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

Navigate to this directory:

cd grpc/examples/python/xds

Run the server

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

Run the Client

Set up xDS configuration.

After configuring your xDS server to track the gRPC server we just started, create a bootstrap file as described 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>
}

Point the GRPC_XDS_BOOTSTRAP environment variable at the bootstrap file:

export GRPC_XDS_BOOTSTRAP=/etc/xds-bootstrap.json

Run the client:

python client.py xds:///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.

Verify the server's application-layer service:

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

Verify that all services are available via reflection:

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

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"
}

Running with Proxyless Security

Run the Server with Secure Credentials

Add the --secure true flag to the invocation outlined above.

python server.py --secure true

Run the Client with Secure Credentials

Add the --secure true flag to the invocation outlined above.

Run the client:

python client.py xds:///my-backend --secure true

Building Docker

From the gRPC workspace folder:

Client:

docker build -f examples/python/xds/Dockerfile.client -t "${xds-example-python-client-tag}" .

Server:

docker build -f examples/python/xds/Dockerfile.server -t "${xds-example-python-server-tag}" .

And then push the tagged image using docker push.

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