayV1':
+    case 'AWS_API_GATEWAY_V1':
       return makeApiGatewayV1Event(rest)
-    case 'apiGatewayV2':
+    case 'AWS_API_GATEWAY_V2':
       return makeApiGatewayV2Event(rest)
-    case 'lambdaEdge':
+    case 'AWS_LAMBDA_EDGE':
       return makeLambdaEdgeEvent(rest)
-    case 'azureHttpFunctionV3':
+    case 'AZURE_HTTP_FUNCTION_V3':
       return makeAzureHttpFunctionV3Event(rest)
-    case 'azureHttpFunctionV4':
+    case 'AZURE_HTTP_FUNCTION_V4':
       return makeAzureHttpFunctionV4Event(rest)
     default:
       throw new Error(`Unknown eventSourceName ${eventSourceName}`)
@@ -68,17 +68,17 @@ function makeEvent ({ eventSourceName, ...rest }) {
 
 function makeResponse ({ eventSourceName, ...rest }, { shouldConvertContentLengthToInt = false } = {}) {
   switch (eventSourceName) {
-    case 'alb':
+    case 'AWS_ALB':
       return makeAlbResponse(rest)
-    case 'apiGatewayV1':
+    case 'AWS_API_GATEWAY_V1':
       return makeApiGatewayV1Response(rest)
-    case 'apiGatewayV2':
+    case 'AWS_API_GATEWAY_V2':
       return makeApiGatewayV2Response(rest, { shouldConvertContentLengthToInt })
-    case 'lambdaEdge':
+    case 'AWS_LAMBDA_EDGE':
       return makeLambdaEdgeResponse(rest)
-    case 'azureHttpFunctionV3':
+    case 'AZURE_HTTP_FUNCTION_V3':
       return makeAzureHttpFunctionV3Response(rest, { shouldConvertContentLengthToInt })
-    case 'azureHttpFunctionV4':
+    case 'AZURE_HTTP_FUNCTION_V4':
       return makeAzureHttpFunctionV4Response(rest, { shouldConvertContentLengthToInt })
     default:
       throw new Error(`Unknown eventSourceName ${eventSourceName}`)

package-lock.json

@@ -68,6 +68,17 @@ function configure ({
         promise,
         resolutionMode
       })
+      const handleError = (error) => {
+        respondToEventSourceWithError({
+          error,
+          resolver,
+          log,
+          respondWithErrors,
+          eventSourceName,
+          eventSource,
+          event
+        })
+      }
 
       try {
         forwardRequestToNodeServer({
@@ -81,16 +92,9 @@ function configure ({
           eventSource,
           eventSourceRoutes,
           log
-        })
+        }).catch(handleError)
       } catch (error) {
-        respondToEventSourceWithError({
-          error,
-          resolver,
-          log,
-          respondWithErrors,
-          eventSourceName,
-          eventSource
-        })
+        handleError(error)
       }
     })
   }

src/configure.js

@@ -55,7 +55,8 @@ function respondToEventSourceWithError ({
   log,
   respondWithErrors,
   eventSourceName,
-  eventSource
+  eventSource,
+  event
 }) {
   log.error('SERVERLESS_EXPRESS:RESPOND_TO_EVENT_SOURCE_WITH_ERROR', error)
 
@@ -73,6 +74,7 @@ function respondToEventSourceWithError ({
 
   const body = respondWithErrors ? error.stack : ''
   const errorResponse = eventSource.getResponse({
+    event,
     statusCode: 500,
     body,
     headers: {},