feat(grpc): Add basic grpc example

src/grpc/server.rs

@@ -0,0 +1,50 @@
+use super::hello_world;
+use hello_world::greater_server::{Greater, GreaterServer};
+use hello_world::{HelloRequest, HelloResponse};
+use std::error::Error;
+use std::net::SocketAddr;
+use tonic::transport::Server;
+use tonic::{async_trait, Request, Response, Result, Status};
+
+#[derive(Debug, Default)]
+pub struct GRPCServer {
+    address: String,
+}
+
+impl GRPCServer {
+    pub fn new(address: String) -> Self {
+        Self { address }
+    }
+}
+
+#[tonic::async_trait]
+impl Greater for GRPCServer {
+    async fn say_hello(
+        &self,
+        request: Request<HelloRequest>,
+    ) -> Result<Response<HelloResponse>, Status> {
+        println!("Got a request {:?}", request);
+
+        let reply = hello_world::HelloResponse {
+            message: format!("Hello {}!", request.into_inner().name),
+        };
+
+        Ok(Response::new(reply))
+    }
+}
+
+#[async_trait]
+impl super::Connection for GRPCServer {
+    async fn connect(&self) -> Result<(), Box<dyn Error>> {
+        println!("Starting server on: \"{}\"", self.address);
+
+        let socket: SocketAddr = self.address.parse()?;
+
+        Server::builder()
+            .add_service(GreaterServer::new(GRPCServer::default()))
+            .serve(socket)
+            .await?;
+
+        Ok(())
+    }
+}