fix: #118 CloudFormation YAML support

.github/workflows/common-test.yml

@@ -77,6 +77,11 @@ jobs:
         run: npx vitest --retry 1 test/cdk-basic.test.ts
       - name: Test - observability mode
         run: OBSERVABLE_MODE=true npx vitest --retry 1 test/cdk-basic.test.ts
+      - name: Deploy YAML version
+        run: npm run deploy-yaml
+        working-directory: test/cdk-basic
+      - name: Test YAML
+        run: npx vitest --retry 1 test/cdk-basic.test.ts
 
   test-cdk-esm:
     runs-on: ubuntu-latest

src/cloudFormation.ts

@@ -6,6 +6,7 @@ import {
 import { AwsCredentials } from './awsCredentials.js';
 import { AwsConfiguration } from './types/awsConfiguration.js';
 import { Logger } from './logger.js';
+import * as yaml from 'yaml';
 
 let cloudFormationClient: CloudFormationClient;
 
@@ -30,7 +31,17 @@ async function getCloudFormationStackTemplate(
       throw new Error(`No template found for stack ${stackName}`);
     }
 
-    const cfTemplate = JSON.parse(response.TemplateBody);
+    let cfTemplate: any;
+    try {
+      cfTemplate = JSON.parse(response.TemplateBody);
+    } catch (parseError: any) {
+      if (parseError.message.includes('is not valid JSON')) {
+        // If the template is not JSON, try parsing it as YAML
+        cfTemplate = yaml.parse(response.TemplateBody);
+      } else {
+        throw parseError;
+      }
+    }
     return cfTemplate;
   } catch (error: any) {
     if (error.name === 'ValidationError') {

test/cdk-basic/deploy-yaml.sh

@@ -0,0 +1,15 @@
+# This script is used to deploy the CDK stack using a YAML template.
+npx cdk synth -c environment=test CdkbasicStack > CdkbasicStack.yaml
+# Add a dummy resource to the template to force a change in the stack
+awk '
+  /^Resources:/ && !injected {
+    print
+    print "  DummyForceResource:"
+    print "    Type: AWS::CloudFormation::WaitConditionHandle"
+    print "    Properties: {}"
+    injected=1
+    next
+  }
+  { print }
+' CdkbasicStack.yaml > template.patched.yaml && mv template.patched.yaml CdkbasicStack.yaml
+aws cloudformation deploy --template-file CdkbasicStack.yaml --stack-name test-lld-cdk-basic --capabilities CAPABILITY_NAMED_IAM

test/cdk-basic/package.json

@@ -7,6 +7,7 @@
   "scripts": {
     "deploy": "cdk deploy --all -c environment=test --require-approval never --outputs-file cdk-outputs.json",
     "build": "cdk synth -c environment=test",
+    "deploy-yaml": "bash deploy-yaml.sh",
     "destroy": "cdk destroy --all -c environment=test --force"
   },
   "devDependencies": {