coredns/plugin/kubernetes/reverse.go
2022-07-10 11:06:33 -07:00

55 lines
1.7 KiB
Go

package kubernetes
import (
"context"
"strings"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/etcd/msg"
"github.com/coredns/coredns/plugin/pkg/dnsutil"
"github.com/coredns/coredns/request"
)
// Reverse implements the ServiceBackend interface.
func (k *Kubernetes) Reverse(ctx context.Context, state request.Request, exact bool, opt plugin.Options) ([]msg.Service, error) {
ip := dnsutil.ExtractAddressFromReverse(state.Name())
if ip == "" {
_, e := k.Records(ctx, state, exact)
return nil, e
}
records := k.serviceRecordForIP(ip, state.Name())
if len(records) == 0 {
return records, errNoItems
}
return records, nil
}
// serviceRecordForIP gets a service record with a cluster ip matching the ip argument
// If a service cluster ip does not match, it checks all endpoints
func (k *Kubernetes) serviceRecordForIP(ip, name string) []msg.Service {
// First check services with cluster ips
for _, service := range k.APIConn.SvcIndexReverse(ip) {
if len(k.Namespaces) > 0 && !k.namespaceExposed(service.Namespace) {
continue
}
domain := strings.Join([]string{service.Name, service.Namespace, Svc, k.primaryZone()}, ".")
return []msg.Service{{Host: domain, TTL: k.ttl}}
}
// If no cluster ips match, search endpoints
var svcs []msg.Service
for _, ep := range k.APIConn.EpIndexReverse(ip) {
if len(k.Namespaces) > 0 && !k.namespaceExposed(ep.Namespace) {
continue
}
for _, eps := range ep.Subsets {
for _, addr := range eps.Addresses {
if addr.IP == ip {
domain := strings.Join([]string{endpointHostname(addr, k.endpointNameMode), ep.Index, Svc, k.primaryZone()}, ".")
svcs = append(svcs, msg.Service{Host: domain, TTL: k.ttl})
}
}
}
}
return svcs
}