From 7708abd8fe456820a84ccdfadc03321ed14763af Mon Sep 17 00:00:00 2001
From: wei liu <wei.liu@zilliz.com>
Date: Tue, 18 Nov 2025 15:41:40 +0800
Subject: [PATCH] fix: Prevent deadlock in runComponent when Prepare fails
 (#45609)

issue: #45068
When component.Prepare() fails (e.g., net listener creation error), the
sign channel was never closed, causing runComponent to block
indefinitely at <-sign. This resulted in the entire process hanging
after logging the error message.

Changes:
- Move close(sign) to defer statement in runComponent goroutine
- Ensures sign channel is always closed regardless of success/failure
- Allows proper error propagation through future.Await() mechanism

---------

Signed-off-by: Wei Liu <wei.liu@zilliz.com>
---
 cmd/roles/roles.go | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/cmd/roles/roles.go b/cmd/roles/roles.go
index b288e9e36a..277fc46770 100644
--- a/cmd/roles/roles.go
+++ b/cmd/roles/roles.go
@@ -114,18 +114,29 @@ func runComponent[T component](ctx context.Context,
 ) *conc.Future[component] {
 	sign := make(chan struct{})
 	future := conc.Go(func() (component, error) {
-		factory := dependency.NewFactory(localMsg)
-		var err error
-		role, err := creator(ctx, factory)
+		// Wrap the creation and preparation phase to enable concurrent component startup
+		prepareFunc := func() (component, error) {
+			defer close(sign)
+			factory := dependency.NewFactory(localMsg)
+			var err error
+			role, err := creator(ctx, factory)
+			if err != nil {
+				return nil, errors.Wrap(err, "create component failed")
+			}
+			if err := role.Prepare(); err != nil {
+				return nil, errors.Wrap(err, "prepare component failed")
+			}
+			healthz.Register(role)
+			metricRegister(Registry.GoRegistry)
+			return role, nil
+		}
+
+		role, err := prepareFunc()
 		if err != nil {
-			return nil, errors.Wrap(err, "create component failed")
+			return nil, err
 		}
-		if err := role.Prepare(); err != nil {
-			return nil, errors.Wrap(err, "prepare component failed")
-		}
-		close(sign)
-		healthz.Register(role)
-		metricRegister(Registry.GoRegistry)
+
+		// Run() executes after sign is closed, allowing components to start concurrently
 		if err := role.Run(); err != nil {
 			return nil, errors.Wrap(err, "run component failed")
 		}