Handle errors when starting parity (#1451)

signer/src/ws_server/mod.rs

@@ -110,7 +110,17 @@ impl Server {
 		// Spawn a thread with event loop
 		let handle = thread::spawn(move || {
 			ph.catch_panic(move || {
-				ws.listen(addr).unwrap()
+				match ws.listen(addr).map_err(ServerError::from) {
+					Err(ServerError::IoError(io)) => die(format!(
+						"Signer: Could not start listening on specified address. Make sure that no other instance is running on Signer's port. Details: {:?}",
+						io
+					)),
+					Err(any_error) => die(format!(
+						"Signer: Unknown error occured when starting Signer. Details: {:?}",
+						any_error
+					)),
+					Ok(server) => server,
+				}
 			}).unwrap()
 		});
 
@@ -123,7 +133,11 @@ impl Server {
 					// TODO [ToDr] Some better structure here for messages.
 					broadcaster.send("new_message").unwrap();
 				}).expect("It's the only place we are running start_listening. It shouldn't fail.");
-				broadcaster.shutdown().expect("Broadcaster should close gently.")
+				let res = broadcaster.shutdown();
+
+				if let Err(e) = res {
+					warn!("Signer: Broadcaster was not closed cleanly. Details: {:?}", e);
+				}
 			}).unwrap()
 		});
 
@@ -148,5 +162,11 @@ impl Drop for Server {
 		self.queue.finish();
 		self.broadcaster_handle.take().unwrap().join().unwrap();
 		self.handle.take().unwrap().join().unwrap();
+
 	}
 }
+
+fn die(msg: String) -> ! {
+	println!("ERROR: {}", msg);
+	std::process::exit(1);
+}