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Marcos Nils 61a0bb4db1 Add support for setting alias when creatign instance. (#140)
* Add support for setting alias when creatign instance.

The POST to create a instance now provides an `alias` field which
then can be used to access the instance services through the following
URL:

`http://<alias>-<short_session>-<port>.<tld>`

When creating a session you can now send an `alias`

* Remove unnecessary function

* Add alias support for DNS resolution
2017-05-11 17:39:17 -03:00

117 lines
3.2 KiB
Go

package handlers
import (
"fmt"
"log"
"net"
"regexp"
"strings"
"github.com/miekg/dns"
"github.com/play-with-docker/play-with-docker/services"
)
var dnsFilter = regexp.MustCompile(`^.*pwd([0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}_[0-9]{1,3}(?:-[0-9]{1,5})?)\..*$`)
var aliasFilter = regexp.MustCompile(`^.*pwd(.*?)-(.*?)[\.-].*`)
func DnsRequest(w dns.ResponseWriter, r *dns.Msg) {
if len(r.Question) > 0 && dnsFilter.MatchString(r.Question[0].Name) {
// this is something we know about and we should try to handle
question := r.Question[0].Name
match := dnsFilter.FindStringSubmatch(question)
tldChunks := strings.Split(match[1], "-")
ip := strings.Replace(tldChunks[0], "_", ".", -1)
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.RecursionAvailable = true
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, ip))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
w.WriteMsg(m)
return
} else if len(r.Question) > 0 && aliasFilter.MatchString(r.Question[0].Name) {
// this is something we know about and we should try to handle
question := r.Question[0].Name
match := aliasFilter.FindStringSubmatch(question)
i := services.FindInstanceByAlias(match[2], match[1])
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.RecursionAvailable = true
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, i.IP))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
w.WriteMsg(m)
return
} else {
if len(r.Question) > 0 {
question := r.Question[0].Name
if question == "localhost." {
log.Printf("Not a PWD host. Asked for [localhost.] returning automatically [127.0.0.1]\n")
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.RecursionAvailable = true
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A 127.0.0.1", question))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
w.WriteMsg(m)
return
}
log.Printf("Not a PWD host. Looking up [%s]\n", question)
ips, err := net.LookupIP(question)
if err != nil {
// we have no information about this and we are not a recursive dns server, so we just fail so the client can fallback to the next dns server it has configured
w.Close()
// dns.HandleFailed(w, r)
return
}
log.Printf("Not a PWD host. Looking up [%s] got [%s]\n", question, ips)
m := new(dns.Msg)
m.SetReply(r)
m.Authoritative = true
m.RecursionAvailable = true
for _, ip := range ips {
ipv4 := ip.To4()
if ipv4 == nil {
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN AAAA %s", question, ip.String()))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
} else {
a, err := dns.NewRR(fmt.Sprintf("%s 60 IN A %s", question, ipv4.String()))
if err != nil {
log.Fatal(err)
}
m.Answer = append(m.Answer, a)
}
}
w.WriteMsg(m)
return
} else {
log.Printf("Not a PWD host. Got DNS without any question\n")
// we have no information about this and we are not a recursive dns server, so we just fail so the client can fallback to the next dns server it has configured
w.Close()
// dns.HandleFailed(w, r)
return
}
}
}