gRPC Routing Example

In this example, we deploy NGINX Gateway Fabric, a simple gRPC web application, and then configure NGINX Gateway Fabric to route traffic to that application using GRPCRoute resources.

Running the Example

1. Deploy NGINX Gateway Fabric

1. Follow the installation instructions to deploy NGINX Gateway Fabric.

2. Save the public IP address of NGINX Gateway Fabric into a shell variable:

   GW_IP=XXX.YYY.ZZZ.III
   

3. Save the port of NGINX Gateway Fabric:

   GW_PORT=<port number>
   

2. Deploy the Helloworld Application

1. Create the two helloworld Deployments and Services:

   kubectl apply -f helloworld.yaml

2. Check that the Pods are running in the default Namespace:

   kubectl -n default get pods

   NAME                      READY   STATUS    RESTARTS   AGE
   grpc-infra-backend-v1-766c7d6788-rg92p   1/1     Running   0          12s
   grpc-infra-backend-v2-546f7c8d48-mjkkx   1/1     Running   0          12s
   

   Save these pod names into variables:

   POD_V1=<grpc-infra-backend-v1-xxxxxxxxxx-xxxxx>
   POD_V2=<grpc-infra-backend-v2-xxxxxxxxxx-xxxxx>
   

3. Configure Routing

There are 3 options to configure gRPC routing. To access the application and test the routing rules, we will use grpcurl.

3a. Configure exact method matching based routing

1. Create the Gateway and GRPCRoute resources:

   kubectl apply -f exact-method.yaml

2. Test the Application:

   grpcurl -plaintext -proto grpc.proto -authority bar.com -d '{"name": "exact"}' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
       "message": "Hello exact"
   }
   

3. Clean up the Gateway and GRPCRoute resources:

   kubectl delete -f exact-method.yaml

3b. Configure hostname based routing

1. Create the Gateway and GRPCRoute resources:

   kubectl apply -f hostname.yaml

2. Test the Application:

   grpcurl -plaintext -proto grpc.proto -authority bar.com -d '{"name": "bar server"}' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
       "message": "Hello bar server"
   }
   

   To make sure this came from the correct server, we can check the application server logs:

   kubectl logs ${POD_V1}

   2024/04/29 09:26:54 server listening at [::]:50051
   2024/04/29 09:28:54 Received: bar server
   

   Now we'll send a request to foo.bar.com

   grpcurl -plaintext -proto grpc.proto -authority foo.bar.com -d '{"name": "foo bar server"}' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
       "message": "Hello foo bar server"
   }
   

   This time, we'll check the POD_V2 logs:

   kubectl logs ${POD_V2}

   2024/04/29 09:26:55 server listening at [::]:50051
   2024/04/29 09:29:46 Received: foo bar server
   

3. Clean up the Gateway and GRPCRoute resources:

   kubectl delete -f hostname.yaml

3c. Configure headers based routing

1. Create the Gateway and GRPCRoute resources:

   kubectl apply -f headers.yaml

2. Test the Application:

   grpcurl -plaintext -proto grpc.proto -authority bar.com -d '{"name": "version one"}' -H 'version: one' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
       "message": "Hello version one"
   }
   

   To make sure this came from the correct server, we can check the application server logs:

   kubectl logs ${POD_V1}

   <...>
   2024/04/29 09:30:27 Received: version one
   

   Now we'll send a request with the header version: two

   grpcurl -plaintext -proto grpc.proto -authority bar.com -d '{"name": "version two"}' -H 'version: two' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
       "message": "Hello version two"
   }
   

   This time, we'll check the POD_V2 logs:

   kubectl logs ${POD_V2}

   <...>
   2024/04/29 09:32:46 Received: version two
   

   Finally, we'll send a request with the headers version: two and color: orange

   grpcurl -plaintext -proto grpc.proto -authority bar.com -d '{"name": "version two orange"}' -H 'version: two' -H 'color: orange' ${GW_IP}:${GW_PORT} helloworld.Greeter/SayHello

   {
     "message": "Hello version two orange"
   }
   

   Now check the POD_V1 logs again:

   kubectl logs ${POD_V1}

   <...>
   2024/04/29 09:30:27 Received: version one
   2024/04/29 09:33:26 Received: version two orange
   

3. Clean up the Gateway and GRPCRoute resources:

   kubectl delete -f headers.yaml