Fix ntpq parse issue when using dns_lookup (#3026)

plugins/inputs/ntpq/ntpq.go

@@ -7,6 +7,7 @@ import (
 	"bytes"
 	"fmt"
 	"os/exec"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -67,6 +68,14 @@ func (n *NTPQ) Gather(acc telegraf.Accumulator) error {
 		return err
 	}
 
+	// Due to problems with a parsing, we have to use regexp expression in order
+	// to remove string that starts from '(' and ends with space
+	// see: https://github.com/influxdata/telegraf/issues/2386
+	reg, err := regexp.Compile("\\([\\S]*")
+	if err != nil {
+		return err
+	}
+
 	lineCounter := 0
 	scanner := bufio.NewScanner(bytes.NewReader(out))
 	for scanner.Scan() {
@@ -80,6 +89,8 @@ func (n *NTPQ) Gather(acc telegraf.Accumulator) error {
 			line = strings.TrimLeft(line, "*#o+x.-")
 		}
 
+		line = reg.ReplaceAllString(line, "")
+
 		fields := strings.Fields(line)
 		if len(fields) < 2 {
 			continue

plugins/inputs/ntpq/ntpq_test.go

@@ -247,6 +247,21 @@ func TestBadWhenNTPQ(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "ntpq", fields, tags)
 }
 
+// TestParserNTPQ - realated to:
+// https://github.com/influxdata/telegraf/issues/2386
+func TestParserNTPQ(t *testing.T) {
+	tt := tester{
+		ret: []byte(multiParserNTPQ),
+		err: nil,
+	}
+
+	n := &NTPQ{
+		runQ: tt.runqTest,
+	}
+	acc := testutil.Accumulator{}
+	assert.NoError(t, acc.GatherError(n.Gather))
+}
+
 func TestMultiNTPQ(t *testing.T) {
 	tt := tester{
 		ret: []byte(multiNTPQ),
@@ -463,3 +478,9 @@ var multiNTPQ = `     remote           refid      st t when poll reach   delay
  5.9.29.107      10.177.80.37     2 u  703 1024  377  205.704  160.406 449602.
  91.189.94.4     10.177.80.37     2 u  673 1024  377  143.047  274.726 449445.
 `
+var multiParserNTPQ = `     remote           refid      st t when poll reach   delay   offset  jitter
+==============================================================================
++37.58.57.238 (d 192.53.103.103			2 u   10 1024  377    1.748    0.373   0.101
++37.58.57.238 (domain) 192.53.103.103   2 u   10 1024  377    1.748    0.373   0.101
++37.58.57.238 ( 192.53.103.103			2 u   10 1024  377    1.748    0.373   0.101
+`