feat(appmesh): change Route's spec to a union-like class (#11343)

Implements the same pattern `GatewayRoutes` use for defining protocol specific specs.

Adds GRPC and HTTP2 support to Routes which will resolve #9755

BREAKING CHANGE: changes Route's spec to a union-like class. RouteSpec is now defined using protocol variant static methods


----

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

packages/@aws-cdk-containers/ecs-service-extensions/lib/extensions/appmesh.ts

@@ -293,22 +293,24 @@ export class AppMeshExtension extends ServiceExtension {
       virtualRouterName: `${this.parentService.id}`,
     });
 
+    // Form the service name that requests will be made to
+    const serviceName = `${this.parentService.id}.${cloudmapNamespace.namespaceName}`;
+    const weightedTargets: appmesh.WeightedTarget[] = [{
+      virtualNode: this.virtualNode,
+      weight: 1,
+    }];
     // Now add the virtual node as a route in the virtual router
+    // Ensure that the route type matches the protocol type.
     this.route = this.virtualRouter.addRoute(`${this.parentService.id}-route`, {
-      routeTargets: [{
-        virtualNode: this.virtualNode,
-        weight: 1,
-      }],
-      // Ensure that the route type matches the protocol type.
-      routeType: this.protocol == appmesh.Protocol.HTTP ? appmesh.RouteType.HTTP : appmesh.RouteType.TCP,
+      routeSpec: this.routeSpec(weightedTargets, serviceName),
     });
 
     // Now create a virtual service. Relationship goes like this:
     // virtual service -> virtual router -> virtual node
     this.virtualService = new appmesh.VirtualService(this.scope, `${this.parentService.id}-virtual-service`, {
       mesh: this.mesh,
       virtualRouter: this.virtualRouter,
-      virtualServiceName: `${this.parentService.id}.${cloudmapNamespace.namespaceName}`,
+      virtualServiceName: serviceName,
     });
   }
 
@@ -340,6 +342,26 @@ export class AppMeshExtension extends ServiceExtension {
     this.virtualNode.addBackend(otherAppMesh.virtualService);
   }
 
+  private routeSpec(weightedTargets: appmesh.WeightedTarget[], serviceName: string): appmesh.RouteSpec {
+    switch (this.protocol) {
+      case appmesh.Protocol.HTTP: return appmesh.RouteSpec.http({
+        weightedTargets: weightedTargets,
+      });
+      case appmesh.Protocol.HTTP2: return appmesh.RouteSpec.http2({
+        weightedTargets: weightedTargets,
+      });
+      case appmesh.Protocol.GRPC: return appmesh.RouteSpec.grpc({
+        weightedTargets: weightedTargets,
+        match: {
+          serviceName: serviceName,
+        },
+      });
+      case appmesh.Protocol.TCP: return appmesh.RouteSpec.tcp({
+        weightedTargets: weightedTargets,
+      });
+    }
+  }
+
   private virtualRouterListener(port: number): appmesh.VirtualRouterListener {
     switch (this.protocol) {
       case appmesh.Protocol.HTTP: return appmesh.VirtualRouterListener.http(port);

packages/@aws-cdk/aws-appmesh/README.md

@@ -188,39 +188,63 @@ The `listeners` property can be left blank and added later with the `node.addLis
 
 A `route` is associated with a virtual router, and it's used to match requests for a virtual router and distribute traffic accordingly to its associated virtual nodes.
 
-You can use the prefix parameter in your `route` specification for path-based routing of requests. For example, if your virtual service name is my-service.local and you want the `route` to match requests to my-service.local/metrics, your prefix should be /metrics.
-
 If your `route` matches a request, you can distribute traffic to one or more target virtual nodes with relative weighting.
 
 ```typescript
-router.addRoute('route', {
-  routeTargets: [
-    {
-      virtualNode,
-      weight: 1,
+router.addRoute('route-http', {
+  routeSpec: appmesh.RouteSpec.http({
+    weightedTargets: [
+      {
+        virtualNode: node,
+      },
+    ],
+    match: {
+      prefixPath: '/path-to-app',
     },
-  ],
-  prefix: `/path-to-app`,
-  routeType: RouteType.HTTP,
+  }),
 });
 ```
 
 Add a single route with multiple targets and split traffic 50/50
 
 ```typescript
-router.addRoute('route', {
-  routeTargets: [
-    {
-      virtualNode,
-      weight: 50,
+router.addRoute('route-http', {
+  routeSpec: appmesh.RouteSpec.http({
+    weightedTargets: [
+      {
+        virtualNode: node,
+        weight: 50,
+      },
+      {
+        virtualNode: node,
+        weight: 50,
+      },
+    ],
+    match: {
+      prefixPath: '/path-to-app',
     },
-    {
-      virtualNode2,
-      weight: 50,
+  }),
+});
+```
+
+The _RouteSpec_ class provides an easy interface for defining new protocol specific route specs.
+The `tcp()`, `http()` and `http2()` methods provide the spec necessary to define a protocol specific spec.
+
+For HTTP based routes, the match field can be used to match on a route prefix.
+By default, an HTTP based route will match on `/`. All matches must start with a leading `/`.
+
+```typescript
+router.addRoute('route-http', {
+  routeSpec: appmesh.RouteSpec.grpc({
+    weightedTargets: [
+      {
+        virtualNode: node,
+      },
+    ],
+    match: {
+      serviceName: 'my-service.default.svc.cluster.local',
     },
-  ],
-  prefix: `/path-to-app`,
-  routeType: RouteType.HTTP,
+  }),
 });
 ```
 

packages/@aws-cdk/aws-appmesh/lib/index.ts

@@ -2,6 +2,7 @@
 export * from './appmesh.generated';
 export * from './mesh';
 export * from './route';
+export * from './route-spec';
 export * from './shared-interfaces';
 export * from './virtual-node';
 export * from './virtual-router';