feat(cfn-include): handle resources not in the CloudFormation schema (#…

…9199)

Closes  #9197

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/cloudformation-include/README.md

@@ -106,6 +106,10 @@ const bucket = s3.Bucket.fromBucketName(this, 'L2Bucket', cfnBucket.ref);
 // bucket is of type s3.IBucket
 ```
 
+Note that [Custom Resources](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-cfn-customresource.html)
+will be of type CfnResource, and hence won't need to be casted.
+This holds for any resource that isn't in the CloudFormation schema.
+
 ## Conditions
 
 If your template uses [CloudFormation Conditions](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/conditions-section-structure.html),

packages/@aws-cdk/cloudformation-include/lib/cfn-include.ts

@@ -311,12 +311,7 @@ export class CfnInclude extends core.CfnElement {
     }
 
     const resourceAttributes: any = this.template.Resources[logicalId];
-    const l1ClassFqn = cfn_type_to_l1_mapping.lookup(resourceAttributes.Type);
-    if (!l1ClassFqn) {
-      // currently, we only handle types we know the L1 for -
-      // in the future, we might construct an instance of CfnResource instead
-      throw new Error(`Unrecognized CloudFormation resource type: '${resourceAttributes.Type}'`);
-    }
+
     // fail early for resource attributes we don't support yet
     const knownAttributes = [
       'Type', 'Properties', 'Condition', 'DependsOn', 'Metadata',
@@ -329,9 +324,6 @@ export class CfnInclude extends core.CfnElement {
       }
     }
 
-    const [moduleName, ...className] = l1ClassFqn.split('.');
-    const module = require(moduleName);  // eslint-disable-line @typescript-eslint/no-require-imports
-    const jsClassFromModule = module[className.join('.')];
     const self = this;
     const finder: core.ICfnFinder = {
       findCondition(conditionName: string): core.CfnCondition | undefined {
@@ -353,13 +345,31 @@ export class CfnInclude extends core.CfnElement {
         return this.findResource(elementName);
       },
     };
-    const options: core.FromCloudFormationOptions = {
+    const cfnParser = new cfn_parse.CfnParser({
       finder,
-    };
+    });
 
-    const l1Instance = this.nestedStacksToInclude[logicalId]
-      ? this.createNestedStack(logicalId, finder)
-      : jsClassFromModule.fromCloudFormation(this, logicalId, resourceAttributes, options);
+    let l1Instance: core.CfnResource;
+    if (this.nestedStacksToInclude[logicalId]) {
+      l1Instance = this.createNestedStack(logicalId, cfnParser);
+    } else {
+      const l1ClassFqn = cfn_type_to_l1_mapping.lookup(resourceAttributes.Type);
+      if (l1ClassFqn) {
+        const options: core.FromCloudFormationOptions = {
+          finder,
+        };
+        const [moduleName, ...className] = l1ClassFqn.split('.');
+        const module = require(moduleName);  // eslint-disable-line @typescript-eslint/no-require-imports
+        const jsClassFromModule = module[className.join('.')];
+        l1Instance = jsClassFromModule.fromCloudFormation(this, logicalId, resourceAttributes, options);
+      } else {
+        l1Instance = new core.CfnResource(this, logicalId, {
+          type: resourceAttributes.Type,
+          properties: cfnParser.parseValue(resourceAttributes.Properties),
+        });
+        cfnParser.handleAttributes(l1Instance, resourceAttributes, logicalId);
+      }
+    }
 
     if (this.preserveLogicalIds) {
       // override the logical ID to match the original template
@@ -370,7 +380,7 @@ export class CfnInclude extends core.CfnElement {
     return l1Instance;
   }
 
-  private createNestedStack(nestedStackId: string, finder: core.ICfnFinder): core.CfnResource {
+  private createNestedStack(nestedStackId: string, cfnParser: cfn_parse.CfnParser): core.CfnResource {
     const templateResources = this.template.Resources || {};
     const nestedStackAttributes = templateResources[nestedStackId] || {};
 
@@ -384,9 +394,6 @@ export class CfnInclude extends core.CfnElement {
       throw new Error('UpdatePolicy is not supported by the AWS::CloudFormation::Stack resource');
     }
 
-    const cfnParser = new cfn_parse.CfnParser({
-      finder,
-    });
     const nestedStackProps = cfnParser.parseValue(nestedStackAttributes.Properties);
     const nestedStack = new core.NestedStack(this, nestedStackId, {
       parameters: nestedStackProps.Parameters,
@@ -396,30 +403,7 @@ export class CfnInclude extends core.CfnElement {
 
     // we know this is never undefined for nested stacks
     const nestedStackResource: core.CfnResource = nestedStack.nestedStackResource!;
-    // handle resource attributes
-    const cfnOptions = nestedStackResource.cfnOptions;
-    cfnOptions.metadata = cfnParser.parseValue(nestedStackAttributes.Metadata);
-    cfnOptions.deletionPolicy = cfnParser.parseDeletionPolicy(nestedStackAttributes.DeletionPolicy);
-    cfnOptions.updateReplacePolicy = cfnParser.parseDeletionPolicy(nestedStackAttributes.UpdateReplacePolicy);
-    // handle DependsOn
-    nestedStackAttributes.DependsOn = nestedStackAttributes.DependsOn ?? [];
-    const dependencies: string[] = Array.isArray(nestedStackAttributes.DependsOn) ?
-      nestedStackAttributes.DependsOn : [nestedStackAttributes.DependsOn];
-    for (const dep of dependencies) {
-      const depResource = finder.findResource(dep);
-      if (!depResource) {
-        throw new Error(`nested stack '${nestedStackId}' depends on '${dep}' that doesn't exist`);
-      }
-      nestedStackResource.node.addDependency(depResource);
-    }
-    // handle Condition
-    if (nestedStackAttributes.Condition) {
-      const condition = finder.findCondition(nestedStackAttributes.Condition);
-      if (!condition) {
-        throw new Error(`nested stack '${nestedStackId}' uses Condition '${nestedStackAttributes.Condition}' that doesn't exist`);
-      }
-      cfnOptions.condition = condition;
-    }
+    cfnParser.handleAttributes(nestedStackResource, nestedStackAttributes, nestedStackId);
 
     const propStack = this.nestedStacksToInclude[nestedStackId];
     const template = new CfnInclude(nestedStack, nestedStackId, {

packages/@aws-cdk/cloudformation-include/test/nested-stacks.test.ts

@@ -144,7 +144,7 @@ describe('CDK Include', () => {
           },
         },
       });
-    }).toThrow(/nested stack 'ChildStack' uses Condition 'FakeCondition' that doesn't exist/);
+    }).toThrow(/Resource 'ChildStack' uses Condition 'FakeCondition' that doesn't exist/);
   });
 
   test('throws an exception when a nested stacks depends on a resource that does not exist in the template', () => {
@@ -157,7 +157,20 @@ describe('CDK Include', () => {
           },
         },
       });
-    }).toThrow(/nested stack 'ChildStack' depends on 'AFakeResource' that doesn't exist/);
+    }).toThrow(/Resource 'ChildStack' depends on 'AFakeResource' that doesn't exist/);
+  });
+
+  test('throws an exception when an ID was passed in nestedStacks that is a resource type not in the CloudFormation schema', () => {
+    expect(() => {
+      new inc.CfnInclude(stack, 'Template', {
+        templateFile: testTemplateFilePath('custom-resource.json'),
+        nestedStacks: {
+          'CustomResource': {
+            templateFile: testTemplateFilePath('whatever.json'),
+          },
+        },
+      });
+    }).toThrow(/Nested Stack with logical ID 'CustomResource' is not an AWS::CloudFormation::Stack resource/);
   });
 
   test('can modify resources in nested stacks', () => {

packages/@aws-cdk/cloudformation-include/test/test-templates/custom-resource-with-attributes.json

@@ -0,0 +1,44 @@
+{
+  "Conditions": {
+    "AlwaysFalseCond": {
+      "Fn::Equals": [
+        {
+          "Ref": "AWS::Region"
+        },
+        "completely-made-up-region"
+      ]
+    }
+  },
+  "Resources": {
+    "CustomBucket": {
+      "Type": "AWS::MyService::Custom",
+      "Condition": "AlwaysFalseCond",
+      "Metadata": {
+        "Object1": "Value1",
+        "Object2": "Value2"
+      },
+      "CreationPolicy": {
+        "AutoScalingCreationPolicy": {
+          "MinSuccessfulInstancesPercent" : 90
+        }
+      },
+      "DeletionPolicy": "Retain",
+      "DependsOn": [ "CustomResource" ]
+    },
+    "CustomResource": {
+      "Type": "AWS::MyService::AnotherCustom",
+      "Properties": {
+        "CustomProp": "CustomValue",
+        "CustomFuncProp": {
+          "Ref": "AWS::NoValue"
+        }
+      },
+      "UpdatePolicy": {
+        "AutoScalingReplacingUpdate": {
+          "WillReplace" : "false"
+        }
+      },
+      "UpdateReplacePolicy": "Retain"
+    }
+  }
+}

packages/@aws-cdk/cloudformation-include/test/test-templates/custom-resource-with-bad-condition.json

@@ -0,0 +1,8 @@
+{
+  "Resources": {
+    "CustomResource": {
+      "Type": "AWS::MyService::Custom",
+      "Condition": "AlwaysFalseCond"
+    }
+  }
+}

packages/@aws-cdk/cloudformation-include/test/test-templates/nested/custom-resource.json

@@ -0,0 +1,7 @@
+{
+  "Resources": {
+    "CustomResource": {
+      "Type": "AWS::CustomResource::Type"
+    }
+  }
+}

packages/@aws-cdk/cloudformation-include/test/valid-templates.test.ts

@@ -444,10 +444,20 @@ describe('CDK Include', () => {
     });
   });
 
-  test("throws an exception when encountering a Resource type it doesn't recognize", () => {
+  test('can include a template with a custom resource that uses attributes', () => {
+    const cfnTemplate = includeTestTemplate(stack, 'custom-resource-with-attributes.json');
+    expect(stack).toMatchTemplate(
+      loadTestFileToJsObject('custom-resource-with-attributes.json'),
+    );
+
+    const alwaysFalseCondition = cfnTemplate.getCondition('AlwaysFalseCond');
+    expect(cfnTemplate.getResource('CustomBucket').cfnOptions.condition).toBe(alwaysFalseCondition);
+  });
+
+  test("throws an exception when a custom resource uses a Condition attribute that doesn't exist in the template", () => {
     expect(() => {
-      includeTestTemplate(stack, 'non-existent-resource-type.json');
-    }).toThrow(/Unrecognized CloudFormation resource type: 'AWS::FakeService::DoesNotExist'/);
+      includeTestTemplate(stack, 'custom-resource-with-bad-condition.json');
+    }).toThrow(/Resource 'CustomResource' uses Condition 'AlwaysFalseCond' that doesn't exist/);
   });
 
   test('can ingest a template that contains outputs and modify them', () => {

packages/@aws-cdk/core/lib/cfn-parse.ts

@@ -1,5 +1,6 @@
 import { Fn } from './cfn-fn';
 import { Aws } from './cfn-pseudo';
+import { CfnResource } from './cfn-resource';
 import {
   CfnAutoScalingReplacingUpdate, CfnAutoScalingRollingUpdate, CfnAutoScalingScheduledAction, CfnCodeDeployLambdaAliasUpdate,
   CfnCreationPolicy, CfnDeletionPolicy, CfnResourceAutoScalingCreationPolicy, CfnResourceSignal, CfnUpdatePolicy,
@@ -169,7 +170,39 @@ export class CfnParser {
     this.options = options;
   }
 
-  public parseCreationPolicy(policy: any): CfnCreationPolicy | undefined {
+  public handleAttributes(resource: CfnResource, resourceAttributes: any, logicalId: string): void {
+    const finder = this.options.finder;
+    const cfnOptions = resource.cfnOptions;
+
+    cfnOptions.creationPolicy = this.parseCreationPolicy(resourceAttributes.CreationPolicy);
+    cfnOptions.updatePolicy = this.parseUpdatePolicy(resourceAttributes.UpdatePolicy);
+    cfnOptions.deletionPolicy = this.parseDeletionPolicy(resourceAttributes.DeletionPolicy);
+    cfnOptions.updateReplacePolicy = this.parseDeletionPolicy(resourceAttributes.UpdateReplacePolicy);
+    cfnOptions.metadata = this.parseValue(resourceAttributes.Metadata);
+
+    // handle Condition
+    if (resourceAttributes.Condition) {
+      const condition = finder.findCondition(resourceAttributes.Condition);
+      if (!condition) {
+        throw new Error(`Resource '${logicalId}' uses Condition '${resourceAttributes.Condition}' that doesn't exist`);
+      }
+      cfnOptions.condition = condition;
+    }
+
+    // handle DependsOn
+    resourceAttributes.DependsOn = resourceAttributes.DependsOn ?? [];
+    const dependencies: string[] = Array.isArray(resourceAttributes.DependsOn) ?
+      resourceAttributes.DependsOn : [resourceAttributes.DependsOn];
+    for (const dep of dependencies) {
+      const depResource = finder.findResource(dep);
+      if (!depResource) {
+        throw new Error(`Resource '${logicalId}' depends on '${dep}' that doesn't exist`);
+      }
+      resource.node.addDependency(depResource);
+    }
+  }
+
+  private parseCreationPolicy(policy: any): CfnCreationPolicy | undefined {
     if (typeof policy !== 'object') { return undefined; }
 
     // change simple JS values to their CDK equivalents
@@ -198,7 +231,7 @@ export class CfnParser {
     }
   }
 
-  public parseUpdatePolicy(policy: any): CfnUpdatePolicy | undefined {
+  private parseUpdatePolicy(policy: any): CfnUpdatePolicy | undefined {
     if (typeof policy !== 'object') { return undefined; }
 
     // change simple JS values to their CDK equivalents
@@ -254,7 +287,7 @@ export class CfnParser {
     }
   }
 
-  public parseDeletionPolicy(policy: any): CfnDeletionPolicy | undefined {
+  private parseDeletionPolicy(policy: any): CfnDeletionPolicy | undefined {
     switch (policy) {
       case null: return undefined;
       case undefined: return undefined;