RepoMirrors
/
prometheus
mirror of https://github.com/prometheus/prometheus
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add search domain support to SRV lookups 

This adds search domain support by trying to resolve a name by
appending each search domain configured in /etc/resolv.conf until
the query succeeds (NOERROR) and has at least one answer.

Change-Id: Ibdc5138c5d8cc049e11fab90c3d5243d5a06852c
This commit is contained in:
Johannes 'fish' Ziemke 2013-10-29 16:34:00 +01:00
parent 39417f93ee
commit 8c08a5031f
1 changed files with 28 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
retrieval/target_provider.go
View File

@ -16,6 +16,8 @@ package retrieval
import (
"fmt"
"net/url"
"strconv"
"strings"
"time"
"github.com/golang/glog"
@ -95,19 +97,31 @@ func (p *sdTargetProvider) Targets() ([]Target, error) {
}
func lookupSRV(name string) (*dns.Msg, error) {
name = dns.Fqdn(name)
conf, err := dns.ClientConfigFromFile(resolvConf)
if err != nil {
return nil, fmt.Errorf("Couldn't load resolv.conf: %s", err)
}
client := &dns.Client{}
msg := &dns.Msg{}
msg.SetQuestion(name, dns.TypeSRV)
port, err := strconv.Atoi(conf.Port)
if err != nil {
return nil, fmt.Errorf("Invalid dns port in %s", resolvConf)
}
client := &dns.Client{}
response := &dns.Msg{}
for _, server := range conf.Servers {
server := fmt.Sprintf("%s:%s", server, conf.Port)
response, err = lookup(msg, client, server, false)
for _, suffix := range conf.Search {
response, err = lookup(name, dns.TypeSRV, client, server, port, suffix, false)
if err == nil {
if len(response.Answer) > 0 {
return response, nil
}
} else {
glog.Warningf("Resolving %s.%s failed: %s", name, suffix, err)
}
}
response, err = lookup(name, dns.TypeSRV, client, server, port, "", false)
if err == nil {
return response, nil
}
@ -115,7 +129,12 @@ func lookupSRV(name string) (*dns.Msg, error) {
return response, fmt.Errorf("Couldn't resolve %s: No server responded", name)
}
func lookup(msg *dns.Msg, client *dns.Client, server string, edns bool) (*dns.Msg, error) {
func lookup(name string, queryType uint16, client *dns.Client, server string, port int, suffix string, edns bool) (*dns.Msg, error) {
msg := &dns.Msg{}
lname := strings.Join([]string{name, suffix}, ".")
glog.Warning("Resolving ", dns.Fqdn(lname))
msg.SetQuestion(dns.Fqdn(lname), queryType)
if edns {
opt := &dns.OPT{
Hdr: dns.RR_Header{
@ -127,7 +146,7 @@ func lookup(msg *dns.Msg, client *dns.Client, server string, edns bool) (*dns.Ms
msg.Extra = append(msg.Extra, opt)
}
response, _, err := client.Exchange(msg, server)
response, _, err := client.Exchange(msg, fmt.Sprintf("%s:%d", server, port))
if err != nil {
return nil, err
}
@ -145,7 +164,7 @@ func lookup(msg *dns.Msg, client *dns.Client, server string, edns bool) (*dns.Ms
client.Net = "tcp"
}
return lookup(msg, client, server, !edns)
return lookup(name, queryType, client, server, port, suffix, !edns)
}
return response, nil