Merge pull request #7585 from fasaxc/v3.26-typha-div-0

[v3.26] Fix typha divide by 0

typha/fv-tests/server_test.go

@@ -530,6 +530,37 @@ var _ = Describe("With an in-process Server", func() {
 	})
 })
 
+var _ = Describe("with no client connections", func() {
+	var h *ServerHarness
+
+	BeforeEach(func() {
+		log.SetLevel(log.InfoLevel) // Debug too verbose for tests with a few clients.
+		h = NewHarness()
+	})
+
+	AfterEach(func() {
+		h.Stop()
+	})
+
+	JustBeforeEach(func() {
+		h.Start()
+	})
+
+	Describe("300s shutdown timer and 1s max drop interval", func() {
+		It("should shut drop 1 client per second", func() {
+			Expect(h.Server.NumActiveConnections()).To(Equal(0))
+
+			h.Server.ShutDownGracefully()
+			finishedC := make(chan struct{})
+			go func() {
+				defer close(finishedC)
+				h.Server.Finished.Wait()
+			}()
+			Eventually(finishedC).Should(BeClosed())
+		})
+	})
+})
+
 var _ = Describe("with 5 client connections", func() {
 	const numClients = 5
 

typha/pkg/syncserver/sync_server.go

@@ -572,6 +572,12 @@ func (s *Server) handleGracefulShutDown(cxt context.Context, serverCancelFn cont
 	}
 
 	numConns := s.NumActiveConnections()
+	if numConns == 0 {
+		logCxt.Info("No active connections; shutting down immediately.")
+		serverCancelFn()
+		return
+	}
+
 	// Aim to close connections within 95% of the allotted time.
 	dropInterval := s.config.ShutdownTimeout * 95 / 100 / time.Duration(numConns)
 	logCtx := log.WithFields(log.Fields{
@@ -601,7 +607,7 @@ func (s *Server) handleGracefulShutDown(cxt context.Context, serverCancelFn cont
 				// We don't need to worry about that because serverCancelFn will shut down all remaining connections
 				// by canceling their parent context.
 				serverCancelFn()
-				break
+				return
 			}
 		case <-cxt.Done():
 			logCxt.Info("Context asked us to stop")