♻️ refactor

prototypes/quic_demo/src/executable_end_server.rs

@@ -4,6 +4,8 @@ use tokio::net::TcpStream;
 use crate::prelude::*;
 use protocol::PeerId;
 
+/// A partially-filled-out config that structopt can deal with
+/// Try to turn this into a Config as soon as possible.
 #[derive (Debug, StructOpt)]
 struct Opt {
 	#[structopt (long)]
@@ -17,65 +19,98 @@ struct Opt {
 }
 
 pub async fn main (args: &[OsString]) -> anyhow::Result <()> {
-	let opt = Arc::new (Opt::from_iter (args));
+	let opt = Opt::from_iter (args);
+	let conf = opt.into_config ().await?;
 	
-	let relay_cert: Vec <u8> = match opt.cert_url.as_ref () {
-		Some (url) => reqwest::get (url).await?.bytes ().await?.into_iter ().collect (),
-		None => tokio::fs::read ("quic_server.crt").await?,
-	};
-	let relay_addr: SocketAddr = opt.relay_addr.clone ().unwrap_or_else (|| String::from ("127.0.0.1:30380")).parse ()?;
+	let mut end_server = P4EndServer::connect (conf).await?;
 	
-	let id = opt.server_id.clone ().unwrap_or_else (|| "bogus_server".to_string ());
+	end_server.run ().await?;
+	Ok (())
+}
 
-	let endpoint = make_client_endpoint ("0.0.0.0:0".parse ()?, &[&relay_cert])?;
+/// A filled-out config for constructing an end server
+#[derive (Clone)]
+pub struct Config {
+	pub debug_echo: bool,
+	pub id: String,
+	pub relay_addr: SocketAddr,
+	pub relay_cert: Vec <u8>,
+}
 
-	trace! ("Connecting to relay server");
+impl Opt {
+	/// Converts self into a Config that the server can use.
+	/// Performs I/O to load the relay cert from disk or from HTTP.
+	/// Fails if arguments can't be parsed or if I/O fails.
 	
-	let quinn::NewConnection {
-		bi_streams,
-		..
-	} = protocol::p4_connect_to_p3 (&endpoint, &relay_addr, &id).await?;
+	pub async fn into_config (self) -> anyhow::Result <Config> {
+		let id = self.server_id.clone ().unwrap_or_else (|| "bogus_server".to_string ());
 		
-	let mut end_server = P4EndServer {
-		bi_streams,
-		id,
-		relay_addr,
-		relay_cert,
-	};
+		let relay_addr: SocketAddr = self.relay_addr.clone ().unwrap_or_else (|| String::from ("127.0.0.1:30380")).parse ()?;
 		
-	debug! ("Connected to relay server");
-	trace! ("Accepting bi streams from P3");
+		// Do I/O after all parsing is done.
+		// We don't want to waste a network request only to come back and error
+		// out on like "127.oooo.1" not parsing into a relay address.
 		
-	loop {
-		let (relay_send, relay_recv) = end_server.bi_streams.next ().await.ok_or_else (|| anyhow::anyhow! ("Relay server didn't open a bi stream"))??;
+		let relay_cert: Vec <u8> = match self.cert_url.as_ref () {
+			Some (url) => reqwest::get (url).await?.bytes ().await?.into_iter ().collect (),
+			None => tokio::fs::read ("quic_server.crt").await?,
+		};
 		
-		tokio::spawn (handle_bi_stream (Arc::clone (&opt), relay_send, relay_recv));
+		Ok (Config {
+			debug_echo: self.debug_echo,
+			id,
+			relay_addr,
+			relay_cert,
+		})
 	}
 }
 
+/// An end server that is connected to its relay server
 pub struct P4EndServer {
 	bi_streams: quinn::IncomingBiStreams,
-	id: String,
-	relay_addr: SocketAddr,
-	relay_cert: Vec <u8>,
+	conf: Arc <Config>,
 }
 
 impl P4EndServer {
-	pub fn id (&self) -> &str {
-		&self.id
+	/// Tries to connect to a relay server and return an end server.
+	/// Fails if there's a network issue while making the QUIC connection
+	/// to the relay server.
+	
+	pub async fn connect (conf: Config) -> anyhow::Result <Self> {
+		trace! ("P4 end server making its QUIC endpoint");
+		let endpoint = make_client_endpoint ("0.0.0.0:0".parse ()?, &[&conf.relay_cert])?;
+		
+		trace! ("P4 end server connecting to P3 relay server");
+		let quinn::NewConnection {
+			bi_streams,
+			..
+		} = protocol::p4_connect_to_p3 (&endpoint, &conf.relay_addr, &conf.id).await?;
+		
+		debug! ("Connected to relay server");
+		
+		Ok (P4EndServer {
+			bi_streams,
+			conf: Arc::new (conf),
+		})
 	}
 	
-	pub fn relay_addr (&self) -> SocketAddr {
-		self.relay_addr
+	pub fn config (&self) -> &Config {
+		&*self.conf
 	}
 	
-	pub fn relay_cert (&self) -> &[u8] {
-		&self.relay_cert
+	pub async fn run (&mut self) -> anyhow::Result <()> {
+		trace! ("Accepting bi streams from P3");
+		
+		loop {
+			let (relay_send, relay_recv) = self.bi_streams.next ().await.ok_or_else (|| anyhow::anyhow! ("Relay server didn't open a bi stream"))??;
+			
+			tokio::spawn (handle_bi_stream (Arc::clone (&self.conf), relay_send, relay_recv));
+		}
 	}
 }
 
 async fn handle_bi_stream (
-	opt: Arc <Opt>,
+	conf: Arc <Config>,
 	relay_send: quinn::SendStream,
 	mut relay_recv: quinn::RecvStream,
 ) -> anyhow::Result <()>
@@ -84,14 +119,14 @@ async fn handle_bi_stream (
 		protocol::P3ToP4Stream::NewPtthConnection {
 			client_id,
 			..
-		} => handle_new_ptth_connection (opt, relay_send, relay_recv, client_id).await?,
+		} => handle_new_ptth_connection (conf, relay_send, relay_recv, client_id).await?,
 	}
 	
 	Ok (())
 }
 
 async fn handle_new_ptth_connection (
-	opt: Arc <Opt>,
+	conf: Arc <Config>,
 	mut relay_send: quinn::SendStream,
 	mut relay_recv: quinn::RecvStream,
 	_client_id: String,
@@ -108,7 +143,7 @@ async fn handle_new_ptth_connection (
 	
 	debug! ("Started PTTH connection");
 	
-	if opt.debug_echo {
+	if conf.debug_echo {
 		relay_send.write (b"Connected to P4=P5 debug echo server\n").await?;
 		debug! ("Relaying bytes using internal debug echo server (P4=P5)");
 		tokio::io::copy (&mut relay_recv, &mut relay_send).await?;