Merge pull request #448 from zirkelc/inputTransformer

Input transformer for CloudWatch / EventBridge events

Author: horike37

README.md

@@ -1001,7 +1001,7 @@ stepFunctions:
         ...
 ```
 
-#### Specify Input or Inputpath
+#### Specify Input or Inputpath or InputTransformer
 
 You can specify input values ​​to the Lambda function.
 
@@ -1034,6 +1034,19 @@ stepFunctions:
                 state:
                   - pending
             inputPath: '$.stageVariables'
+        - cloudwatchEvent:
+            event:
+              source:
+                - "aws.ec2"
+              detail-type:
+                - "EC2 Instance State-change Notification"
+              detail:
+                state:
+                  - pending
+            inputTransformer:
+              inputPathsMap:
+                stage: '$.stageVariables'
+              inputTemplate: '{ "stage": <stage> }'
       definition:
         ...
 ```

lib/deploy/events/cloudWatchEvent/compileCloudWatchEventEvents.js

@@ -23,6 +23,9 @@ module.exports = {
             let Name;
             let EventBusName;
             let IamRole;
+            let InputTransformer;
+            let InputPathsMap;
+            let InputTemplate;
             let DeadLetterConfig;
 
             if (typeof eventRule === 'object') {
@@ -42,15 +45,18 @@ module.exports = {
               }
               Input = eventRule.input;
               InputPath = eventRule.inputPath;
+              InputTransformer = eventRule.inputTransformer;
+              InputPathsMap = InputTransformer && eventRule.inputTransformer.inputPathsMap;
+              InputTemplate = InputTransformer && eventRule.inputTransformer.inputTemplate;
               Description = eventRule.description;
               Name = eventRule.name;
               EventBusName = JSON.stringify(eventRule.eventBusName);
               IamRole = eventRule.iamRole;
               DeadLetterConfig = JSON.stringify(eventRule.deadLetterConfig);
 
-              if (Input && InputPath) {
+              if ([Input, InputPath, InputTransformer].filter(Boolean).length > 1) {
                 const errorMessage = [
-                  'You can\'t set both input & inputPath properties at the',
+                  'You can\'t set input, inputPath and inputTransformer properties at the',
                   'same time for cloudwatch events.',
                   'Please check the AWS docs for more info',
                 ].join('');
@@ -64,6 +70,16 @@ module.exports = {
                 // escape quotes to favor JSON.parse
                 Input = Input.replace(/\"/g, '\\"'); // eslint-disable-line
               }
+
+              // no need to escape quotes in inputPathsMap
+              // because we add it as an object to the template
+              if (InputPathsMap && typeof InputPathsMap === 'object') {
+                InputPathsMap = JSON.stringify(InputPathsMap);
+              }
+              if (InputTemplate && typeof InputTemplate === 'string') {
+                // escape quotes to favor JSON.parse
+                InputTemplate = InputTemplate.replace(/\"/g, '\\"'); // eslint-disable-line
+              }
             } else {
               const errorMessage = [
                 `CloudWatch event of stateMachine "${stateMachineName}" is not an object`,
@@ -94,6 +110,10 @@ module.exports = {
                   "Targets": [{
                     ${Input ? `"Input": "${Input.replace(/\\n|\\r/g, '')}",` : ''}
                     ${InputPath ? `"InputPath": "${InputPath.replace(/\r?\n/g, '')}",` : ''}
+                    ${InputTransformer ? `"InputTransformer": {
+                      "InputPathsMap": ${InputPathsMap},
+                      "InputTemplate": "${InputTemplate}"
+                    },` : ''}
                     "Arn": { "Ref": "${stateMachineLogicalId}" },
                     "Id": "${cloudWatchId}",
                     ${DeadLetterConfig ? `"DeadLetterConfig":{ "Arn" : ${DeadLetterConfig} },` : ''}

lib/deploy/events/cloudWatchEvent/compileCloudWatchEventEvents.test.js

@@ -419,7 +419,43 @@ describe('awsCompileCloudWatchEventEvents', () => {
         .Properties.Targets[0].Input).to.equal('{"key":"value"}');
     });
 
-    itParam('should throw an error when both Input and InputPath are set', ['cloudwatchEvent', 'eventBridge'], (source) => {
+    itParam('should respect inputTransformer variable', ['cloudwatchEvent', 'eventBridge'], (source) => {
+      serverlessStepFunctions.serverless.service.stepFunctions = {
+        stateMachines: {
+          first: {
+            events: [
+              {
+                [source]: {
+                  event: {
+                    source: ['aws.ec2'],
+                    'detail-type': ['EC2 Instance State-change Notification'],
+                    detail: { state: ['pending'] },
+                  },
+                  enabled: false,
+                  inputTransformer: {
+                    inputPathsMap: {
+                      stage: '$.stageVariables',
+                    },
+                    inputTemplate: '{ "stage": <stage> }',
+                  },
+                },
+              },
+            ],
+          },
+        },
+      };
+
+      serverlessStepFunctions.compileCloudWatchEventEvents();
+
+      expect(serverlessStepFunctions.serverless.service
+        .provider.compiledCloudFormationTemplate.Resources.FirstEventsRuleCloudWatchEvent1
+        .Properties.Targets[0].InputTransformer.InputPathsMap).to.have.property('stage', '$.stageVariables');
+      expect(serverlessStepFunctions.serverless.service
+        .provider.compiledCloudFormationTemplate.Resources.FirstEventsRuleCloudWatchEvent1
+        .Properties.Targets[0].InputTransformer.InputTemplate).to.equal('{ "stage": <stage> }');
+    });
+
+    itParam('should throw an error when Input and InputPath and InputTransformer are set', ['cloudwatchEvent', 'eventBridge'], (source) => {
       serverlessStepFunctions.serverless.service.stepFunctions = {
         stateMachines: {
           first: {
@@ -436,6 +472,12 @@ describe('awsCompileCloudWatchEventEvents', () => {
                     key: 'value',
                   },
                   inputPath: '$.stageVariables',
+                  inputTransformer: {
+                    inputPathsMap: {
+                      stage: '$.stageVariables',
+                    },
+                    inputTemplate: '{ "stage": <stage> }',
+                  },
                 },
               },
             ],