coredns/plugin/kubernetes/external.go
Chris O'Haver 338d148c78 plugin/k8s_external/kubernetes: handle NS records (#3160)
* fix external ns records

* use k8s service name for ns record

* update test, add func comment

* expand nsAddrs() test cases

* support local ipv6 ip

* use less confusing pod ip in test
2019-08-23 16:54:06 +00:00

94 lines
2.6 KiB
Go

package kubernetes
import (
"strings"
"github.com/coredns/coredns/plugin/etcd/msg"
"github.com/coredns/coredns/plugin/kubernetes/object"
"github.com/coredns/coredns/plugin/pkg/dnsutil"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
// External implements the ExternalFunc call from the external plugin.
// It returns any services matching in the services' ExternalIPs.
func (k *Kubernetes) External(state request.Request) ([]msg.Service, int) {
base, _ := dnsutil.TrimZone(state.Name(), state.Zone)
segs := dns.SplitDomainName(base)
last := len(segs) - 1
if last < 0 {
return nil, dns.RcodeServerFailure
}
// We are dealing with a fairly normal domain name here, but we still need to have the service
// and the namespace:
// service.namespace.<base>
//
// for service (and SRV) you can also say _tcp, and port (i.e. _http), we need those be picked
// up, unless they are not specified, then we use an internal wildcard.
port := "*"
protocol := "*"
namespace := segs[last]
if !k.namespaceExposed(namespace) {
return nil, dns.RcodeNameError
}
last--
if last < 0 {
return nil, dns.RcodeSuccess
}
service := segs[last]
last--
if last == 1 {
protocol = stripUnderscore(segs[last])
port = stripUnderscore(segs[last-1])
last -= 2
}
if last != -1 {
// too long
return nil, dns.RcodeNameError
}
idx := object.ServiceKey(service, namespace)
serviceList := k.APIConn.SvcIndex(idx)
services := []msg.Service{}
zonePath := msg.Path(state.Zone, coredns)
rcode := dns.RcodeNameError
for _, svc := range serviceList {
if namespace != svc.Namespace {
continue
}
if service != svc.Name {
continue
}
for _, ip := range svc.ExternalIPs {
for _, p := range svc.Ports {
if !(match(port, p.Name) && match(protocol, string(p.Protocol))) {
continue
}
rcode = dns.RcodeSuccess
s := msg.Service{Host: ip, Port: int(p.Port), TTL: k.ttl}
s.Key = strings.Join([]string{zonePath, svc.Namespace, svc.Name}, "/")
services = append(services, s)
}
}
}
return services, rcode
}
// ExternalAddress returns the external service address(es) for the CoreDNS service.
func (k *Kubernetes) ExternalAddress(state request.Request) []dns.RR {
// If CoreDNS is running inside the Kubernetes cluster: k.nsAddrs() will return the external IPs of the services
// targeting the CoreDNS Pod.
// If CoreDNS is running outside of the Kubernetes cluster: k.nsAddrs() will return the first non-loopback IP
// address seen on the local system it is running on. This could be the wrong answer if coredns is using the *bind*
// plugin to bind to a different IP address.
return k.nsAddrs(true, state.Zone)
}