Settings: Fix data race when dynamically overriding settings with environment variables (#81667)

Chore: Fix data race when dynamically overriding settings with environment variables

pkg/util/osutil/osutil.go

@@ -0,0 +1,42 @@
+package osutil
+
+import (
+	"os"
+)
+
+// Env collects global functions from standard package "os" that are related to
+// environment variables. This allows abstracting code and provides a way to
+// concurrently test code that needs access to these shared resources.
+type Env interface {
+	Setenv(key, value string) error
+	Getenv(key string) string
+}
+
+// RealEnv implements Env interface by calling the actual global functions in
+// package "os". This should be used by default anywhere that an Env is
+// expected, and use MapEnv instead in your unit tests.
+type RealEnv struct{}
+
+func (RealEnv) Setenv(key, value string) error {
+	return os.Setenv(key, value)
+}
+
+func (RealEnv) Getenv(key string) string {
+	return os.Getenv(key)
+}
+
+// MapEnv is a fake implementing Env interface. It is purposefully not
+// concurrency-safe, so if your tests using it panic due to concurrent map
+// access, then you need to fix a data race in your code. This is
+// because environment variables are globals to a process, so you should be
+// properly synchronizing access to them (e.g. with a mutex).
+type MapEnv map[string]string
+
+func (m MapEnv) Setenv(key, value string) error {
+	m[key] = value
+	return nil
+}
+
+func (m MapEnv) Getenv(key string) string {
+	return m[key]
+}