refactor: revert: "when starting webserver, do not create an extra thread"

src/dfx/src/commands/bootstrap.rs

@@ -68,7 +68,9 @@ pub fn exec(env: &dyn Environment, args: &ArgMatches<'_>) -> DfxResult {
 
     let providers = get_providers(&network_descriptor)?;
 
-    let _ = webserver(
+    let (sender, receiver) = crossbeam::unbounded();
+
+    webserver(
         logger.clone(),
         build_output_root,
         network_descriptor,
@@ -78,7 +80,18 @@ pub fn exec(env: &dyn Environment, args: &ArgMatches<'_>) -> DfxResult {
             .map(|uri| Url::from_str(uri).unwrap())
             .collect(),
         &config_bootstrap.root.unwrap(),
-    )?;
+        sender,
+    )?
+    .join()
+    .map_err(|e| {
+        DfxError::RuntimeError(Error::new(
+            ErrorKind::Other,
+            format!("Failed while running frontend proxy thead -- {:?}", e),
+        ))
+    })?;
+
+    // Wait for the webserver to be started.
+    let _ = receiver.recv().expect("Failed to receive server...");
 
     // Tell the user.
     info!(logger, "Webserver started...");

src/dfx/src/lib/proxy.rs

@@ -90,20 +90,16 @@ impl Proxy {
         providers.push(client_api_uri);
         eprintln!("replica address: {:?}", ic_client_bind_addr);
 
-        let server = run_webserver(
+        run_webserver(
             self.config.logger.clone(),
             self.config.build_output_root.clone(),
             self.config.network_descriptor.clone(),
             self.config.bind,
             providers,
             self.config.serve_dir.clone(),
+            sender.clone(),
         )?;
 
-        // Warning: Note that HttpServer provides its own signal
-        // handler. That means if we provide signal handling beyond basic
-        // we need to either as normal "re-signal" or disable_signals().
-        let _ = sender.send(server);
-
         let mut new_server = Proxy::new(self.config);
         let handle = ServerHandle { sender, receiver };
         new_server.server_handle = ProxyServer::Up(handle);

src/dfx/src/lib/webserver.rs

@@ -10,6 +10,7 @@ use actix_web::client::Client;
 use actix_web::{
     http, middleware, web, App, Error, HttpMessage, HttpRequest, HttpResponse, HttpServer,
 };
+use crossbeam::channel::Sender;
 use futures::StreamExt;
 use serde::Deserialize;
 use slog::{debug, info, trace, Logger};
@@ -171,7 +172,8 @@ pub fn run_webserver(
     bind: SocketAddr,
     providers: Vec<url::Url>,
     serve_dir: PathBuf,
-) -> Result<Server, std::io::Error> {
+    inform_parent: Sender<Server>,
+) -> Result<(), std::io::Error> {
     info!(logger, "binding to: {:?}", bind);
 
     const SHUTDOWN_WAIT_TIME: u64 = 60;
@@ -223,7 +225,12 @@ pub fn run_webserver(
     .system_exit()
     .run();
 
-    Ok(handler)
+    // Warning: Note that HttpServer provides its own signal
+    // handler. That means if we provide signal handling beyond basic
+    // we need to either as normal "re-signal" or disable_signals().
+    let _ = inform_parent.send(handler);
+
+    Ok(())
 }
 
 pub fn webserver(
@@ -233,7 +240,8 @@ pub fn webserver(
     bind: SocketAddr,
     clients_api_uri: Vec<url::Url>,
     serve_dir: &Path,
-) -> DfxResult<Server> {
+    inform_parent: Sender<Server>,
+) -> DfxResult<std::thread::JoinHandle<()>> {
     // Verify that we cannot bind to a port that we forward to.
     let bound_port = bind.port();
     let bind_and_forward_on_same_port = clients_api_uri.iter().any(|url| {
@@ -249,14 +257,22 @@ pub fn webserver(
         ));
     }
 
-    let serve_dir = serve_dir.to_path_buf();
-    run_webserver(
-        logger,
-        build_output_root,
-        network_descriptor,
-        bind,
-        clients_api_uri,
-        serve_dir,
-    )
-    .map_err(DfxError::from)
+    std::thread::Builder::new()
+        .name("Frontend".into())
+        .spawn({
+            let serve_dir = serve_dir.to_path_buf();
+            move || {
+                run_webserver(
+                    logger,
+                    build_output_root,
+                    network_descriptor,
+                    bind,
+                    clients_api_uri,
+                    serve_dir,
+                    inform_parent,
+                )
+                .unwrap()
+            }
+        })
+        .map_err(DfxError::from)
 }