forked from coredns/coredns
/
federation.go
96 lines (83 loc) · 2.62 KB
/
federation.go
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package kubernetes
import (
"net"
"strings"
"github.com/coredns/coredns/middleware/etcd/msg"
)
// Federation holds TODO(...).
type Federation struct {
name string
zone string
}
const (
// TODO: Do not hardcode these labels. Pull them out of the API instead.
//
// We can get them via ....
// import metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
// metav1.LabelZoneFailureDomain
// metav1.LabelZoneRegion
//
// But importing above breaks coredns with flag collision of 'log_dir'
labelAvailabilityZone = "failure-domain.beta.kubernetes.io/zone"
labelRegion = "failure-domain.beta.kubernetes.io/region"
)
// stripFederation removes the federation segment from the segment list, if it
// matches a configured federation name.
func (k *Kubernetes) stripFederation(segs []string) (string, []string) {
if len(segs) < 3 {
return "", segs
}
for _, f := range k.Federations {
if f.name == segs[len(segs)-2] {
fed := segs[len(segs)-2]
segs[len(segs)-2] = segs[len(segs)-1]
segs = segs[:len(segs)-1]
return fed, segs
}
}
return "", segs
}
// federationCNAMERecord returns a service record for the requested federated service
// with the target host in the federated CNAME format which the external DNS provider
// should be able to resolve
func (k *Kubernetes) federationCNAMERecord(r recordRequest) msg.Service {
myNodeName := k.localNodeName()
node, err := k.APIConn.GetNodeByName(myNodeName)
if err != nil {
return msg.Service{}
}
for _, f := range k.Federations {
if f.name != r.federation {
continue
}
if r.endpoint == "" {
return msg.Service{
Key: strings.Join([]string{msg.Path(r.zone, "coredns"), r.typeName, r.federation, r.namespace, r.service}, "/"),
Host: strings.Join([]string{r.service, r.namespace, r.federation, r.typeName, node.Labels[labelAvailabilityZone], node.Labels[labelRegion], f.zone}, "."),
}
}
return msg.Service{
Key: strings.Join([]string{msg.Path(r.zone, "coredns"), r.typeName, r.federation, r.namespace, r.service, r.endpoint}, "/"),
Host: strings.Join([]string{r.endpoint, r.service, r.namespace, r.federation, r.typeName, node.Labels[labelAvailabilityZone], node.Labels[labelRegion], f.zone}, "."),
}
}
return msg.Service{}
}
func (k *Kubernetes) localNodeName() string {
localIP := k.interfaceAddrsFunc()
if localIP == nil {
return ""
}
// Find endpoint matching localIP
endpointsList := k.APIConn.EndpointsList()
for _, ep := range endpointsList.Items {
for _, eps := range ep.Subsets {
for _, addr := range eps.Addresses {
if localIP.Equal(net.ParseIP(addr.IP)) {
return *addr.NodeName
}
}
}
}
return ""
}