From 18374dcbea121060c6c54a2fbededa6bb994aca2 Mon Sep 17 00:00:00 2001
From: Maciej Szulik <maszulik@redhat.com>
Date: Thu, 25 Jun 2020 17:29:32 +0200
Subject: [PATCH] Add the ability to opt-out from config lock file

Kubernetes-commit: 3574d88e22d68fc3291bf1c8432326d0e14fa3bd
---
 tools/clientcmd/config.go | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/tools/clientcmd/config.go b/tools/clientcmd/config.go
index 0babd45f..5f1660bf 100644
--- a/tools/clientcmd/config.go
+++ b/tools/clientcmd/config.go
@@ -58,6 +58,15 @@ type PathOptions struct {
 	LoadingRules *ClientConfigLoadingRules
 }
 
+var (
+	// UseModifyConfigLock ensures that access to kubeconfig file using ModifyConfig method
+	// is being guarded by a lock file.
+	// This variable is intentionaly made public so other consumers of this library
+	// can modify its default behavior, but be caution when disabling it since
+	// this will make your code not threadsafe.
+	UseModifyConfigLock = true
+)
+
 func (o *PathOptions) GetEnvVarFiles() []string {
 	if len(o.EnvVar) == 0 {
 		return []string{}
@@ -156,15 +165,17 @@ func NewDefaultPathOptions() *PathOptions {
 // that means that this code will only write into a single file.  If you want to relativizePaths, you must provide a fully qualified path in any
 // modified element.
 func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, relativizePaths bool) error {
-	possibleSources := configAccess.GetLoadingPrecedence()
-	// sort the possible kubeconfig files so we always "lock" in the same order
-	// to avoid deadlock (note: this can fail w/ symlinks, but... come on).
-	sort.Strings(possibleSources)
-	for _, filename := range possibleSources {
-		if err := lockFile(filename); err != nil {
-			return err
+	if UseModifyConfigLock {
+		possibleSources := configAccess.GetLoadingPrecedence()
+		// sort the possible kubeconfig files so we always "lock" in the same order
+		// to avoid deadlock (note: this can fail w/ symlinks, but... come on).
+		sort.Strings(possibleSources)
+		for _, filename := range possibleSources {
+			if err := lockFile(filename); err != nil {
+				return err
+			}
+			defer unlockFile(filename)
 		}
-		defer unlockFile(filename)
 	}
 
 	startingConfig, err := configAccess.GetStartingConfig()