Add kube-peers program

.gitignore

@@ -44,6 +44,7 @@ prog/weavewait/weavewait_noop
 prog/weavewait/weavewait_nomcast
 prog/weaveutil/weaveutil
 prog/*/Dockerfile.weaveworks
+prog/kube-peers/kube-peers
 prog/plugin/plugin
 testing/cover/cover
 testing/runner/runner

.gitmodules

@@ -103,3 +103,6 @@
 [submodule "vendor/github.com/matttproud/golang_protobuf_extensions"]
 	path = vendor/github.com/matttproud/golang_protobuf_extensions
 	url = https://github.com/matttproud/golang_protobuf_extensions
+[submodule "vendor/k8s.io/client-go"]
+	path = vendor/k8s.io/client-go
+	url = https://github.com/kubernetes/client-go

Makefile

@@ -16,6 +16,7 @@ WEAVE_VERSION=git-$(shell git rev-parse --short=12 HEAD)
 WEAVER_EXE=prog/weaver/weaver
 WEAVEPROXY_EXE=prog/weaveproxy/weaveproxy
 SIGPROXY_EXE=prog/sigproxy/sigproxy
+KUBEPEERS_EXE=prog/kube-peers/kube-peers
 WEAVEWAIT_EXE=prog/weavewait/weavewait
 WEAVEWAIT_NOOP_EXE=prog/weavewait/weavewait_noop
 WEAVEWAIT_NOMCAST_EXE=prog/weavewait/weavewait_nomcast
@@ -24,7 +25,7 @@ PLUGIN_EXE=prog/plugin/plugin
 RUNNER_EXE=tools/runner/runner
 TEST_TLS_EXE=test/tls/tls
 
-EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(PLUGIN_EXE) $(TEST_TLS_EXE)
+EXES=$(WEAVER_EXE) $(SIGPROXY_EXE) $(KUBEPEERS_EXE) $(WEAVEPROXY_EXE) $(WEAVEWAIT_EXE) $(WEAVEWAIT_NOOP_EXE) $(WEAVEWAIT_NOMCAST_EXE) $(WEAVEUTIL_EXE) $(PLUGIN_EXE) $(TEST_TLS_EXE)
 
 BUILD_UPTODATE=.build.uptodate
 WEAVER_UPTODATE=.weaver.uptodate
@@ -67,6 +68,7 @@ $(WEAVER_EXE): router/*.go ipam/*.go ipam/*/*.go db/*.go nameserver/*.go prog/we
 $(WEAVEPROXY_EXE): proxy/*.go prog/weaveproxy/*.go
 $(WEAVEUTIL_EXE): prog/weaveutil/*.go net/*.go
 $(SIGPROXY_EXE): prog/sigproxy/*.go
+$(KUBEPEERS_EXE): prog/kube-peers/*.go
 $(PLUGIN_EXE): prog/plugin/*.go plugin/*/*.go api/*.go common/*.go common/docker/*.go net/*.go
 $(TEST_TLS_EXE): test/tls/*.go
 $(WEAVEWAIT_NOOP_EXE): prog/weavewait/*.go
@@ -99,7 +101,7 @@ else
 endif
 	$(NETGO_CHECK)
 
-$(WEAVEUTIL_EXE):
+$(WEAVEUTIL_EXE) $(KUBEPEERS_EXE):
 	go build $(BUILD_FLAGS) -o $@ ./$(@D)
 	$(NETGO_CHECK)
 

prog/kube-peers/main.go

@@ -0,0 +1,55 @@
+package main
+
+import (
+	"fmt"
+	"log"
+
+	"k8s.io/client-go/1.4/kubernetes"
+	"k8s.io/client-go/1.4/pkg/api"
+	"k8s.io/client-go/1.4/rest"
+)
+
+func getKubePeers() ([]string, error) {
+	config, err := rest.InClusterConfig()
+	if err != nil {
+		return nil, err
+	}
+	c, err := kubernetes.NewForConfig(config)
+	if err != nil {
+		return nil, err
+	}
+	nodeList, err := c.Nodes().List(api.ListOptions{})
+	if err != nil {
+		// Fallback for cases (e.g. from kube-up.sh) where kube-proxy is not running on master
+		config.Host = "http://localhost:8080"
+		log.Print("error contacting APIServer: ", err, "; trying with fallback: ", config.Host)
+		c, err = kubernetes.NewForConfig(config)
+		if err != nil {
+			return nil, err
+		}
+		nodeList, err = c.Nodes().List(api.ListOptions{})
+	}
+
+	if err != nil {
+		return nil, err
+	}
+	addresses := make([]string, 0, len(nodeList.Items))
+	for _, peer := range nodeList.Items {
+		for _, addr := range peer.Status.Addresses {
+			if addr.Type == "InternalIP" {
+				addresses = append(addresses, addr.Address)
+			}
+		}
+	}
+	return addresses, nil
+}
+
+func main() {
+	peers, err := getKubePeers()
+	if err != nil {
+		log.Fatalf("Could not get peers: %v", err)
+	}
+	for _, addr := range peers {
+		fmt.Println(addr)
+	}
+}