From dd01a409a0225c436dbba5699531d8ea3b4f4be9 Mon Sep 17 00:00:00 2001
From: wplucinsky <wplucinsky@gmail.com>
Date: Fri, 26 Nov 2021 10:37:21 -0800
Subject: [PATCH] allow the virtualServiceName field for virtual node backends
 to be supplied as a string

---
 packages/@aws-cdk/aws-appmesh/README.md       |  8 ++--
 .../aws-appmesh/lib/shared-interfaces.ts      | 36 +++++++++++++++
 .../aws-appmesh/test/virtual-node.test.ts     | 45 +++++++++++++++++++
 3 files changed, 85 insertions(+), 4 deletions(-)

diff --git a/packages/@aws-cdk/aws-appmesh/README.md b/packages/@aws-cdk/aws-appmesh/README.md
index 54bc79fade4c3..65a974a2fe7ad 100644
--- a/packages/@aws-cdk/aws-appmesh/README.md
+++ b/packages/@aws-cdk/aws-appmesh/README.md
@@ -203,6 +203,7 @@ declare const mesh: appmesh.Mesh;
 declare const router: appmesh.VirtualRouter;
 declare const service: cloudmap.Service;
 
+const virtualServiceName = 'service1.domain.local';
 const node = new appmesh.VirtualNode(this, 'node', {
   mesh,
   serviceDiscovery: appmesh.ServiceDiscovery.cloudMap(service),
@@ -218,21 +219,20 @@ const node = new appmesh.VirtualNode(this, 'node', {
     timeout: {
       idle: cdk.Duration.seconds(5),
     },
+    backends: [appmesh.Backend.virtualServiceName(virtualServiceName)]
   })],
   accessLog: appmesh.AccessLog.fromFilePath('/dev/stdout'),
 });
 
 const virtualService = new appmesh.VirtualService(this, 'service-1', {
   virtualServiceProvider: appmesh.VirtualServiceProvider.virtualRouter(router),
-  virtualServiceName: 'service1.domain.local',
+  virtualServiceName,
 });
-
-node.addBackend(appmesh.Backend.virtualService(virtualService));
 ```
 
 The `listeners` property can be left blank and added later with the `node.addListener()` method. The `serviceDiscovery` property must be specified when specifying a listener.
 
-The `backends` property can be added with `node.addBackend()`. In the example, we define a virtual service and add it to the virtual node to allow egress traffic to other nodes.
+The `backends` property can be added in the constructor or with `node.addBackend()`. In the example, we define a virtual service and add it to the virtual node to allow egress traffic to other nodes.
 
 The `backendDefaults` property is added to the node while creating the virtual node. These are the virtual node's default settings for all backends.
 
diff --git a/packages/@aws-cdk/aws-appmesh/lib/shared-interfaces.ts b/packages/@aws-cdk/aws-appmesh/lib/shared-interfaces.ts
index 8e672ac535bdc..0a7bc9b6a86b7 100644
--- a/packages/@aws-cdk/aws-appmesh/lib/shared-interfaces.ts
+++ b/packages/@aws-cdk/aws-appmesh/lib/shared-interfaces.ts
@@ -215,6 +215,13 @@ export abstract class Backend {
     return new VirtualServiceBackend(virtualService, props.tlsClientPolicy);
   }
 
+  /**
+   * Construct a Virtual Service backend via a Virtual Service name
+   */
+  public static virtualServiceName(virtualServiceName: string, props: VirtualServiceBackendOptions = {}): Backend {
+    return new VirtualServiceNameBackend(virtualServiceName, props.tlsClientPolicy);
+  }
+
   /**
    * Return backend config
    */
@@ -250,6 +257,35 @@ class VirtualServiceBackend extends Backend {
   }
 }
 
+/**
+ * Represents the properties needed to define a Virtual Service backend via a Virtual Service name
+ */
+class VirtualServiceNameBackend extends Backend {
+
+  constructor (private readonly virtualServiceName: string,
+    private readonly tlsClientPolicy: TlsClientPolicy | undefined) {
+    super();
+  }
+
+  /**
+   * Return config for a Virtual Service backend
+   */
+  public bind(scope: Construct): BackendConfig {
+    return {
+      virtualServiceBackend: {
+        virtualService: {
+          virtualServiceName: this.virtualServiceName,
+          clientPolicy: this.tlsClientPolicy
+            ? {
+              tls: renderTlsClientPolicy(scope, this.tlsClientPolicy),
+            }
+            : undefined,
+        },
+      },
+    };
+  }
+}
+
 /**
  * Connection pool properties for HTTP listeners
  */
diff --git a/packages/@aws-cdk/aws-appmesh/test/virtual-node.test.ts b/packages/@aws-cdk/aws-appmesh/test/virtual-node.test.ts
index 82bc98c6267ef..43c015fc1328e 100644
--- a/packages/@aws-cdk/aws-appmesh/test/virtual-node.test.ts
+++ b/packages/@aws-cdk/aws-appmesh/test/virtual-node.test.ts
@@ -57,8 +57,53 @@ describe('virtual node', () => {
           },
           MeshOwner: ABSENT,
         });
+      });
+
+      test('should add resource with service backends via virtual service names', () => {
+        // GIVEN
+        const stack = new cdk.Stack();
+
+        // WHEN
+        const mesh = new appmesh.Mesh(stack, 'mesh', {
+          meshName: 'test-mesh',
+        });
+
+        const service1Name = 'service1.domain.local';
+        new appmesh.VirtualService(stack, 'service-1', {
+          virtualServiceName: service1Name,
+          virtualServiceProvider: appmesh.VirtualServiceProvider.none(mesh),
+        });
+        const service2Name = 'service2.domain.local';
+        new appmesh.VirtualService(stack, 'service-2', {
+          virtualServiceName: service2Name,
+          virtualServiceProvider: appmesh.VirtualServiceProvider.none(mesh),
+        });
+
+        const node = new appmesh.VirtualNode(stack, 'test-node', {
+          mesh,
+          serviceDiscovery: appmesh.ServiceDiscovery.dns('test'),
+          backends: [appmesh.Backend.virtualServiceName(service1Name)],
+        });
 
+        node.addBackend(appmesh.Backend.virtualServiceName(service2Name));
 
+        // THEN
+        expect(stack).toHaveResourceLike('AWS::AppMesh::VirtualNode', {
+          Spec: {
+            Backends: [
+              {
+                VirtualService: {
+                  VirtualServiceName: service1Name,
+                },
+              },
+              {
+                VirtualService: {
+                  VirtualServiceName: service2Name,
+                },
+              },
+            ],
+          },
+        });
       });
     });