generate code:
python -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. greetings.proto
npm install -g grpc-tools
npm install @grpc/grpc-js
grpc_tools_node_protoc --js_out=import_style=commonjs,binary:. --grpc_out=. --plugin=protoc-gen-grpc=`which grpc_tools_node_protoc_plugin` greetings.proto
run in separate terminals:
python server.py
node client.js