From 6cc182de0827ef71ce69bc2f4ad4e0fb89a54bfa Mon Sep 17 00:00:00 2001
From: James Elliott <james-d-elliott@users.noreply.github.com>
Date: Sun, 4 Sep 2022 22:26:03 +1000
Subject: [PATCH] fix(commands): potential nil ptr error on shutdown (#3947)

---
 internal/commands/root.go | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/internal/commands/root.go b/internal/commands/root.go
index 45a262cb5..c532d562e 100644
--- a/internal/commands/root.go
+++ b/internal/commands/root.go
@@ -86,6 +86,7 @@ func cmdRootRun(_ *cobra.Command, _ []string) {
 	runServers(config, providers, logger)
 }
 
+//nolint:gocyclo // Complexity is required in this function.
 func runServers(config *schema.Configuration, providers middlewares.Providers, log *logrus.Logger) {
 	ctx := context.Background()
 
@@ -108,8 +109,8 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 
 	g.Go(func() (err error) {
 		defer func() {
-			if rec := recover(); rec != nil {
-				log.WithError(recoverErr(rec)).Errorf("Critical error in server caught (recovered)")
+			if r := recover(); r != nil {
+				log.WithError(recoverErr(r)).Errorf("Critical error in server caught (recovered)")
 			}
 		}()
 
@@ -118,6 +119,8 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 		}
 
 		if err = mainServer.Serve(mainListener); err != nil {
+			log.WithError(err).Error("Server (main) returned error")
+
 			return err
 		}
 
@@ -130,8 +133,8 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 		}
 
 		defer func() {
-			if rec := recover(); rec != nil {
-				log.WithError(recoverErr(rec)).Errorf("Critical error in metrics server caught (recovered)")
+			if r := recover(); r != nil {
+				log.WithError(recoverErr(r)).Errorf("Critical error in metrics server caught (recovered)")
 			}
 		}()
 
@@ -140,6 +143,8 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 		}
 
 		if err = metricsServer.Serve(metricsListener); err != nil {
+			log.WithError(err).Error("Server (metrics) returned error")
+
 			return err
 		}
 
@@ -147,10 +152,15 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 	})
 
 	select {
-	case <-quit:
-		break
+	case s := <-quit:
+		switch s {
+		case syscall.SIGINT:
+			log.Debugf("Shutdown started due to SIGINT")
+		case syscall.SIGQUIT:
+			log.Debugf("Shutdown started due to SIGQUIT")
+		}
 	case <-ctx.Done():
-		break
+		log.Debugf("Shutdown started due to context completion")
 	}
 
 	cancel()
@@ -159,8 +169,10 @@ func runServers(config *schema.Configuration, providers middlewares.Providers, l
 
 	var err error
 
-	if err = mainServer.Shutdown(); err != nil {
-		log.WithError(err).Errorf("Error occurred shutting down the server")
+	if mainServer != nil {
+		if err = mainServer.Shutdown(); err != nil {
+			log.WithError(err).Errorf("Error occurred shutting down the server")
+		}
 	}
 
 	if metricsServer != nil {