fix(inputs.ping): honor timeout parameter for native method

Author: wanzh

plugins/inputs/ping/ping.go

@@ -160,10 +160,7 @@ func (p *Ping) nativePing(destination string) (*pingStats, error) {
 
 	pinger.Source = p.sourceAddress
 	pinger.Interval = p.calcInterval
-
-	if p.Deadline > 0 {
-		pinger.Timeout = time.Duration(p.Deadline) * time.Second
-	}
+	pinger.Timeout = p.nativeRunTimeout()
 
 	// Get Time to live (TTL) of first response, matching original implementation
 	once := &sync.Once{}
@@ -191,6 +188,24 @@ func (p *Ping) nativePing(destination string) (*pingStats, error) {
 	return ps, nil
 }
 
+func (p *Ping) nativeRunTimeout() time.Duration {
+	timeout := p.calcTimeout
+	if p.Count > 1 {
+		// With native ping, timeout is global. Approximate per-ping timeout
+		// semantics by adding the delay before the final packet is sent.
+		timeout += p.calcInterval * time.Duration(p.Count-1)
+	}
+
+	if p.Deadline > 0 {
+		deadline := time.Duration(p.Deadline) * time.Second
+		if deadline < timeout {
+			return deadline
+		}
+	}
+
+	return timeout
+}
+
 func (p *Ping) pingToURLNative(destination string, acc telegraf.Accumulator) {
 	tags := map[string]string{"url": destination}
 

plugins/inputs/ping/ping_test.go

@@ -480,6 +480,71 @@ func TestPingGatherNative(t *testing.T) {
 	}
 }
 
+func TestNativeRunTimeout(t *testing.T) {
+	tests := []struct {
+		name         string
+		count        int
+		pingInterval float64
+		timeout      float64
+		deadline     int
+		expected     time.Duration
+	}{
+		{
+			name:         "single packet prefers timeout over larger deadline",
+			count:        1,
+			pingInterval: 1.0,
+			timeout:      1.0,
+			deadline:     10,
+			expected:     time.Second,
+		},
+		{
+			name:         "multiple packets include send interval before final packet",
+			count:        5,
+			pingInterval: 1.0,
+			timeout:      1.0,
+			deadline:     10,
+			expected:     5 * time.Second,
+		},
+		{
+			name:         "no deadline uses timeout based duration",
+			count:        5,
+			pingInterval: 1.0,
+			timeout:      2.0,
+			deadline:     0,
+			expected:     6 * time.Second,
+		},
+		{
+			name:         "deadline caps computed timeout",
+			count:        5,
+			pingInterval: 1.0,
+			timeout:      2.0,
+			deadline:     4,
+			expected:     4 * time.Second,
+		},
+		{
+			name:         "minimum native interval is applied",
+			count:        3,
+			pingInterval: 0.1,
+			timeout:      1.0,
+			deadline:     0,
+			expected:     1400 * time.Millisecond,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			p := &Ping{
+				Count:        tc.count,
+				PingInterval: tc.pingInterval,
+				Timeout:      tc.timeout,
+				Deadline:     tc.deadline,
+			}
+			require.NoError(t, p.Init())
+			require.Equal(t, tc.expected, p.nativeRunTimeout())
+		})
+	}
+}
+
 func TestNoPacketsSent(t *testing.T) {
 	p := &Ping{
 		Log:         testutil.Logger{},