For this sample, we've already generated the server and client stubs from [helloworld.proto](https://github.com/grpc/grpc-common/blob/master/protos/helloworld.proto).
For this sample, we've already generated the server and client stubs from [helloworld.proto][]
PREREQUISITES
-------------
- Ruby 2.x
This requires Ruby 2.x, as the gRPC API surface uses keyword args.
If you don't have that installed locally, you can use [RVM](https://www.rvm.io/) to use Ruby 2.x for testing without upgrading the version of Ruby on your whole system.
If you don't have that installed locally, you can use [RVM][] to use Ruby 2.x for testing without upgrading the version of Ruby on your whole system.
RVM is also useful if you don't have the necessary privileges to update your system's Ruby.
```sh
$ # RVM installation as specified at https://rvm.io/rvm/install