Build backend config using the K8S endpoint resource.

* Potentialy saves a network hop
* Ability to configure LB algothim (given some work to expose an
anotation etc...)
* K8s config Watch is triggered far less often

provider/k8s/client.go

@@ -22,6 +22,7 @@ const (
 type Client interface {
 	GetIngresses(predicate func(Ingress) bool) ([]Ingress, error)
 	GetServices(predicate func(Service) bool) ([]Service, error)
+	GetEndpoints(name, namespace string) (Endpoints, error)
 	WatchAll(stopCh <-chan bool) (chan interface{}, chan error, error)
 }
 
@@ -104,21 +105,26 @@ func (c *clientImpl) WatchServices(stopCh <-chan bool) (chan interface{}, chan e
 	return c.watch(getURL, stopCh)
 }
 
-// WatchEvents returns events in the cluster
-func (c *clientImpl) WatchEvents(stopCh <-chan bool) (chan interface{}, chan error, error) {
-	getURL := c.endpointURL + APIEndpoint + "/events"
-	return c.watch(getURL, stopCh)
+// GetEndpoints returns the named Endpoints
+// Endpoints have the same name as the coresponding service
+func (c *clientImpl) GetEndpoints(name, namespace string) (Endpoints, error) {
+	getURL := c.endpointURL + APIEndpoint + "/namespaces/" + namespace + "/endpoints/" + name
+
+	body, err := c.do(c.request(getURL))
+	if err != nil {
+		return Endpoints{}, fmt.Errorf("failed to create endpoints request: GET %q : %v", getURL, err)
+	}
+
+	var endpoints Endpoints
+	if err := json.Unmarshal(body, &endpoints); err != nil {
+		return Endpoints{}, fmt.Errorf("failed to decode endpoints resources: %v", err)
+	}
+	return endpoints, nil
 }
 
-// WatchPods returns pods in the cluster
-func (c *clientImpl) WatchPods(stopCh <-chan bool) (chan interface{}, chan error, error) {
-	getURL := c.endpointURL + APIEndpoint + "/pods"
-	return c.watch(getURL, stopCh)
-}
-
-// WatchReplicationControllers returns ReplicationControllers in the cluster
-func (c *clientImpl) WatchReplicationControllers(stopCh <-chan bool) (chan interface{}, chan error, error) {
-	getURL := c.endpointURL + APIEndpoint + "/replicationcontrollers"
+// WatchEndpoints returns endpoints in the cluster
+func (c *clientImpl) WatchEndpoints(stopCh <-chan bool) (chan interface{}, chan error, error) {
+	getURL := c.endpointURL + APIEndpoint + "/endpoints"
 	return c.watch(getURL, stopCh)
 }
 
@@ -137,13 +143,8 @@ func (c *clientImpl) WatchAll(stopCh <-chan bool) (chan interface{}, chan error,
 	if err != nil {
 		return watchCh, errCh, fmt.Errorf("failed to create watch: %v", err)
 	}
-	stopPods := make(chan bool)
-	chanPods, chanPodsErr, err := c.WatchPods(stopPods)
-	if err != nil {
-		return watchCh, errCh, fmt.Errorf("failed to create watch: %v", err)
-	}
-	stopReplicationControllers := make(chan bool)
-	chanReplicationControllers, chanReplicationControllersErr, err := c.WatchReplicationControllers(stopReplicationControllers)
+	stopEndpoints := make(chan bool)
+	chanEndpoints, chanEndpointsErr, err := c.WatchEndpoints(stopEndpoints)
 	if err != nil {
 		return watchCh, errCh, fmt.Errorf("failed to create watch: %v", err)
 	}
@@ -152,32 +153,26 @@ func (c *clientImpl) WatchAll(stopCh <-chan bool) (chan interface{}, chan error,
 		defer close(errCh)
 		defer close(stopIngresses)
 		defer close(stopServices)
-		defer close(stopPods)
-		defer close(stopReplicationControllers)
+		defer close(stopEndpoints)
 
 		for {
 			select {
 			case <-stopCh:
 				stopIngresses <- true
 				stopServices <- true
-				stopPods <- true
-				stopReplicationControllers <- true
+				stopEndpoints <- true
 				return
 			case err := <-chanIngressesErr:
 				errCh <- err
 			case err := <-chanServicesErr:
 				errCh <- err
-			case err := <-chanPodsErr:
-				errCh <- err
-			case err := <-chanReplicationControllersErr:
+			case err := <-chanEndpointsErr:
 				errCh <- err
 			case event := <-chanIngresses:
 				watchCh <- event
 			case event := <-chanServices:
 				watchCh <- event
-			case event := <-chanPods:
-				watchCh <- event
-			case event := <-chanReplicationControllers:
+			case event := <-chanEndpoints:
 				watchCh <- event
 			}
 		}

provider/k8s/endpoints.go

@@ -0,0 +1,84 @@
+package k8s
+
+// Endpoints is a collection of endpoints that implement the actual service.  Example:
+//   Name: "mysvc",
+//   Subsets: [
+//     {
+//       Addresses: [{"ip": "10.10.1.1"}, {"ip": "10.10.2.2"}],
+//       Ports: [{"name": "a", "port": 8675}, {"name": "b", "port": 309}]
+//     },
+//     {
+//       Addresses: [{"ip": "10.10.3.3"}],
+//       Ports: [{"name": "a", "port": 93}, {"name": "b", "port": 76}]
+//     },
+//  ]
+type Endpoints struct {
+	TypeMeta   `json:",inline"`
+	ObjectMeta `json:"metadata,omitempty"`
+
+	// The set of all endpoints is the union of all subsets.
+	Subsets []EndpointSubset
+}
+
+// EndpointSubset is a group of addresses with a common set of ports.  The
+// expanded set of endpoints is the Cartesian product of Addresses x Ports.
+// For example, given:
+//   {
+//     Addresses: [{"ip": "10.10.1.1"}, {"ip": "10.10.2.2"}],
+//     Ports:     [{"name": "a", "port": 8675}, {"name": "b", "port": 309}]
+//   }
+// The resulting set of endpoints can be viewed as:
+//     a: [ 10.10.1.1:8675, 10.10.2.2:8675 ],
+//     b: [ 10.10.1.1:309, 10.10.2.2:309 ]
+type EndpointSubset struct {
+	Addresses         []EndpointAddress
+	NotReadyAddresses []EndpointAddress
+	Ports             []EndpointPort
+}
+
+// EndpointAddress is a tuple that describes single IP address.
+type EndpointAddress struct {
+	// The IP of this endpoint.
+	// IPv6 is also accepted but not fully supported on all platforms. Also, certain
+	// kubernetes components, like kube-proxy, are not IPv6 ready.
+	// TODO: This should allow hostname or IP, see #4447.
+	IP string
+	// Optional: Hostname of this endpoint
+	// Meant to be used by DNS servers etc.
+	Hostname string `json:"hostname,omitempty"`
+	// Optional: The kubernetes object related to the entry point.
+	TargetRef *ObjectReference
+}
+
+// EndpointPort is a tuple that describes a single port.
+type EndpointPort struct {
+	// The name of this port (corresponds to ServicePort.Name).  Optional
+	// if only one port is defined.  Must be a DNS_LABEL.
+	Name string
+
+	// The port number.
+	Port int32
+
+	// The IP protocol for this port.
+	Protocol Protocol
+}
+
+// ObjectReference contains enough information to let you inspect or modify the referred object.
+type ObjectReference struct {
+	Kind            string `json:"kind,omitempty"`
+	Namespace       string `json:"namespace,omitempty"`
+	Name            string `json:"name,omitempty"`
+	UID             UID    `json:"uid,omitempty"`
+	APIVersion      string `json:"apiVersion,omitempty"`
+	ResourceVersion string `json:"resourceVersion,omitempty"`
+
+	// Optional. If referring to a piece of an object instead of an entire object, this string
+	// should contain information to identify the sub-object. For example, if the object
+	// reference is to a container within a pod, this would take on a value like:
+	// "spec.containers{name}" (where "name" refers to the name of the container that triggered
+	// the event) or if no container name is specified "spec.containers[2]" (container with
+	// index 2 in this pod). This syntax is chosen only to have some well-defined way of
+	// referencing a part of an object.
+	// TODO: this design is not final and this field is subject to change in the future.
+	FieldPath string `json:"fieldPath,omitempty"`
+}