Use compact if-with-assign statements where scoping allows

server/http.go

@@ -38,7 +38,6 @@ func ListenHttp(domain string, db Zone, port int) {
 			ident, weaveIPstr, err := parseUrl(r.URL.Path)
 			name := r.FormValue("fqdn")
 			localIPstr := r.FormValue("local_ip")
-
 			if ident == "" || weaveIPstr == "" || name == "" || localIPstr == "" {
 				reqError("Invalid request", "Invalid request: %s, %s", r.URL, r.Form)
 				return
@@ -58,10 +57,8 @@ func ListenHttp(domain string, db Zone, port int) {
 
 			if dns.IsSubDomain(domain, name) {
 				Info.Printf("Adding %s (%s) -> %s", name, localIPstr, weaveIPstr)
-				err = db.AddRecord(ident, name, localIP, weaveIP)
-				if err != nil {
-					dup, ok := err.(DuplicateError)
-					if !ok {
+				if err = db.AddRecord(ident, name, localIP, weaveIP); err != nil {
+					if dup, ok := err.(DuplicateError); !ok {
 						httpErrorAndLog(
 							Error, w, "Internal error", http.StatusInternalServerError,
 							"Unexpected error from DB: %s", err)
@@ -88,8 +85,7 @@ func ListenHttp(domain string, db Zone, port int) {
 				return
 			}
 			Info.Printf("Deleting %s (%s)", ident, weaveIPstr)
-			err = db.DeleteRecord(ident, weaveIP)
-			if err != nil {
+			if err = db.DeleteRecord(ident, weaveIP); err != nil {
 				if _, ok := err.(LookupError); !ok {
 					httpErrorAndLog(
 						Error, w, "Internal error", http.StatusInternalServerError,
@@ -105,8 +101,7 @@ func ListenHttp(domain string, db Zone, port int) {
 	})
 
 	address := fmt.Sprintf(":%d", port)
-	err := http.ListenAndServe(address, nil)
-	if err != nil {
+	if err := http.ListenAndServe(address, nil); err != nil {
 		Error.Fatal("Unable to create http listener: ", err)
 	}
 }

server/if_utils.go

@@ -7,8 +7,7 @@ import (
 )
 
 func EnsureInterface(ifaceName string, wait int) (iface *net.Interface, err error) {
-	iface, err = findInterface(ifaceName)
-	if err == nil || wait == 0 {
+	if iface, err = findInterface(ifaceName); err == nil || wait == 0 {
 		return
 	}
 	Info.Println("Waiting for interface", ifaceName, "to come up")
@@ -23,8 +22,7 @@ func EnsureInterface(ifaceName string, wait int) (iface *net.Interface, err erro
 }
 
 func findInterface(ifaceName string) (iface *net.Interface, err error) {
-	iface, err = net.InterfaceByName(ifaceName)
-	if err != nil {
+	if iface, err = net.InterfaceByName(ifaceName); err != nil {
 		return iface, fmt.Errorf("Unable to find interface %s", ifaceName)
 	}
 	if 0 == (net.FlagUp & iface.Flags) {

server/mdns_client.go

@@ -62,14 +62,14 @@ type mDNSQueryInfo struct {
 }
 
 func NewMDNSClient() (*MDNSClient, error) {
-	conn, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
-	if err != nil {
+	if conn, err := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0}); err != nil {
 		return nil, err
+	} else {
+		return &MDNSClient{
+			conn:     conn,
+			addr:     ipv4Addr,
+			inflight: make(map[string]*inflightQuery)}, nil
 	}
-	return &MDNSClient{
-		conn:     conn,
-		addr:     ipv4Addr,
-		inflight: make(map[string]*inflightQuery)}, nil
 }
 
 func (c *MDNSClient) Start(ifi *net.Interface) error {
@@ -96,8 +96,7 @@ func (c *MDNSClient) Start(ifi *net.Interface) error {
 }
 
 func LinkLocalMulticastListener(ifi *net.Interface) (net.PacketConn, error) {
-	conn, err := net.ListenMulticastUDP("udp", ifi, ipv4Addr)
-	return conn, err
+	return net.ListenMulticastUDP("udp", ifi, ipv4Addr)
 }
 
 // ACTOR client API
@@ -216,8 +215,7 @@ func (c *MDNSClient) handleSendQuery(q mDNSQueryInfo) {
 			name: q.name,
 			id:   m.Id,
 		}
-		_, err = c.conn.WriteTo(buf, c.addr)
-		if err != nil {
+		if _, err = c.conn.WriteTo(buf, c.addr); err != nil {
 			q.responseCh <- &ResponseA{Err: err}
 			close(q.responseCh)
 			return

server/mdns_server.go

@@ -17,9 +17,7 @@ func NewMDNSServer(zone Zone) (*MDNSServer, error) {
 	if err != nil {
 		return nil, err
 	}
-	retval := &MDNSServer{sendconn: sendconn, zone: zone}
-
-	return retval, nil
+	return &MDNSServer{sendconn: sendconn, zone: zone}, nil
 }
 
 // Return true if testaddr is a UDP address with IP matching my local i/f
@@ -41,8 +39,7 @@ func (s *MDNSServer) Start(ifi *net.Interface) error {
 		// Ignore answers to other questions
 		if len(r.Answer) == 0 && len(r.Question) > 0 {
 			q := r.Question[0]
-			ip, err := s.zone.MatchLocal(q.Name)
-			if err == nil {
+			if ip, err := s.zone.MatchLocal(q.Name); err == nil {
 				m := makeAReply(r, &q, []net.IP{ip})
 				s.SendResponse(m)
 			} else if s.addrIsLocal(w.RemoteAddr()) {
@@ -57,6 +54,7 @@ func (s *MDNSServer) Start(ifi *net.Interface) error {
 	if err != nil {
 		return err
 	}
+
 	if ifi == nil {
 		s.localAddrs, err = net.InterfaceAddrs()
 	} else {

server/server.go

@@ -39,8 +39,7 @@ func queryHandler(zone Zone, mdnsClient *MDNSClient) dns.HandlerFunc {
 		q := r.Question[0]
 		Debug.Printf("Local query: %+v", q)
 		if q.Qtype == dns.TypeA {
-			ip, err := zone.MatchLocal(q.Name)
-			if err == nil {
+			if ip, err := zone.MatchLocal(q.Name); err == nil {
 				m := makeAReply(r, &q, []net.IP{ip})
 				w.WriteMsg(m)
 			} else {
@@ -81,8 +80,7 @@ func rdnsHandler(zone Zone, mdnsClient *MDNSClient) dns.HandlerFunc {
 				ip4 := ip.To4()
 				revIP := []byte{ip4[3], ip4[2], ip4[1], ip4[0]}
 				Debug.Printf("Looking for address: %+v", revIP)
-				name, err := zone.MatchLocalIP(revIP)
-				if err == nil {
+				if name, err := zone.MatchLocalIP(revIP); err == nil {
 					Debug.Printf("Found name: %s", name)
 					m := makePTRReply(r, &q, []string{name})
 					w.WriteMsg(m)
@@ -106,8 +104,7 @@ func notUsHandler() dns.HandlerFunc {
 		Debug.Printf("Non-local query: %+v", q)
 		var responseMsg *dns.Msg
 		if q.Qtype == dns.TypeA {
-			addrs, err := net.LookupIP(q.Name)
-			if err == nil {
+			if addrs, err := net.LookupIP(q.Name); err == nil {
 				responseMsg = makeAReply(r, &q, addrs)
 			} else {
 				responseMsg = makeDNSFailResponse(r)