From d532b7f23790205a8904df8e86b4b322f86d53ce Mon Sep 17 00:00:00 2001
From: Hao Duan <duanhao0814@gmail.com>
Date: Wed, 13 May 2020 20:23:08 +0800
Subject: [PATCH] metrics: break loop as soon as flags have been set

---
 metrics/metrics.go | 32 ++++++++++++++++++++++++--------
 1 file changed, 24 insertions(+), 8 deletions(-)

diff --git a/metrics/metrics.go b/metrics/metrics.go
index 747d6471a7..2aa96516aa 100644
--- a/metrics/metrics.go
+++ b/metrics/metrics.go
@@ -39,18 +39,34 @@ func init() {
 	for _, arg := range os.Args {
 		flag := strings.TrimLeft(arg, "-")
 
-		for _, enabler := range enablerFlags {
-			if !Enabled && flag == enabler {
-				log.Info("Enabling metrics collection")
-				Enabled = true
+		if !Enabled {
+			// only compare enablerFlags when Enable is not set.
+			for _, enabler := range enablerFlags {
+				if flag == enabler {
+					log.Info("Enabling metrics collection")
+					Enabled = true
+					// break loop if Enabled flag is already set.
+					break
+				}
 			}
 		}
-		for _, enabler := range expensiveEnablerFlags {
-			if !EnabledExpensive && flag == enabler {
-				log.Info("Enabling expensive metrics collection")
-				EnabledExpensive = true
+
+		if !EnabledExpensive {
+			// only compare expensiveEnablerFlags when EnabledExpensive is not set.
+			for _, enabler := range expensiveEnablerFlags {
+				if flag == enabler {
+					log.Info("Enabling expensive metrics collection")
+					EnabledExpensive = true
+					// break loop if EnabledExpensive flag is already set.
+					break
+				}
 			}
 		}
+
+		// break loop as all flags have been set.
+		if Enabled && EnabledExpensive {
+			break
+		}
 	}
 }