feat: add ShutdownWithContext (#1383)

server.go

@@ -1829,6 +1829,17 @@ func (s *Server) Serve(ln net.Listener) error {
 //
 // Shutdown does not close keepalive connections so its recommended to set ReadTimeout and IdleTimeout to something else than 0.
 func (s *Server) Shutdown() error {
+	return s.ShutdownWithContext(context.Background())
+}
+
+// ShutdownWithContext gracefully shuts down the server without interrupting any active connections.
+// ShutdownWithContext works by first closing all open listeners and then waiting for all connections to return to idle or context timeout and then shut down.
+//
+// When ShutdownWithContext is called, Serve, ListenAndServe, and ListenAndServeTLS immediately return nil.
+// Make sure the program doesn't exit and waits instead for Shutdown to return.
+//
+// ShutdownWithContext does not close keepalive connections so its recommended to set ReadTimeout and IdleTimeout to something else than 0.
+func (s *Server) ShutdownWithContext(ctx context.Context) (err error) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
@@ -1840,7 +1851,7 @@ func (s *Server) Shutdown() error {
 	}
 
 	for _, ln := range s.ln {
-		if err := ln.Close(); err != nil {
+		if err = ln.Close(); err != nil {
 			return err
 		}
 	}
@@ -1851,7 +1862,10 @@ func (s *Server) Shutdown() error {
 
 	// Closing the listener will make Serve() call Stop on the worker pool.
 	// Setting .stop to 1 will make serveConn() break out of its loop.
-	// Now we just have to wait until all workers are done.
+	// Now we just have to wait until all workers are done or timeout.
+	ticker := time.NewTicker(time.Millisecond * 100)
+	defer ticker.Stop()
+END:
 	for {
 		s.closeIdleConns()
 
@@ -1861,12 +1875,18 @@ func (s *Server) Shutdown() error {
 		// This is not an optimal solution but using a sync.WaitGroup
 		// here causes data races as it's hard to prevent Add() to be called
 		// while Wait() is waiting.
-		time.Sleep(time.Millisecond * 100)
+		select {
+		case <-ctx.Done():
+			err = ctx.Err()
+			break END
+		case <-ticker.C:
+			continue
+		}
 	}
 
 	s.done = nil
 	s.ln = nil
-	return nil
+	return err
 }
 
 func acceptConn(s *Server, ln net.Listener, lastPerIPErrorTime *time.Time) (net.Conn, error) {

server_test.go

@@ -16,6 +16,7 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"testing"
 	"time"
 
@@ -3594,6 +3595,57 @@ func TestShutdownCloseIdleConns(t *testing.T) {
 	}
 }
 
+func TestShutdownWithContext(t *testing.T) {
+	t.Parallel()
+
+	ln := fasthttputil.NewInmemoryListener()
+	s := &Server{
+		Handler: func(ctx *RequestCtx) {
+			time.Sleep(5 * time.Second)
+			ctx.Success("aaa/bbb", []byte("real response"))
+		},
+	}
+	go func() {
+		if err := s.Serve(ln); err != nil {
+			t.Errorf("unexepcted error: %v", err)
+		}
+	}()
+	time.Sleep(1 * time.Second)
+	go func() {
+		conn, err := ln.Dial()
+		if err != nil {
+			t.Errorf("unexepcted error: %v", err)
+		}
+
+		if _, err = conn.Write([]byte("GET / HTTP/1.1\r\nHost: google.com\r\n\r\n")); err != nil {
+			t.Errorf("unexpected error: %v", err)
+		}
+		br := bufio.NewReader(conn)
+		verifyResponse(t, br, StatusOK, "aaa/bbb", "real response")
+	}()
+
+	time.Sleep(1 * time.Second)
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Millisecond)
+	defer cancel()
+	shutdownErr := make(chan error)
+	go func() {
+		shutdownErr <- s.ShutdownWithContext(ctx)
+	}()
+
+	timer := time.NewTimer(time.Second)
+	select {
+	case <-timer.C:
+		t.Fatal("idle connections not closed on shutdown")
+	case err := <-shutdownErr:
+		if err == nil || err != context.DeadlineExceeded {
+			t.Fatalf("unexpected err %v. Expecting %v", err, context.DeadlineExceeded)
+		}
+	}
+	if atomic.LoadInt32(&s.open) != 1 {
+		t.Fatalf("unexpected open connection num: %#v. Expecting %#v", atomic.LoadInt32(&s.open), 1)
+	}
+}
+
 func TestMultipleServe(t *testing.T) {
 	t.Parallel()