Extern LocalRangeTracker interface with String method

Cleaner approach than passing a tracker name to ipam/http.

ipam/allocator.go

@@ -74,6 +74,7 @@ type Allocator struct {
 	isKnownPeer       func(mesh.PeerName) bool
 	quorum            func() uint
 	now               func() time.Time
+	tracker           tracker.LocalRangeTracker
 }
 
 // PreClaims are IP addresses discovered before we could initialize IPAM
@@ -130,6 +131,7 @@ func NewAllocator(config Config) *Allocator {
 		quorum:      config.Quorum,
 		dead:        make(map[string]time.Time),
 		now:         time.Now,
+		tracker:     config.Tracker,
 	}
 
 	alloc.pendingClaims = make([]operation, len(config.PreClaims))

ipam/http.go

@@ -88,7 +88,7 @@ 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, tracker string, dockerCli *docker.Client) {
+func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CIDR, dockerCli *docker.Client) {
 	router.Methods("GET").Path("/ipinfo/defaultsubnet").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		fmt.Fprintf(w, "%s", defaultSubnet)
 	})
@@ -199,6 +199,6 @@ func (alloc *Allocator) HandleHTTP(router *mux.Router, defaultSubnet address.CID
 	})
 
 	router.Methods("GET").Path("/ipinfo/tracker").HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		fmt.Fprintf(w, tracker)
+		fmt.Fprintf(w, alloc.tracker.String())
 	})
 }

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 {

ipam/tracker/awsvpc.go

@@ -123,6 +123,10 @@ func (t *AWSVPCTracker) HandleUpdate(prevRanges, currRanges []address.Range, loc
 	return nil
 }
 
+func (t *AWSVPCTracker) String() string {
+	return "awsvpc"
+}
+
 func (t *AWSVPCTracker) createVPCRoute(cidr string) (*ec2.CreateRouteOutput, error) {
 	route := &ec2.CreateRouteInput{
 		RouteTableId:         &t.routeTableID,

ipam/tracker/tracker.go

@@ -17,4 +17,7 @@ type LocalRangeTracker interface {
 	// The local parameter indicates whether the ranges belong to the peer
 	// by which the method is called.
 	HandleUpdate(prevRanges, currRanges []address.Range, local bool) error
+
+	// String returns the tracker name
+	String() string
 }

prog/weaver/main.go

@@ -396,7 +396,6 @@ func main() {
 	var (
 		allocator     *ipam.Allocator
 		defaultSubnet address.CIDR
-		trackerName   string
 	)
 	if ipamConfig.Enabled() {
 		var t tracker.LocalRangeTracker
@@ -406,7 +405,6 @@ func main() {
 			if err != nil {
 				Log.Fatalf("Cannot create AWSVPC LocalRangeTracker: %s", err)
 			}
-			trackerName = "awsvpc"
 		}
 
 		preClaims, err := findExistingAddresses(dockerCli, bridgeConfig.WeaveBridgeName)
@@ -454,7 +452,7 @@ func main() {
 	if httpAddr != "" {
 		muxRouter := mux.NewRouter()
 		if allocator != nil {
-			allocator.HandleHTTP(muxRouter, defaultSubnet, trackerName, dockerCli)
+			allocator.HandleHTTP(muxRouter, defaultSubnet, dockerCli)
 		}
 		if ns != nil {
 			ns.HandleHTTP(muxRouter, dockerCli)