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Merge pull request #91 from bketelsen/master
Add support for polling a Kubernetes Master server
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,181 @@ | ||
| package main | ||
|
|
||
| import ( | ||
| "flag" | ||
| "log" | ||
| "net" | ||
| "sync" | ||
| "time" | ||
|
|
||
| "encoding/json" | ||
|
|
||
| "github.com/GoogleCloudPlatform/kubernetes/pkg/api" | ||
| "github.com/GoogleCloudPlatform/kubernetes/pkg/client" | ||
| pconfig "github.com/GoogleCloudPlatform/kubernetes/pkg/proxy/config" | ||
| "github.com/GoogleCloudPlatform/kubernetes/pkg/util" | ||
| "github.com/coreos/go-etcd/etcd" | ||
| "github.com/skynetservices/skydns/msg" | ||
| ) | ||
|
|
||
| // The periodic interval for checking the state of things. | ||
| const syncInterval = 5 * time.Second | ||
|
|
||
| type KubernetesSync struct { | ||
| mu sync.Mutex // protects serviceMap | ||
| serviceMap map[string]*serviceInfo | ||
| eclient *etcd.Client | ||
| } | ||
|
|
||
| func NewKubernetesSync(client *etcd.Client) *KubernetesSync { | ||
| ks := &KubernetesSync{ | ||
| serviceMap: make(map[string]*serviceInfo), | ||
| eclient: client, | ||
| } | ||
| return ks | ||
| } | ||
|
|
||
| // This is a belt-and-suspenders loop that periodically | ||
| // addes the records in the local cache of Kubernetes | ||
| // services to the skydns repository to prevent them | ||
| // from expiring. | ||
| func (ksync *KubernetesSync) SyncLoop() { | ||
| for { | ||
| select { | ||
| case <-time.After(syncInterval): | ||
| log.Println("Periodic sync") | ||
| ksync.ensureDNS() | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // Ensure that dns records exist for all services. | ||
| // This seems a bit redundant. TBD - remove? | ||
| func (ksync *KubernetesSync) ensureDNS() { | ||
| ksync.mu.Lock() | ||
| defer ksync.mu.Unlock() | ||
| for name, info := range ksync.serviceMap { | ||
| err := ksync.addDNS(name, info) | ||
| if err != nil { | ||
| log.Println("Failed to ensure dns for %q: %s", name, err) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // OnUpdate manages the active set of service records. | ||
| // Active service records get ttl bumps if found in the update set or | ||
| // removed if missing from the update set. | ||
| func (ksync *KubernetesSync) OnUpdate(services []api.Service) { | ||
| activeServices := util.StringSet{} | ||
| for _, service := range services { | ||
| activeServices.Insert(service.ID) | ||
| info, exists := ksync.getServiceInfo(service.ID) | ||
| serviceIP := net.ParseIP(service.PortalIP) | ||
| if exists && (info.portalPort != service.Port || !info.portalIP.Equal(serviceIP)) { | ||
| err := ksync.removeDNS(service.ID, info) | ||
| if err != nil { | ||
| log.Printf("Failed to remove dns for %q: %s\n", service.ID, err) | ||
| } | ||
| } | ||
| log.Printf("Adding new service %q at %s:%d/%s (local :%d)\n", service.ID, serviceIP, service.Port, service.Protocol, service.ProxyPort) | ||
| si := &serviceInfo{ | ||
| proxyPort: service.ProxyPort, | ||
| protocol: service.Protocol, | ||
| active: true, | ||
| } | ||
| ksync.setServiceInfo(service.ID, si) | ||
| si.portalIP = serviceIP | ||
| si.portalPort = service.Port | ||
| err := ksync.addDNS(service.ID, si) | ||
| if err != nil { | ||
| log.Println("Failed to add dns %q: %s", service.ID, err) | ||
| } | ||
| } | ||
| ksync.mu.Lock() | ||
| defer ksync.mu.Unlock() | ||
| for name, info := range ksync.serviceMap { | ||
| if !activeServices.Has(name) { | ||
| err := ksync.removeDNS(name, info) | ||
| if err != nil { | ||
| log.Println("Failed to remove dns for %q: %s", name, err) | ||
| } | ||
| delete(ksync.serviceMap, name) | ||
| } | ||
| } | ||
| } | ||
|
|
||
| func (ksync *KubernetesSync) getServiceInfo(service string) (*serviceInfo, bool) { | ||
| ksync.mu.Lock() | ||
| defer ksync.mu.Unlock() | ||
| info, ok := ksync.serviceMap[service] | ||
| return info, ok | ||
| } | ||
|
|
||
| func (ksync *KubernetesSync) setServiceInfo(service string, info *serviceInfo) { | ||
| ksync.mu.Lock() | ||
| defer ksync.mu.Unlock() | ||
| ksync.serviceMap[service] = info | ||
| } | ||
|
|
||
| func (ksync *KubernetesSync) removeDNS(service string, info *serviceInfo) error { | ||
| record := service + "." + config.Domain | ||
| // Remove from SkyDNS registration | ||
| log.Printf("removing %s from DNS", record) | ||
| _, err := ksync.eclient.Delete(msg.Path(record), true) | ||
| return err | ||
| } | ||
|
|
||
| func (ksync *KubernetesSync) addDNS(service string, info *serviceInfo) error { | ||
| // ADD to SkyDNS registry | ||
| svc := msg.Service{ | ||
| Host: info.portalIP.String(), | ||
| Port: info.portalPort, | ||
| Priority: 10, | ||
| Weight: 10, | ||
| Ttl: 30, | ||
| } | ||
| b, err := json.Marshal(svc) | ||
| record := service + "." + config.Domain | ||
| //Set with no TTL, and hope that kubernetes events are accurate. | ||
| //TODO(BJK) Think this through a little more | ||
|
|
||
| log.Printf("setting dns record: %v\n", record) | ||
| _, err = ksync.eclient.Set(msg.Path(record), string(b), uint64(0)) | ||
| return err | ||
| } | ||
|
|
||
| type serviceInfo struct { | ||
| portalIP net.IP | ||
| portalPort int | ||
| protocol api.Protocol | ||
| proxyPort int | ||
| mu sync.Mutex // protects active | ||
| active bool | ||
| } | ||
|
|
||
| func init() { | ||
| client.BindClientConfigFlags(flag.CommandLine, clientConfig) | ||
| } | ||
|
|
||
| func WatchKubernetes(eclient *etcd.Client) { | ||
| serviceConfig := pconfig.NewServiceConfig() | ||
| endpointsConfig := pconfig.NewEndpointsConfig() | ||
|
|
||
| // define api config source | ||
| if clientConfig.Host != "" { | ||
| log.Println("Using api calls to get Kubernetes config %v", clientConfig.Host) | ||
| client, err := client.New(clientConfig) | ||
| if err != nil { | ||
| log.Fatalf("Kubernetes requested, but received invalid API configuration: %v", err) | ||
| } | ||
| pconfig.NewSourceAPI( | ||
| client, | ||
| 30*time.Second, | ||
| serviceConfig.Channel("api"), | ||
| endpointsConfig.Channel("api"), | ||
| ) | ||
| } | ||
| ks := NewKubernetesSync(eclient) | ||
| // Wire skydns to handle changes to services | ||
| serviceConfig.RegisterHandler(ks) | ||
| ks.SyncLoop() | ||
| } |
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