Query servers in parallel in dns_query input (#4754)

plugins/inputs/dns_query/dns_query.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"net"
 	"strconv"
+	"sync"
 	"time"
 
 	"github.com/miekg/dns"
@@ -70,10 +71,13 @@ func (d *DnsQuery) Description() string {
 	return "Query given DNS server and gives statistics"
 }
 func (d *DnsQuery) Gather(acc telegraf.Accumulator) error {
+	var wg sync.WaitGroup
 	d.setDefaultValues()
 
 	for _, domain := range d.Domains {
 		for _, server := range d.Servers {
+			wg.Add(1)
+			go func(domain, server string) {
 				fields := make(map[string]interface{}, 2)
 				tags := map[string]string{
 					"server":      server,
@@ -93,9 +97,11 @@ func (d *DnsQuery) Gather(acc telegraf.Accumulator) error {
 				}
 
 				acc.AddFields("dns_query", fields, tags)
+			}(domain, server)
 		}
 	}
 
+	wg.Wait()
 	return nil
 }