Add GET /ipinfo/tracker

The endpoint returns the name of tracker. It is used to determine
whether the router is running a tracker.

api/ipam.go

@@ -53,6 +53,14 @@ func (client *Client) DefaultSubnet() (*net.IPNet, error) {
 	return ipnet, err
 }
 
+func (client *Client) LocalRangeTracker() (string, error) {
+	t, err := client.httpVerb("GET", fmt.Sprintf("/ipinfo/tracker"), nil)
+	if err != nil {
+		return "", err
+	}
+	return t, nil
+}
+
 func parseIP(body string) (*net.IPNet, error) {
 	ip, ipnet, err := net.ParseCIDR(string(body))
 	if err != nil {

ipam/http.go

@@ -87,7 +87,7 @@ func (alloc *Allocator) handleHTTPClaim(dockerCli *docker.Client, w http.Respons
 }
 
 // HandleHTTP wires up ipams HTTP endpoints to the provided mux.
-func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CIDR, dockerCli *docker.Client) {
+func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CIDR, tracker string, dockerCli *docker.Client) {
 	router.Methods("GET").Path("/ipinfo/defaultsubnet").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintf(w, "%s", defaultSubnet)
 	})
@@ -174,4 +174,8 @@ func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CID
 		transferred := alloc.AdminTakeoverRanges(ident)
 		fmt.Fprintf(w, "%d IPs taken over from %s\n", transferred, ident)
 	})
+
+	router.Methods("GET").Path("/ipinfo/tracker").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, tracker)
+	})
 }

ipam/http_test.go

@@ -43,7 +43,7 @@ func listenHTTP(alloc *Allocator, subnet address.CIDR) int {
 	router.HandleFunc("/status", func(w http.ResponseWriter, r *http.Request) {
 		io.WriteString(w, fmt.Sprintln(alloc))
 	})
-	alloc.HandleHTTP(router, subnet, nil)
+	alloc.HandleHTTP(router, subnet, "", nil)
 
 	httpListener, err := net.Listen("tcp", ":0")
 	if err != nil {

prog/weaver/main.go

@@ -303,6 +303,7 @@ func main() {
 	var (
 		allocator     *ipam.Allocator
 		defaultSubnet address.CIDR
+		trackerName   string
 	)
 	if ipamConfig.Enabled() {
 		var t tracker.LocalRangeTracker
@@ -312,6 +313,7 @@ func main() {
 			if err != nil {
 				Log.Fatalf("Cannot create AWSVPC LocalRangeTracker: %s", err)
 			}
+			trackerName = "awsvpc"
 		}
 		allocator, defaultSubnet = createAllocator(router, ipamConfig, db, t, isKnownPeer)
 		observeContainers(allocator)
@@ -344,7 +346,7 @@ func main() {
 	if httpAddr != "" {
 		muxRouter := mux.NewRouter()
 		if allocator != nil {
-			allocator.HandleHTTP(muxRouter, defaultSubnet, dockerCli)
+			allocator.HandleHTTP(muxRouter, defaultSubnet, trackerName, dockerCli)
 		}
 		if ns != nil {
 			ns.HandleHTTP(muxRouter, dockerCli)