gRPC Routing

This document describes setting up gRPC routing in FSM Gateway with GRPCRoute, focusing on directing traffic based on service and method.

The GRPCRoute is used to route gRPC request to backend service. It can match requests by hostname, gRPC service, gRPC method, or HTTP/2 header.

Prerequisites

  • Kubernetes cluster version v1.21.0 or higher.
  • kubectl CLI
  • FSM Gateway installed via guide doc.

Demonstration

Deploy sample

kubectl create namespace grpcbin
kubectl apply -n grpcbin -f https://raw.githubusercontent.com/flomesh-io/fsm-docs/main/manifests/gateway/gprc-routing.yaml

In gRPC case, the listener configuration is similar with HTTP routing.

gRPC Route

We configure the match rule using service: hello.HelloService and method: SayHello to direct traffic to the target service.

rules:
- matches:
  - method:
      service: hello.HelloService
      method: SayHello
  backendRefs:
  - name: grpcbin
    port: 9000

Let’s test our configuration now.

Test

To test gRPC service, we will test with help of the tool grpcurl.

Let’s record the IP address of gateway first.

export GATEWAY_IP=$(kubectl get svc -n grpcbin -l app=fsm-gateway -o jsonpath='{.items[0].status.loadBalancer.ingress[0].ip}')

Issue a request using the grpcurl command, specifying the service name and method. Doing so will yield the correct response.

grpcurl -plaintext -d '{"greeting":"Flomesh"}' $GATEWAY_IP:8000 hello.HelloService/SayHello
{
  "reply": "hello Flomesh"
}

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