add a non_blocking method for start worker

actix-server/src/worker.rs

@@ -193,22 +193,67 @@ impl ServerWorkerConfig {
 }
 
 impl ServerWorker {
+    /// Start server worker in sync.
     pub(crate) fn start(
+        idx: usize,
+        factories: Vec<Box<dyn InternalServiceFactory>>,
+        avail: WorkerAvailability,
+        config: ServerWorkerConfig,
+    ) -> io::Result<(WorkerHandleAccept, WorkerHandleServer)> {
+        let (factory_tx, factory_rx) = std::sync::mpsc::sync_channel(1);
+
+        let (tx1, tx2) = Self::_start(idx, factories, avail.clone(), config, move |err| {
+            factory_tx.send(err).unwrap()
+        })?;
+
+        factory_rx
+            .recv()
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?
+            .map(Err)
+            .unwrap_or_else(|| Ok(handle_pair(idx, tx1, tx2, avail)))
+    }
+
+    #[allow(dead_code)]
+    /// Start server worker in async.
+    pub(crate) fn start_non_blocking(
+        idx: usize,
+        factories: Vec<Box<dyn InternalServiceFactory>>,
+        avail: WorkerAvailability,
+        config: ServerWorkerConfig,
+    ) -> impl Future<Output = io::Result<(WorkerHandleAccept, WorkerHandleServer)>> {
+        let (factory_tx, factory_rx) = oneshot::channel();
+
+        let res = Self::_start(idx, factories, avail.clone(), config, move |err| {
+            factory_tx.send(err).unwrap()
+        });
+
+        async move {
+            let (tx1, tx2) = res?;
+            factory_rx
+                .await
+                .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?
+                .map(Err)
+                .unwrap_or_else(|| Ok(handle_pair(idx, tx1, tx2, avail)))
+        }
+    }
+
+    fn _start<F>(
         idx: usize,
         factories: Vec<Box<dyn InternalServiceFactory>>,
         availability: WorkerAvailability,
         config: ServerWorkerConfig,
-    ) -> io::Result<(WorkerHandleAccept, WorkerHandleServer)> {
+        f: F,
+    ) -> io::Result<(UnboundedSender<Conn>, UnboundedSender<Stop>)>
+    where
+        F: FnOnce(Option<io::Error>) + Send + 'static,
+    {
         assert!(!availability.available());
-        let avail = availability.clone();
-
-        let (tx1, rx) = unbounded_channel();
-        let (tx2, rx2) = unbounded_channel();
 
         // Try to get actix system when have one.
         let system = System::try_current();
 
-        let (factory_tx, factory_rx) = std::sync::mpsc::sync_channel(1);
+        let (tx1, rx) = unbounded_channel();
+        let (tx2, rx2) = unbounded_channel();
 
         // every worker runs in it's own thread.
         thread::Builder::new()
@@ -223,12 +268,12 @@ impl ServerWorker {
 
                 // use a custom tokio runtime builder to change the settings of runtime.
                 let local = tokio::task::LocalSet::new();
-                let res = tokio::runtime::Builder::new_current_thread()
+                let rt = tokio::runtime::Builder::new_current_thread()
                     .enable_all()
                     .max_blocking_threads(config.max_blocking_threads)
-                    .build()
-                    .and_then(|rt| {
-                        local.block_on(&rt, async {
+                    .build();
+                let res = rt.and_then(|rt| {
+                    let fut = async {
                         for (idx, factory) in factories.iter().enumerate() {
                             let service = factory.create().await.map_err(|_| {
                                 io::Error::new(
@@ -247,14 +292,14 @@ impl ServerWorker {
                             }
                         }
                         Ok::<_, io::Error>(())
-                        })?;
+                    };
 
-                        Ok(rt)
+                    local.block_on(&rt, fut).map(|_| rt)
                 });
 
                 match res {
                     Ok(rt) => {
-                        factory_tx.send(None).unwrap();
+                        f(None);
 
                         let worker = ServerWorker {
                             rx,
@@ -269,16 +314,11 @@ impl ServerWorker {
 
                         local.block_on(&rt, async { worker.await });
                     }
-                    Err(e) => factory_tx.send(Some(e)).unwrap(),
+                    Err(e) => f(Some(e)),
                 }
             })
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
-
-        factory_rx
-            .recv()
-            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?
-            .map(Err)
-            .unwrap_or_else(|| Ok(handle_pair(idx, tx1, tx2, avail)))
+            .map(|_| (tx1, tx2))
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
     }
 
     fn restart_service(&mut self, token: Token, factory_id: usize) {