From d69d318cb0d3ba8ce2d652606fa1192ac9a42b97 Mon Sep 17 00:00:00 2001
From: Dmitrii Stepanov <d.stepanov@yadro.com>
Date: Mon, 18 Dec 2023 17:55:24 +0300
Subject: [PATCH] [#878] node: Drain internal error's channel

This fixes shutdown panic:
1. Some morph connection gets error and passes it to internalErr channel.
2. Storage node starts to shutdow and closes internalErr channel.
3. Other morph connection gets error and tries to pass it to internalErr channel.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
---
 cmd/frostfs-node/config.go |  1 -
 cmd/frostfs-node/main.go   | 14 ++++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/cmd/frostfs-node/config.go b/cmd/frostfs-node/config.go
index 88b93e6a..82e20378 100644
--- a/cmd/frostfs-node/config.go
+++ b/cmd/frostfs-node/config.go
@@ -1328,5 +1328,4 @@ func (c *cfg) shutdown() {
 	for i := range c.closers {
 		c.closers[len(c.closers)-1-i].fn()
 	}
-	close(c.internalErr)
 }
diff --git a/cmd/frostfs-node/main.go b/cmd/frostfs-node/main.go
index 2fe3a0a2..f91a6dec 100644
--- a/cmd/frostfs-node/main.go
+++ b/cmd/frostfs-node/main.go
@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"sync"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-node/config"
 	"git.frostfs.info/TrueCloudLab/frostfs-node/internal/logs"
@@ -155,9 +156,22 @@ func wait(c *cfg) {
 
 	<-c.done // graceful shutdown
 
+	drain := &sync.WaitGroup{}
+	drain.Add(1)
+	go func() {
+		defer drain.Done()
+		for err := range c.internalErr {
+			c.log.Warn(logs.FrostFSNodeInternalApplicationError,
+				zap.String("message", err.Error()))
+		}
+	}()
+
 	c.log.Debug(logs.FrostFSNodeWaitingForAllProcessesToStop)
 
 	c.wg.Wait()
+
+	close(c.internalErr)
+	drain.Wait()
 }
 
 func (c *cfg) onShutdown(f func()) {