(AppMesh): How to create two virtual service/node with bidirectional backend without circular dependencies

What is the problem?

I am currently setting up a CDK stack using ECS and AppMesh to create a micro service environment. In this micro service environment, every service should be able to talk to every other service. What I am trying to do is create a VirtualNode & Service per micro service and then call addBackend for each of these services and add all other services. However, this creates a cyclic dependencies for all services.

I haven’t found a way yet to create this bidirectional backend setup without creating cyclic dependencies inside the CDK.

Reproduction Steps

        // Inside 1 stack
        const node1 = new appmesh.VirtualNode(stack1, 'node1', {
            virtualNodeName: 'Node1',
            mesh: props.mesh,
            listeners: [appmesh.VirtualNodeListener.grpc({
                port: 8080,
                healthCheck: appmesh.HealthCheck.grpc({
                    healthyThreshold: 2,
                    interval: cdk.Duration.seconds(5),
                    timeout: cdk.Duration.seconds(2),
                    unhealthyThreshold: 3,
                }),
            })],
            accessLog: appmesh.AccessLog.fromFilePath('/dev/stdout'),
        });

        const service1 = new appmesh.VirtualService(stack2, 'Service1', {
            virtualServiceName:  'Service1',
            virtualServiceProvider: appmesh.VirtualServiceProvider.virtualNode(node1),
        });

       // Inside stack 2
        const node2 = new appmesh.VirtualNode(this, 'node2', {
            virtualNodeName: 'Node2',
            mesh: props.mesh,
            listeners: [appmesh.VirtualNodeListener.grpc({
                port: 8080,
                healthCheck: appmesh.HealthCheck.grpc({
                    healthyThreshold: 2,
                    interval: cdk.Duration.seconds(5),
                    timeout: cdk.Duration.seconds(2),
                    unhealthyThreshold: 3,
                }),
            })],
            accessLog: appmesh.AccessLog.fromFilePath('/dev/stdout'),
        });

        const service2 = new appmesh.VirtualService(this, 'Service2', {
            virtualServiceName: 'Service2',
            virtualServiceProvider: appmesh.VirtualServiceProvider.virtualNode(node2),
        });

      // Added afterwards via Aspect
      node1.addBackend(service2);
      node2.addBackend(service1)

What did you expect to happen?

I expected there to be a way to create a bidirectional connection between backend services.

What actually happened?

It always creates a circular dependency and I can’t see any escape hatch

CDK CLI Version

1.130.0

Framework Version

No response

Node.js Version

9.0.0

OS

MacOS BigSur

Language

Typescript

Language Version

No response

Other information

No response

[wplucinsky]

A new version of @aws-cdk/aws-appmesh has been published to NPM. Versions >= 1.139.0 contain the fix.

[ashanpw]

Thanks for the info. We are able to reproduce the issue and are now figuring out how to fix this or provide a workaround.