From ebdd9038b727a30904b16fff7503905e53dff67f Mon Sep 17 00:00:00 2001
From: Varsha Teratipally <teratipally@google.com>
Date: Wed, 30 Jun 2021 19:50:16 +0000
Subject: [PATCH] Add a check if the metric is nil so that collector doesn't
 collect the metrics.

---
 pkg/systemstatsmonitor/cpu_collector_linux.go | 100 ++++++++++++------
 1 file changed, 65 insertions(+), 35 deletions(-)

diff --git a/pkg/systemstatsmonitor/cpu_collector_linux.go b/pkg/systemstatsmonitor/cpu_collector_linux.go
index 9e3460bd1..0d10887a6 100644
--- a/pkg/systemstatsmonitor/cpu_collector_linux.go
+++ b/pkg/systemstatsmonitor/cpu_collector_linux.go
@@ -25,7 +25,9 @@ import (
 )
 
 func (cc *cpuCollector) recordLoad() {
-	if cc.mRunnableTaskCount == nil {
+	// don't collect the load metrics if the configs are not present.
+	if cc.mRunnableTaskCount == nil &&
+		cc.mCpuLoad15m == nil && cc.mCpuLoad1m == nil && cc.mCpuLoad5m == nil {
 		return
 	}
 
@@ -35,14 +37,29 @@ func (cc *cpuCollector) recordLoad() {
 		return
 	}
 
-	cc.mRunnableTaskCount.Record(map[string]string{}, loadAvg.Load1)
-
-	cc.mCpuLoad1m.Record(map[string]string{}, loadAvg.Load1)
-	cc.mCpuLoad5m.Record(map[string]string{}, loadAvg.Load5)
-	cc.mCpuLoad15m.Record(map[string]string{}, loadAvg.Load15)
+	if cc.mRunnableTaskCount != nil {
+		cc.mRunnableTaskCount.Record(map[string]string{}, loadAvg.Load1)
+	}
+	if cc.mCpuLoad1m != nil {
+		cc.mCpuLoad1m.Record(map[string]string{}, loadAvg.Load1)
+	}
+	if cc.mCpuLoad5m != nil {
+		cc.mCpuLoad5m.Record(map[string]string{}, loadAvg.Load5)
+	}
+	if cc.mCpuLoad15m != nil {
+		cc.mCpuLoad15m.Record(map[string]string{}, loadAvg.Load15)
+	}
 }
 
 func (cc *cpuCollector) recordSystemStats() {
+
+	// don't collect the load metrics if the configs are not present.
+	if cc.mSystemCPUStat == nil && cc.mSystemInterruptsTotal == nil &&
+		cc.mSystemProcessesTotal == nil && cc.mSystemProcsBlocked == nil &&
+		cc.mSystemProcsRunning == nil {
+		return
+	}
+
 	fs, err := procfs.NewFS("/proc")
 	stats, err := fs.Stat()
 	if err != nil {
@@ -50,34 +67,47 @@ func (cc *cpuCollector) recordSystemStats() {
 		return
 	}
 
-	cc.mSystemProcessesTotal.Record(map[string]string{}, int64(stats.ProcessCreated))
-	cc.mSystemProcsRunning.Record(map[string]string{}, int64(stats.ProcessesRunning))
-	cc.mSystemProcsBlocked.Record(map[string]string{}, int64(stats.ProcessesBlocked))
-	cc.mSystemInterruptsTotal.Record(map[string]string{}, int64(stats.IRQTotal))
-
-	for i, c := range stats.CPU {
-		tags := map[string]string{}
-		tags[cpuLabel] = fmt.Sprintf("cpu%d", i)
-
-		tags[stageLabel] = "user"
-		cc.mSystemCPUStat.Record(tags, c.User)
-		tags[stageLabel] = "nice"
-		cc.mSystemCPUStat.Record(tags, c.Nice)
-		tags[stageLabel] = "system"
-		cc.mSystemCPUStat.Record(tags, c.System)
-		tags[stageLabel] = "idle"
-		cc.mSystemCPUStat.Record(tags, c.Idle)
-		tags[stageLabel] = "iowait"
-		cc.mSystemCPUStat.Record(tags, c.Iowait)
-		tags[stageLabel] = "iRQ"
-		cc.mSystemCPUStat.Record(tags, c.IRQ)
-		tags[stageLabel] = "softIRQ"
-		cc.mSystemCPUStat.Record(tags, c.SoftIRQ)
-		tags[stageLabel] = "steal"
-		cc.mSystemCPUStat.Record(tags, c.Steal)
-		tags[stageLabel] = "guest"
-		cc.mSystemCPUStat.Record(tags, c.Guest)
-		tags[stageLabel] = "guestNice"
-		cc.mSystemCPUStat.Record(tags, c.GuestNice)
+	if cc.mSystemProcessesTotal != nil {
+		cc.mSystemProcessesTotal.Record(map[string]string{}, int64(stats.ProcessCreated))
+	}
+
+	if cc.mSystemProcsRunning != nil {
+		cc.mSystemProcsRunning.Record(map[string]string{}, int64(stats.ProcessesRunning))
+	}
+
+	if cc.mSystemProcsBlocked != nil {
+		cc.mSystemProcsBlocked.Record(map[string]string{}, int64(stats.ProcessesBlocked))
+	}
+
+	if cc.mSystemInterruptsTotal != nil {
+		cc.mSystemInterruptsTotal.Record(map[string]string{}, int64(stats.IRQTotal))
+	}
+
+	if cc.mSystemCPUStat != nil {
+		for i, c := range stats.CPU {
+			tags := map[string]string{}
+			tags[cpuLabel] = fmt.Sprintf("cpu%d", i)
+
+			tags[stageLabel] = "user"
+			cc.mSystemCPUStat.Record(tags, c.User)
+			tags[stageLabel] = "nice"
+			cc.mSystemCPUStat.Record(tags, c.Nice)
+			tags[stageLabel] = "system"
+			cc.mSystemCPUStat.Record(tags, c.System)
+			tags[stageLabel] = "idle"
+			cc.mSystemCPUStat.Record(tags, c.Idle)
+			tags[stageLabel] = "iowait"
+			cc.mSystemCPUStat.Record(tags, c.Iowait)
+			tags[stageLabel] = "iRQ"
+			cc.mSystemCPUStat.Record(tags, c.IRQ)
+			tags[stageLabel] = "softIRQ"
+			cc.mSystemCPUStat.Record(tags, c.SoftIRQ)
+			tags[stageLabel] = "steal"
+			cc.mSystemCPUStat.Record(tags, c.Steal)
+			tags[stageLabel] = "guest"
+			cc.mSystemCPUStat.Record(tags, c.Guest)
+			tags[stageLabel] = "guestNice"
+			cc.mSystemCPUStat.Record(tags, c.GuestNice)
+		}
 	}
 }