Input Plugin: Adding TTL field for Ping plugin

plugins/inputs/ping/README.md

@@ -70,6 +70,7 @@ LimitNOFILE=4096
     - packets_transmitted (integer)
     - packets_received (integer)
     - percent_packets_loss (float)
+    - ttl (integer, Not available on Windows)
     - average_response_ms (integer)
     - minimum_response_ms (integer)
     - maximum_response_ms (integer)
@@ -92,5 +93,5 @@ ping,url=example.org result_code=0i,average_response_ms=7i,maximum_response_ms=9
 
 **Linux:**
 ```
-ping,url=example.org average_response_ms=23.066,maximum_response_ms=24.64,minimum_response_ms=22.451,packets_received=5i,packets_transmitted=5i,percent_packet_loss=0,result_code=0i,standard_deviation_ms=0.809 1535747258000000000
+ping,url=example.org average_response_ms=23.066,ttl=63,maximum_response_ms=24.64,minimum_response_ms=22.451,packets_received=5i,packets_transmitted=5i,percent_packet_loss=0,result_code=0i,standard_deviation_ms=0.809 1535747258000000000
 ```

plugins/inputs/ping/ping.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"net"
 	"os/exec"
+	"regexp"
 	"runtime"
 	"strconv"
 	"strings"
@@ -151,7 +152,7 @@ func (p *Ping) pingToURL(u string, acc telegraf.Accumulator) {
 		}
 	}
 
-	trans, rec, min, avg, max, stddev, err := processPingOutput(out)
+	trans, rec, ttl, min, avg, max, stddev, err := processPingOutput(out)
 	if err != nil {
 		// fatal error
 		acc.AddError(fmt.Errorf("%s: %s", err, u))
@@ -164,6 +165,9 @@ func (p *Ping) pingToURL(u string, acc telegraf.Accumulator) {
 	fields["packets_transmitted"] = trans
 	fields["packets_received"] = rec
 	fields["percent_packet_loss"] = loss
+	if ttl >= 0 {
+		fields["ttl"] = ttl
+	}
 	if min >= 0 {
 		fields["minimum_response_ms"] = min
 	}
@@ -253,50 +257,74 @@ func (p *Ping) args(url string, system string) []string {
 //     round-trip min/avg/max/stddev = 34.843/43.508/52.172/8.664 ms
 //
 // It returns (<transmitted packets>, <received packets>, <average response>)
-func processPingOutput(out string) (int, int, float64, float64, float64, float64, error) {
-	var trans, recv int
+func processPingOutput(out string) (int, int, int, float64, float64, float64, float64, error) {
+	var trans, recv, ttl int = 0, 0, -1
 	var min, avg, max, stddev float64 = -1.0, -1.0, -1.0, -1.0
 	// Set this error to nil if we find a 'transmitted' line
 	err := errors.New("Fatal error processing ping output")
 	lines := strings.Split(out, "\n")
 	for _, line := range lines {
-		if strings.Contains(line, "transmitted") &&
+		// Reading only first TTL, ignoring other TTL messages
+		if ttl == -1 && strings.Contains(line, "ttl=") {
+			ttl, err = getTTL(line)
+		} else if strings.Contains(line, "transmitted") &&
 			strings.Contains(line, "received") {
-			stats := strings.Split(line, ", ")
-			// Transmitted packets
-			trans, err = strconv.Atoi(strings.Split(stats[0], " ")[0])
-			if err != nil {
-				return trans, recv, min, avg, max, stddev, err
-			}
-			// Received packets
-			recv, err = strconv.Atoi(strings.Split(stats[1], " ")[0])
+			trans, recv, err = getPacketStats(line, trans, recv)
 			if err != nil {
-				return trans, recv, min, avg, max, stddev, err
+				return trans, recv, ttl, min, avg, max, stddev, err
 			}
 		} else if strings.Contains(line, "min/avg/max") {
-			stats := strings.Split(line, " ")[3]
-			data := strings.Split(stats, "/")
-			min, err = strconv.ParseFloat(data[0], 64)
-			if err != nil {
-				return trans, recv, min, avg, max, stddev, err
-			}
-			avg, err = strconv.ParseFloat(data[1], 64)
-			if err != nil {
-				return trans, recv, min, avg, max, stddev, err
-			}
-			max, err = strconv.ParseFloat(data[2], 64)
+			min, avg, max, stddev, err = checkRoundTripTimeStats(line, min, avg, max, stddev)
 			if err != nil {
-				return trans, recv, min, avg, max, stddev, err
-			}
-			if len(data) == 4 {
-				stddev, err = strconv.ParseFloat(data[3], 64)
-				if err != nil {
-					return trans, recv, min, avg, max, stddev, err
-				}
+				return trans, recv, ttl, min, avg, max, stddev, err
 			}
 		}
 	}
-	return trans, recv, min, avg, max, stddev, err
+	return trans, recv, ttl, min, avg, max, stddev, err
+}
+
+func getPacketStats(line string, trans, recv int) (int, int, error) {
+	stats := strings.Split(line, ", ")
+	// Transmitted packets
+	trans, err := strconv.Atoi(strings.Split(stats[0], " ")[0])
+	if err != nil {
+		return trans, recv, err
+	}
+	// Received packets
+	recv, err = strconv.Atoi(strings.Split(stats[1], " ")[0])
+	return trans, recv, err
+}
+
+func getTTL(line string) (int, error) {
+	ttlLine := regexp.MustCompile(`ttl=(\d+)`)
+	ttlMatch := ttlLine.FindStringSubmatch(line)
+	return strconv.Atoi(ttlMatch[1])
+}
+
+func checkRoundTripTimeStats(line string, min, avg, max,
+	stddev float64) (float64, float64, float64, float64, error) {
+	stats := strings.Split(line, " ")[3]
+	data := strings.Split(stats, "/")
+
+	min, err := strconv.ParseFloat(data[0], 64)
+	if err != nil {
+		return min, avg, max, stddev, err
+	}
+	avg, err = strconv.ParseFloat(data[1], 64)
+	if err != nil {
+		return min, avg, max, stddev, err
+	}
+	max, err = strconv.ParseFloat(data[2], 64)
+	if err != nil {
+		return min, avg, max, stddev, err
+	}
+	if len(data) == 4 {
+		stddev, err = strconv.ParseFloat(data[3], 64)
+		if err != nil {
+			return min, avg, max, stddev, err
+		}
+	}
+	return min, avg, max, stddev, err
 }
 
 func init() {

plugins/inputs/ping/ping_test.go

@@ -61,26 +61,29 @@ ping: -i interval too short: Operation not permitted
 
 // Test that ping command output is processed properly
 func TestProcessPingOutput(t *testing.T) {
-	trans, rec, min, avg, max, stddev, err := processPingOutput(bsdPingOutput)
+	trans, rec, ttl, min, avg, max, stddev, err := processPingOutput(bsdPingOutput)
 	assert.NoError(t, err)
+	assert.Equal(t, 55, ttl, "ttl value is 55")
 	assert.Equal(t, 5, trans, "5 packets were transmitted")
 	assert.Equal(t, 5, rec, "5 packets were transmitted")
 	assert.InDelta(t, 15.087, min, 0.001)
 	assert.InDelta(t, 20.224, avg, 0.001)
 	assert.InDelta(t, 27.263, max, 0.001)
 	assert.InDelta(t, 4.076, stddev, 0.001)
 
-	trans, rec, min, avg, max, stddev, err = processPingOutput(linuxPingOutput)
+	trans, rec, ttl, min, avg, max, stddev, err = processPingOutput(linuxPingOutput)
 	assert.NoError(t, err)
+	assert.Equal(t, 63, ttl, "ttl value is 63")
 	assert.Equal(t, 5, trans, "5 packets were transmitted")
 	assert.Equal(t, 5, rec, "5 packets were transmitted")
 	assert.InDelta(t, 35.225, min, 0.001)
 	assert.InDelta(t, 43.628, avg, 0.001)
 	assert.InDelta(t, 51.806, max, 0.001)
 	assert.InDelta(t, 5.325, stddev, 0.001)
 
-	trans, rec, min, avg, max, stddev, err = processPingOutput(busyBoxPingOutput)
+	trans, rec, ttl, min, avg, max, stddev, err = processPingOutput(busyBoxPingOutput)
 	assert.NoError(t, err)
+	assert.Equal(t, 56, ttl, "ttl value is 56")
 	assert.Equal(t, 4, trans, "4 packets were transmitted")
 	assert.Equal(t, 4, rec, "4 packets were transmitted")
 	assert.InDelta(t, 15.810, min, 0.001)
@@ -89,10 +92,37 @@ func TestProcessPingOutput(t *testing.T) {
 	assert.InDelta(t, -1.0, stddev, 0.001)
 }
 
+// Linux ping output with varying TTL
+var linuxPingOutputWithVaryingTTL = `
+PING www.google.com (216.58.218.164) 56(84) bytes of data.
+64 bytes from host.net (216.58.218.164): icmp_seq=1 ttl=63 time=35.2 ms
+64 bytes from host.net (216.58.218.164): icmp_seq=2 ttl=255 time=42.3 ms
+64 bytes from host.net (216.58.218.164): icmp_seq=3 ttl=64 time=45.1 ms
+64 bytes from host.net (216.58.218.164): icmp_seq=4 ttl=64 time=43.5 ms
+64 bytes from host.net (216.58.218.164): icmp_seq=5 ttl=255 time=51.8 ms
+
+--- www.google.com ping statistics ---
+5 packets transmitted, 5 received, 0% packet loss, time 4010ms
+rtt min/avg/max/mdev = 35.225/43.628/51.806/5.325 ms
+`
+
+// Test that ping command output is processed properly
+func TestProcessPingOutputWithVaryingTTL(t *testing.T) {
+	trans, rec, ttl, min, avg, max, stddev, err := processPingOutput(linuxPingOutputWithVaryingTTL)
+	assert.NoError(t, err)
+	assert.Equal(t, 63, ttl, "ttl value is 63")
+	assert.Equal(t, 5, trans, "5 packets were transmitted")
+	assert.Equal(t, 5, rec, "5 packets were transmitted")
+	assert.InDelta(t, 35.225, min, 0.001)
+	assert.InDelta(t, 43.628, avg, 0.001)
+	assert.InDelta(t, 51.806, max, 0.001)
+	assert.InDelta(t, 5.325, stddev, 0.001)
+}
+
 // Test that processPingOutput returns an error when 'ping' fails to run, such
 // as when an invalid argument is provided
 func TestErrorProcessPingOutput(t *testing.T) {
-	_, _, _, _, _, _, err := processPingOutput(fatalPingOutput)
+	_, _, _, _, _, _, _, err := processPingOutput(fatalPingOutput)
 	assert.Error(t, err, "Error was expected from processPingOutput")
 }
 
@@ -160,6 +190,7 @@ func TestPingGather(t *testing.T) {
 		"packets_transmitted":   5,
 		"packets_received":      5,
 		"percent_packet_loss":   0.0,
+		"ttl":                   63,
 		"minimum_response_ms":   35.225,
 		"average_response_ms":   43.628,
 		"maximum_response_ms":   51.806,
@@ -201,6 +232,7 @@ func TestLossyPingGather(t *testing.T) {
 		"packets_transmitted":   5,
 		"packets_received":      3,
 		"percent_packet_loss":   40.0,
+		"ttl":                   63,
 		"minimum_response_ms":   35.225,
 		"average_response_ms":   44.033,
 		"maximum_response_ms":   51.806,
@@ -262,6 +294,8 @@ func TestFatalPingGather(t *testing.T) {
 		"Fatal ping should not have packet measurements")
 	assert.False(t, acc.HasMeasurement("percent_packet_loss"),
 		"Fatal ping should not have packet measurements")
+	assert.False(t, acc.HasMeasurement("ttl"),
+		"Fatal ping should not have packet measurements")
 	assert.False(t, acc.HasMeasurement("minimum_response_ms"),
 		"Fatal ping should not have packet measurements")
 	assert.False(t, acc.HasMeasurement("average_response_ms"),