Thread beacon node RPC server

beacon_node/rpc/src/lib.rs

@@ -9,24 +9,28 @@ use self::beacon_chain::BeaconChain;
 use self::beacon_node::BeaconNodeServiceInstance;
 use self::validator::ValidatorServiceInstance;
 pub use config::Config as RPCConfig;
+use futures::{future, Future};
 use grpcio::{Environment, Server, ServerBuilder};
 use protos::services_grpc::{
     create_beacon_block_service, create_beacon_node_service, create_validator_service,
 };
+use slog::{info, o, warn};
 use std::sync::Arc;
-
-use slog::{info, o};
+use tokio::runtime::TaskExecutor;
 
 pub fn start_server(
     config: &RPCConfig,
+    executor: &TaskExecutor,
     beacon_chain: Arc<BeaconChain>,
     log: &slog::Logger,
-) -> Server {
+) -> exit_future::Signal {
     let log = log.new(o!("Service"=>"RPC"));
     let env = Arc::new(Environment::new(1));
 
-    // build the individual rpc services
+    // build a channel to kill the rpc server
+    let (rpc_exit_signal, rpc_exit) = exit_future::signal();
 
+    // build the individual rpc services
     let beacon_node_service = {
         let instance = BeaconNodeServiceInstance {
             chain: beacon_chain.clone(),
@@ -50,9 +54,22 @@ pub fn start_server(
         .bind(config.listen_address.to_string(), config.port)
         .build()
         .unwrap();
-    server.start();
-    for &(ref host, port) in server.bind_addrs() {
-        info!(log, "gRPC listening on {}:{}", host, port);
-    }
-    server
+
+    let spawn_rpc = {
+        server.start();
+        for &(ref host, port) in server.bind_addrs() {
+            info!(log, "gRPC listening on {}:{}", host, port);
+        }
+        rpc_exit.and_then(move |_| {
+            info!(log, "RPC Server shutting down");
+            server
+                .shutdown()
+                .wait()
+                .map(|_| ())
+                .map_err(|e| warn!(log, "RPC server failed to shutdown: {:?}", e))?;
+            Ok(())
+        })
+    };
+    executor.spawn(spawn_rpc);
+    rpc_exit_signal
 }