add feature to specify default backend

bench/rpxy.toml

@@ -5,6 +5,7 @@ listen_ipv6 = false
 max_concurrent_streams = 128
 max_clients = 512
 
+default_app = 'localhost' # passing through 127.0.0.1
 
 [apps]
 

config-example.toml

@@ -15,6 +15,13 @@ max_clients = 512
 
 listen_ipv6 = false
 
+# App that serves all plaintext http request by referring to HOSTS or request header
+# execpt for configured application.
+# Note that this is only for http.
+# Note that nothing is served for requests via https since secure channel cannot be
+# established for unconfigured server_name, and they are always rejected by checking SNI.
+default_app = 'another_localhost'
+
 ###################################
 #         Backend settings        #
 ###################################

src/backend.rs

@@ -12,6 +12,11 @@ use std::{
 };
 use tokio_rustls::rustls::{Certificate, PrivateKey, ServerConfig};
 
+pub struct Backends {
+  pub apps: HashMap<String, Backend>, // TODO: hyper::uriで抜いたhostで引っ掛ける。Stringでいいのか？
+  pub default_app: Option<String>,    // for plaintext http
+}
+
 pub struct Backend {
   pub app_name: String,
   pub server_name: String,

src/config/parse.rs

@@ -7,7 +7,7 @@ use std::{collections::HashMap, sync::Mutex};
 // #[cfg(feature = "tls")]
 use std::path::PathBuf;
 
-pub fn parse_opts(globals: &mut Globals, backends: &mut HashMap<String, Backend>) -> Result<()> {
+pub fn parse_opts(globals: &mut Globals, backends: &mut Backends) -> Result<()> {
   let _ = include_str!("../../Cargo.toml");
   let options = clap::command!().arg(
     Arg::new("config_file")
@@ -110,7 +110,7 @@ pub fn parse_opts(globals: &mut Globals, backends: &mut HashMap<String, Backend>
     ensure!(app.reverse_proxy.is_some(), "Missing reverse_proxy");
     let reverse_proxy = get_reverse_proxy(app.reverse_proxy.as_ref().unwrap())?;
 
-    backends.insert(
+    backends.apps.insert(
       server_name.to_owned(),
       Backend {
         app_name: app_name.to_owned(),
@@ -125,6 +125,18 @@ pub fn parse_opts(globals: &mut Globals, backends: &mut HashMap<String, Backend>
     );
     info!("Registering application: {} ({})", app_name, server_name);
   }
+
+  // default backend application for plaintext http requests
+  if let Some(d) = config.default_app {
+    if backends.apps.contains_key(&d) {
+      info!(
+        "Serving plaintext http for requests to unconfigured server_name: {}.",
+        d
+      );
+    }
+    backends.default_app = Some(d);
+  }
+
   Ok(())
 }
 

src/config/toml.rs

@@ -10,6 +10,7 @@ pub struct ConfigToml {
   pub max_concurrent_streams: Option<u32>,
   pub max_clients: Option<u32>,
   pub apps: Option<Apps>,
+  pub default_app: Option<String>,
 }
 
 #[derive(Deserialize, Debug, Default)]

src/main.rs

@@ -10,7 +10,13 @@ mod log;
 mod proxy;
 
 use crate::{
-  backend::Backend, config::parse_opts, constants::*, error::*, globals::*, log::*, proxy::Proxy,
+  backend::{Backend, Backends},
+  config::parse_opts,
+  constants::*,
+  error::*,
+  globals::*,
+  log::*,
+  proxy::Proxy,
 };
 use futures::future::select_all;
 use hyper::Client;
@@ -55,7 +61,10 @@ fn main() {
       runtime_handle: runtime.handle().clone(),
     };
 
-    let mut backends: HashMap<String, Backend> = HashMap::new();
+    let mut backends = Backends {
+      default_app: None,
+      apps: HashMap::<String, Backend>::new(),
+    };
 
     let _ = parse_opts(&mut globals, &mut backends).expect("Invalid configuration");
 
@@ -67,7 +76,7 @@ fn main() {
 }
 
 // entrypoint creates and spawns tasks of proxy services
-async fn entrypoint(globals: Arc<Globals>, backends: Arc<HashMap<String, Backend>>) -> Result<()> {
+async fn entrypoint(globals: Arc<Globals>, backends: Arc<Backends>) -> Result<()> {
   let connector = TrustDnsResolver::default().into_rustls_webpki_https_connector();
   let forwarder = Arc::new(Client::builder().build::<_, hyper::Body>(connector));
 

src/proxy/proxy_handler.rs

@@ -39,8 +39,11 @@ where
     } else {
       return http_error(StatusCode::SERVICE_UNAVAILABLE);
     };
-    let backend = if let Some(be) = self.backends.get(server_name.as_str()) {
+    let backend = if let Some(be) = self.backends.apps.get(server_name.as_str()) {
       be
+    } else if let Some(default_be) = &self.backends.default_app {
+      debug!("Serving by default app: {}", default_be);
+      self.backends.apps.get(default_be).unwrap()
     } else {
       return http_error(StatusCode::SERVICE_UNAVAILABLE);
     };

src/proxy/proxy_main.rs

@@ -1,9 +1,9 @@
 // use super::proxy_handler::handle_request;
-use crate::{backend::Backend, error::*, globals::Globals, log::*};
+use crate::{backend::Backends, error::*, globals::Globals, log::*};
 use hyper::{
   client::connect::Connect, server::conn::Http, service::service_fn, Body, Client, Request,
 };
-use std::{collections::HashMap, net::SocketAddr, sync::Arc};
+use std::{net::SocketAddr, sync::Arc};
 use tokio::{
   io::{AsyncRead, AsyncWrite},
   net::TcpListener,
@@ -39,7 +39,7 @@ where
 {
   pub listening_on: SocketAddr,
   pub tls_enabled: bool, // TCP待受がTLSかどうか
-  pub backends: Arc<HashMap<String, Backend>>, // TODO: hyper::uriで抜いたhostで引っ掛ける。Stringでいいのか？
+  pub backends: Arc<Backends>,
   pub forwarder: Arc<Client<T>>,
   pub globals: Arc<Globals>,
 }

src/proxy/proxy_tls.rs

@@ -17,7 +17,7 @@ where
     let cert_service = async {
       info!("Start cert watch service for {}", self.listening_on);
       loop {
-        for (server_name, backend) in self.backends.iter() {
+        for (server_name, backend) in self.backends.apps.iter() {
           if backend.tls_cert_key_path.is_some() && backend.tls_cert_path.is_some() {
             if let Err(_e) = backend.update_server_config().await {
               warn!("Failed to update certs for {}", server_name);
@@ -53,7 +53,7 @@ where
               info!("No SNI in ClientHello");
               continue;
             };
-            let backend_serve = if let Some(backend_serve) = self.backends.get(svn){
+            let backend_serve = if let Some(backend_serve) = self.backends.apps.get(svn){
               backend_serve
             } else {
               info!("No configuration for the server name {} given in client_hello", svn);