Merge pull request #3179 from jen20/nan-floats

client: Guard against "NaN" values from floats

client/stats/host.go

@@ -231,13 +231,27 @@ func (h *HostCpuStatsCalculator) Calculate(times cpu.TimesStat) (idle float64, u
 
 	deltaTotal := currentTotal - h.prevTotal
 	idle = ((currentIdle - h.prevIdle) / deltaTotal) * 100
+	if math.IsNaN(idle) {
+		idle = 100.0
+	}
+
 	user = ((currentUser - h.prevUser) / deltaTotal) * 100
+	if math.IsNaN(user) {
+		user = 0.0
+	}
+
 	system = ((currentSystem - h.prevSystem) / deltaTotal) * 100
+	if math.IsNaN(system) {
+		system = 0.0
+	}
 
 	currentBusy := times.User + times.System + times.Nice + times.Iowait + times.Irq +
 		times.Softirq + times.Steal + times.Guest + times.GuestNice + times.Stolen
 
 	total = ((currentBusy - h.prevBusy) / deltaTotal) * 100
+	if math.IsNaN(total) {
+		total = 0.0
+	}
 
 	h.prevIdle = currentIdle
 	h.prevUser = currentUser

client/stats/host_test.go

@@ -0,0 +1,32 @@
+package stats
+
+import (
+	"testing"
+
+	"github.com/shirou/gopsutil/cpu"
+)
+
+func TestHostCpuStatsCalculator_Nan(t *testing.T) {
+	times := cpu.TimesStat{
+		User:   0.0,
+		Idle:   100.0,
+		System: 0.0,
+	}
+
+	calculator := NewHostCpuStatsCalculator()
+	calculator.Calculate(times)
+	idle, user, system, total := calculator.Calculate(times)
+
+	if idle != 100.0 {
+		t.Errorf("idle: Expected: %f, Got %f", 100.0, idle)
+	}
+	if user != 0.0 {
+		t.Errorf("user: Expected: %f, Got %f", 0.0, user)
+	}
+	if system != 0.0 {
+		t.Errorf("system: Expected: %f, Got %f", 0.0, system)
+	}
+	if total != 0.0 {
+		t.Errorf("total: Expected: %f, Got %f", 0.0, total)
+	}
+}