Bypass lambda execution when exepection warmer event

Author: SkippyZA

src/utils/run-handler-with-middleware.js

@@ -1,4 +1,5 @@
 import composeMiddleware from './compose-middleware'
+import isCloudwatchTrigger from './is-cloudwatch-trigger'
 import PluginHook from '../enums/hooks'
 
 export default function runHandlerWithMiddleware (fn, cb, responseObject, registeredPlugins = [], options = {}) {
@@ -48,6 +49,12 @@ export default function runHandlerWithMiddleware (fn, cb, responseObject, regist
         })
     }
 
+    // Skip the invocation if we expecting the event to be a cloudwatch trigger used for
+    // warming the lambda
+    if ((options.allowWarming || false) && isCloudwatchTrigger(event)) {
+      return Promise.resolve(cb(null, null, callback))
+    }
+
     // Execute the middleware stack using the above request and response
     return Promise.resolve()
       .then(() => runInit())

test/support/sample-cloudwatch-event.json

@@ -0,0 +1,10 @@
+{
+  "id": "53dc4d37-cffa-4f76-80c9-8b7d4a4d2eaa",
+  "detail-type": "Scheduled Event",
+  "source": "aws.events",
+  "account": "123456789012",
+  "time": "2015-10-08T16:53:06Z",
+  "region": "us-east-1",
+  "resources": [ "arn:aws:events:us-east-1:123456789012:rule/MyScheduledRule" ],
+  "detail": {}
+}

test/unit/handlers/api-gateway.spec.js

@@ -1,6 +1,7 @@
 /* eslint-disable no-unused-expressions */
 import { should, expect } from 'chai'
-import { ApiGateway, AbstractLambdaPlugin, Enums } from '../../../src/index.js'
+import { ApiGateway, AbstractLambdaPlugin, Enums } from '../../../src'
+import SampleCloudwatchEvent from '../../support/sample-cloudwatch-event'
 
 describe('api-gateway decorator', () => {
   before(() => {
@@ -86,5 +87,23 @@ describe('api-gateway decorator', () => {
         done()
       })
     })
+
+    it('should not execute anything if the lambda allows to be warmed and a cloudwatch schedule event invokes it', (done) => {
+      class Test {
+        @ApiGateway({ allowWarming: true })
+        testMethod (event) {
+          return Promise.resolve(event.test)
+        }
+      }
+
+      const test = new Test()
+
+      test.testMethod(SampleCloudwatchEvent, null, (err, res) => {
+        expect(err).to.be.null()
+        expect(res).to.be.null()
+
+        done()
+      })
+    })
   })
 })

test/unit/utils/is-cloudwatch-trigger.spec.js

@@ -1,15 +1,5 @@
-import isCloudwatchTrigger from '../../../src/utils/is-cloudwatch-trigger.js'
-
-const sampleCloudwatchEvent = {
-  id: '53dc4d37-cffa-4f76-80c9-8b7d4a4d2eaa',
-  'detail-type': 'Scheduled Event',
-  source: 'aws.events',
-  account: '123456789012',
-  time: '2015-10-08T16:53:06Z',
-  region: 'us-east-1',
-  resources: [ 'arn:aws:events:us-east-1:123456789012:rule/MyScheduledRule' ],
-  detail: {}
-}
+import isCloudwatchTrigger from '../../../src/utils/is-cloudwatch-trigger'
+import sampleCloudwatchEvent from '../../support/sample-cloudwatch-event'
 
 describe('isCloudwatchTrigger', () => {
   it('should return true for a cloudwatch event', () => {