grpc/examples/python/xds/README.md

gRPC Hostname Example

The hostname example is a Hello World server whose response includes its hostname. It also supports health and reflection services. This makes it a good server to test infrastructure, like load balancing. This example depends on a gRPC version of 1.28.1 or newer.

Run the Server

1. Navigate to this directory:

   cd grpc/examples/python/xds
   

2. Run the server

   virtualenv venv -p python3
   source venv/bin/activate
   pip install -r requirements.txt
   python server.py
   

Run the Client

1. Set up xDS configuration.

After configuring your xDS server to track the gRPC server we just started, create a bootstrap file as desribed in gRFC A27:

{
  xds_servers": [
    {
      "server_uri": <string containing URI of xds server>,
      "channel_creds": [
        {
          "type": <string containing channel cred type>,
          "config": <JSON object containing config for the type>
        }
      ]
    }
  ],
  "node": <JSON form of Node proto>
}

1. Point the GRPC_XDS_BOOTSTRAP environment variable at the bootstrap file:

   export GRPC_XDS_BOOTSTRAP=/etc/xds-bootstrap.json
   

2. Run the client:

   python client.py xds-experimental:///my-backend
   

Verifying Configuration with a CLI Tool

Alternatively, grpcurl can be used to verify your server. If you don't have it, install grpcurl. This will allow you to manually test the service.

Be sure to set up the bootstrap file and GRPC_XDS_BOOTSTRAP as in the previous section.

1. Verify the server's application-layer service:

   > grpcurl --plaintext -d '{"name": "you"}' localhost:50051
   {
   "message": "Hello you from rbell.svl.corp.google.com!"
   }
   

2. Verify that all services are available via reflection:

   > grpcurl --plaintext localhost:50051 list
   grpc.health.v1.Health
   grpc.reflection.v1alpha.ServerReflection
   helloworld.Greeter
   

3. Verify that all services are reporting healthy:

   > grpcurl --plaintext -d '{"service": "helloworld.Greeter"}' localhost:50051
   grpc.health.v1.Health/Check
   {
   "status": "SERVING"
   }
   
   > grpcurl --plaintext -d '{"service": ""}' localhost:50051
   grpc.health.v1.Health/Check
   {
   "status": "SERVING"
   }