Proxy gRPC Traffic

Google Remote Procedure Call (gRPC) is an open-source, high-performance RPC framework built on the HTTP/2 protocol and using Protocol Buffers (protobuf) as its Interface Description Language (IDL).

This guide will show you how to configure the gateway to proxy gRPC traffic using the Ingress Controller.

Prerequisites

1. Complete Set Up Ingress Controller and Gateway.
2. Install gRPCurl to verify gRPC traffic proxying.

Start an Example Upstream Service

Create a Kubernetes manifest file for the gRPC server deployment and service:

apiVersion: apps/v1
kind: Deployment
metadata:
  namespace: aic
  name: grpc-service
spec:
  replicas: 1
  selector:
    matchLabels:
      app: grpc-service
  template:
    metadata:
      labels:
        app: grpc-service
    spec:
      containers:
        - name: grpc-service
          image: api7/grpc-server-example:1.0.0
          ports:
            - containerPort: 50051
---
apiVersion: v1
kind: Service
metadata:
  namespace: aic
  name: grpc-service
spec:
  type: ClusterIP
  selector:
    app: grpc-service
  ports:
    - name: grpc
      port: 50051
      targetPort: 50051

Apply the configuration to your cluster:

kubectl apply -f grpc-server.yaml

To verify whether the gRPC server is running, first, port forward the gRPC server's service port to your local machine:

kubectl port-forward svc/grpc-service 50051:50051 &

Send a request to the service to list all available gRPC services and methods:

grpcurl -plaintext 127.0.0.1:50051 list

If everything is ok, you should see the following response:

grpc.reflection.v1alpha.ServerReflection
helloworld.Greeter
helloworld.TestImport

List all the available methods for the helloworld.Greeter service:

grpcurl -plaintext 127.0.0.1:50051 list helloworld.Greeter

If everything is ok, you should see the following response:

helloworld.Greeter.GetErrResp
helloworld.Greeter.Plus
helloworld.Greeter.SayHello
helloworld.Greeter.SayHelloAfterDelay
helloworld.Greeter.SayHelloBidirectionalStream
helloworld.Greeter.SayHelloClientStream
helloworld.Greeter.SayHelloServerStream

Create a Route

apiVersion: gateway.networking.k8s.io/v1
kind: GRPCRoute
metadata:
  namespace: aic
  name: grpc-route
spec:
  parentRefs:
  - name: apisix
  rules:
  - matches:
    - method:
        service: helloworld.Greeter
        method: SayHello
    backendRefs:
    - name: grpc-service
      port: 50051

apiVersion: apisix.apache.org/v2
kind: ApisixUpstream
metadata:
  namespace: aic
  name: grpc-service
spec:
  ingressClassName: apisix
  scheme: grpc
---
apiVersion: apisix.apache.org/v2
kind: ApisixRoute
metadata:
  namespace: aic
  name: grpc-route
spec:
  ingressClassName: apisix
  http:
    - name: helloworld-greeter
      match:
        paths:
          - /helloworld.Greeter/SayHello
        methods:
          - GET
          - POST
      backends:
        - serviceName: grpc-service
          servicePort: 50051

Apply the configurations to your cluster:

kubectl apply -f grpc-route.yaml

Update Gateway Configuration for HTTP/2

By default, the gateway supports TLS-encrypted HTTP/2 on port 9443. For non-encrypted HTTP/2, you can add a new port to the gateway configuration.

In this section, you will be updating the gateway configuration and deployment to support non-encrypted HTTP/2 on 9081.

helm get values -n aic apisix --all > values.yaml

service:
  http:
    containerPort: 9080
    enabled: true
    servicePort: 80
    additionalContainerPorts:
      - port: 9081
        enable_http2: true

helm upgrade -n aic apisix apisix/apisix -f values.yaml

helm get values -n aic api7-ee-3-gateway --all > values.yaml

gateway:
  http:
    enabled: true
    ip: 0.0.0.0
    servicePort: 80
    containerPort: 9080
    additionalContainerPorts:
      - port: 9081
        enable_http2: true

helm upgrade --install -n aic api7-ee-3-gateway api7/gateway -f values.yaml

Verify

Download the helloworld.proto file here.

This example uses the helloworld.proto file to ensure the gRPCurl CLI tool aligns the request and response format with the gRPC service definition.

Expose the gateway’s HTTP/2 service port to your local machine:

# replace with your gateway’s service name
kubectl port-forward svc/<gateway-service-name> 9081:9081 &

Send a request to the route:

grpcurl -plaintext \
  -proto helloworld.proto \
  -d '{"name":"World"}' \
  "127.0.0.1:9081" \
  "helloworld.Greeter.SayHello"

You should see the following output:

{
  "message": "Hello World"
}