feat(grpc): Add basic grpc example

Cargo.toml

@@ -6,3 +6,9 @@ edition = "2021"
 [dependencies]
 clap = { version = "4.5.4", features = ["derive"] }
 ignore = "0.4.22"
+prost = "0.12.4"
+tokio = { version = "1", features = ["full"] }
+tonic = "0.11.0"
+
+[build-dependencies]
+tonic-build = "0.11.0"

build.rs

@@ -0,0 +1,5 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::compile_protos("proto/helloworld.proto")?;
+
+    Ok(())
+}

proto/helloworld.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+package helloworld;
+
+service Greater {
+  rpc SayHello (HelloRequest) returns (HelloResponse);
+}
+
+message HelloRequest {
+  string name = 1;
+}
+
+message HelloResponse {
+  string message = 1;
+}

src/grpc.rs

@@ -0,0 +1,37 @@
+use std::error::Error;
+use std::net::{SocketAddr, TcpListener};
+
+use tonic::async_trait;
+
+use self::client::GRPCClient;
+use self::server::GRPCServer;
+
+mod client;
+mod server;
+
+pub mod hello_world {
+    tonic::include_proto!("helloworld");
+}
+
+#[async_trait]
+pub trait Connection {
+    async fn connect(&self) -> Result<(), Box<dyn Error>>;
+}
+
+fn is_socket_in_use(addr: String) -> bool {
+    let socket: SocketAddr = addr.parse().expect("Failed to create socket");
+    match TcpListener::bind(socket) {
+        Ok(_) => true,
+        Err(_) => false,
+    }
+}
+
+pub fn run() -> Result<Box<dyn Connection>, Box<dyn Error>> {
+    let addr = "[::1]:50051";
+
+    if is_socket_in_use(addr.to_string()) {
+        Ok(Box::new(GRPCServer::new(addr.to_string())))
+    } else {
+        Ok(Box::new(GRPCClient::new(addr.to_string())))
+    }
+}

src/grpc/client.rs

@@ -0,0 +1,33 @@
+use super::hello_world;
+
+use hello_world::greater_client::GreaterClient;
+use hello_world::HelloRequest;
+use tonic::async_trait;
+
+#[derive(Debug, Default)]
+pub struct GRPCClient {
+    address: String,
+}
+
+impl GRPCClient {
+    pub fn new(address: String) -> Self {
+        Self { address }
+    }
+}
+
+#[async_trait]
+impl super::Connection for GRPCClient {
+    async fn connect(&self) -> Result<(), Box<dyn std::error::Error>> {
+        let mut client = GreaterClient::connect(format!("http://{}", self.address)).await?;
+
+        let request = tonic::Request::new(HelloRequest {
+            name: "Self".into(),
+        });
+
+        let response = client.say_hello(request).await?;
+
+        println!("RESPONSE={:?}", response);
+
+        Ok(())
+    }
+}

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(())
+    }
+}

src/main.rs

@@ -1,8 +1,10 @@
 use std::{env, path::PathBuf};
 
 use clap::Parser;
+use std::error::Error;
 
 mod file_explorer;
+mod grpc;
 
 #[derive(Parser)]
 #[command(version, about, long_about = None)]
@@ -11,7 +13,8 @@ struct Args {
     path: Option<PathBuf>,
 }
 
-fn main() {
+#[tokio::main()]
+async fn main() -> Result<(), Box<dyn Error>> {
     let cli = Args::parse();
     let path = cli
         .path
@@ -19,5 +22,11 @@ fn main() {
 
     let files = file_explorer::walk_dir(&path).expect("error");
 
-    eprintln!("DEBUGPRINT[4]: main.rs:20: files={:#?}", files);
+    eprintln!("DEBUGPRINT[4]: main.rs:20: files={:#?}", files.len());
+
+    let server = grpc::run()?;
+
+    server.connect().await?;
+
+    Ok(())
 }