feat: Implement gRPC Reflection Service (#340)

Co-authored-by: Samani G. Gikandi <[email protected]>

examples/Cargo.toml

@@ -130,6 +130,10 @@ path = "src/hyper_warp/server.rs"
 name = "health-server"
 path = "src/health/server.rs"
 
+[[bin]]
+name = "reflection-server"
+path = "src/reflection/server.rs"
+
 [[bin]]
 name = "autoreload-server"
 path = "src/autoreload/server.rs"
@@ -173,6 +177,8 @@ http-body = "0.4"
 pin-project = "1.0"
 # Health example
 tonic-health = { path = "../tonic-health" }
+# Reflection example
+tonic-reflection = { path = "../tonic-reflection" }
 listenfd = "0.3"
 
 [build-dependencies]

examples/README.md

@@ -94,6 +94,13 @@ $ cargo run --bin tls-server
 $ cargo run --bin health-server
 ```
 
+## Server Reflection
+
+### Server
+```bash
+$ cargo run --bin reflection-server
+```
+
 ## Tower Middleware
 
 ### Server

examples/build.rs

@@ -1,10 +1,18 @@
+use std::env;
+use std::path::PathBuf;
+
 fn main() {
     tonic_build::configure()
         .type_attribute("routeguide.Point", "#[derive(Hash)]")
         .compile(&["proto/routeguide/route_guide.proto"], &["proto"])
         .unwrap();
 
-    tonic_build::compile_protos("proto/helloworld/helloworld.proto").unwrap();
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+    tonic_build::configure()
+        .file_descriptor_set_path(out_dir.join("helloworld_descriptor.bin"))
+        .compile(&["proto/helloworld/helloworld.proto"], &["proto"])
+        .unwrap();
+
     tonic_build::compile_protos("proto/echo/echo.proto").unwrap();
 
     tonic_build::configure()

examples/src/reflection/server.rs

@@ -0,0 +1,46 @@
+use tonic::transport::Server;
+use tonic::{Request, Response, Status};
+
+mod proto {
+    tonic::include_proto!("helloworld");
+
+    pub(crate) const FILE_DESCRIPTOR_SET: &'static [u8] =
+        tonic::include_file_descriptor_set!("helloworld_descriptor");
+}
+
+#[derive(Default)]
+pub struct MyGreeter {}
+
+#[tonic::async_trait]
+impl proto::greeter_server::Greeter for MyGreeter {
+    async fn say_hello(
+        &self,
+        request: Request<proto::HelloRequest>,
+    ) -> Result<Response<proto::HelloReply>, Status> {
+        println!("Got a request from {:?}", request.remote_addr());
+
+        let reply = proto::HelloReply {
+            message: format!("Hello {}!", request.into_inner().name),
+        };
+        Ok(Response::new(reply))
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let service = tonic_reflection::server::Builder::configure()
+        .register_encoded_file_descriptor_set(proto::FILE_DESCRIPTOR_SET)
+        .build()
+        .unwrap();
+
+    let addr = "[::1]:50052".parse().unwrap();
+    let greeter = MyGreeter::default();
+
+    Server::builder()
+        .add_service(service)
+        .add_service(proto::greeter_server::GreeterServer::new(greeter))
+        .serve(addr)
+        .await?;
+
+    Ok(())
+}