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/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"`
+}