feat: retain config

README.md

@@ -11,6 +11,7 @@ This is the Serverless Framework plugin for AWS Step Functions.
      - [Adding a custom name for a state machine](#adding-a-custom-name-for-a-statemachine)
      - [Adding a custom logical id for a stateMachine](#adding-a-custom-logical-id-for-a-statemachine)
      - [Depending on another logical id](#depending-on-another-logical-id)
+     - [Adding retain property for a state machine](#adding-retain-property-for-a-statemachine)
      - [CloudWatch Alarms](#cloudwatch-alarms)
      - [CloudWatch Notifications](#cloudwatch-notifications)
      - [Blue-Green deployments](#blue-green-deployment)
@@ -219,6 +220,17 @@ stepFunctions:
         - myOtherDB
         - myStream
 ```
+### Adding retain property for a stateMachine
+There are some practical cases when you would like to prevent state machine from deletion on stack delete or update. This can be achieved by adding `retain` property to the state machine section.
+
+```yaml
+stepFunctions:
+  stateMachines:
+    myStateMachine:
+      retain: true
+```
+
+Configuring in such way adds `"DeletionPolicy" : "Retain"` to the state machine within CloudFormation template.
 
 ### CloudWatch Alarms
 

lib/deploy/stepFunctions/compileStateMachines.js

@@ -224,6 +224,10 @@ module.exports = {
           [stateMachineLogicalId]: stateMachineTemplate,
         };
 
+        if (stateMachineObj.retain) {
+          newStateMachineObject[stateMachineLogicalId].DeletionPolicy = 'Retain';
+        }
+
         if (stateMachineObj.name) {
           newStateMachineObject[
             stateMachineLogicalId].Properties.StateMachineName = stateMachineObj.name;

lib/deploy/stepFunctions/compileStateMachines.schema.js

@@ -42,6 +42,7 @@ const alarms = Joi.object();
 const notifications = Joi.object();
 const useExactVersion = Joi.boolean().default(false);
 const type = Joi.string().valid('STANDARD', 'EXPRESS').default('STANDARD');
+const retain = Joi.boolean().default(false);
 
 const schema = Joi.object().keys({
   id,
@@ -55,6 +56,7 @@ const schema = Joi.object().keys({
   alarms,
   notifications,
   type,
+  retain,
   loggingConfig,
   inheritGlobalTags,
 });

lib/deploy/stepFunctions/compileStateMachines.test.js

@@ -1430,4 +1430,22 @@ describe('#compileStateMachines', () => {
     expect(Object.keys(serverlessStepFunctions.serverless.service.provider
       .compiledCloudFormationTemplate.Outputs).length).to.equal(0);
   });
+
+  it('should add DeletionPolicy when retain is true', () => {
+    serverless.service.stepFunctions = {
+      stateMachines: {
+        myStateMachine1: {
+          definition: 'definition1',
+          name: 'stateMachineBeta1',
+          retain: true,
+        },
+      },
+    };
+
+    serverlessStepFunctions.compileStateMachines();
+
+    expect(serverlessStepFunctions.serverless.service
+      .provider.compiledCloudFormationTemplate.Resources
+      .StateMachineBeta1.DeletionPolicy).to.equal('Retain');
+  });
 });