service.go

// Copyright (c) 2014 The SkyDNS Authors. All rights reserved.
// Use of this source code is governed by The MIT License (MIT) that can be
// found in the LICENSE file.

package msg

import (
	"net"
	"path"
	"strings"

	"github.com/miekg/dns"
)

// This *is* the rdata from a SRV record, but with a twist.
// Host (Target in SRV) must be a domain name, but if it looks like an IP
// address (4/6), we will treat it like an IP address.
type Service struct {
	Host     string `json:"host,omitempty"`
	Port     int    `json:"port,omitempty"`
	Priority int    `json:"priority,omitempty"`
	Weight   int    `json:"weight,omitempty"`
	Ttl      uint32 `json:"ttl,omitempty"`
	// etcd key where we found this service and ignore from json un-/marshalling
	Key string `json:"-"`
}

// NewSRV returns a new SRV record based on the Service.
func (s *Service) NewSRV(name string, weight uint16) *dns.SRV {
	return &dns.SRV{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypeSRV, Class: dns.ClassINET, Ttl: s.Ttl},
		Priority: uint16(s.Priority), Weight: weight, Port: uint16(s.Port), Target: dns.Fqdn(s.Host)}
}

// NewA returns a new A record based on the Service.
func (s *Service) NewA(name string, ip net.IP) *dns.A {
	return &dns.A{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: s.Ttl}, A: ip}
}

// NewAAAA returns a new AAAA record based on the Service.
func (s *Service) NewAAAA(name string, ip net.IP) *dns.AAAA {
	return &dns.AAAA{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: s.Ttl}, AAAA: ip}
}

// NewCNAME returns a new CNAME record based on the Service.
func (s *Service) NewCNAME(name string, target string) *dns.CNAME {
	return &dns.CNAME{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypeCNAME, Class: dns.ClassINET, Ttl: s.Ttl}, Target: target}
}

// NewNS returns a new NS record based on the Service.
func (s *Service) NewNS(name string, target string) *dns.NS {
	return &dns.NS{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypeNS, Class: dns.ClassINET, Ttl: s.Ttl}, Ns: target}
}

// NewPTR returns a new PTR record based on the Service.
func (s *Service) NewPTR(name string, ttl uint32) *dns.PTR {
	return &dns.PTR{Hdr: dns.RR_Header{Name: name, Rrtype: dns.TypePTR, Class: dns.ClassINET, Ttl: ttl}, Ptr: dns.Fqdn(s.Host)}
}

// As Path, but
// if a name contains wildcards (*), the name will be chopped of before the (first) wildcard, and
// we do a highler evel search and later find the matching names.
// So service.*.skydns.local, will look for all services under skydns.local and will later check
// for names that match service.*.skydns.local.  If a wildcard is found the returned bool is true.
func PathWithWildcard(s string) (string, bool) {
	l := dns.SplitDomainName(s)
	for i, j := 0, len(l)-1; i < j; i, j = i+1, j-1 {
		l[i], l[j] = l[j], l[i]
	}
	for i, k := range l {
		if k == "*" {
			return path.Join(append([]string{"/skydns/"}, l[:i]...)...), true
		}
	}
	return path.Join(append([]string{"/skydns/"}, l...)...), false
}

// Path converts a domainname to an etcd path. If s looks like service.staging.skydns.local.,
// the resulting key will be /skydns/local/skydns/staging/service .
func Path(s string) string {
	l := dns.SplitDomainName(s)
	for i, j := 0, len(l)-1; i < j; i, j = i+1, j-1 {
		l[i], l[j] = l[j], l[i]
	}
	return path.Join(append([]string{"/skydns/"}, l...)...)
}

// Domain is the opposite of Path.
func Domain(s string) string {
	l := strings.Split(s, "/")
	// start with 1, to strip /skydns
	for i, j := 1, len(l)-1; i < j; i, j = i+1, j-1 {
		l[i], l[j] = l[j], l[i]
	}
	return dns.Fqdn(strings.Join(l[1:len(l)-1], "."))
}