Extract interface util functions to their own file

server/if_utils.go

@@ -0,0 +1,35 @@
+package weavedns
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"time"
+)
+
+func ensureInterface(ifaceName string, wait int) (iface *net.Interface, err error) {
+	iface, err = findInterface(ifaceName)
+	if err == nil || wait == 0 {
+		return
+	}
+	log.Println("Waiting for interface", ifaceName, "to come up")
+	for ; err != nil && wait > 0; wait -= 1 {
+		time.Sleep(1 * time.Second)
+		iface, err = findInterface(ifaceName)
+	}
+	if err == nil {
+		log.Println("Interface", ifaceName, "is up")
+	}
+	return
+}
+
+func findInterface(ifaceName string) (iface *net.Interface, err error) {
+	iface, err = net.InterfaceByName(ifaceName)
+	if err != nil {
+		return iface, fmt.Errorf("Unable to find interface %s", ifaceName)
+	}
+	if 0 == (net.FlagUp & iface.Flags) {
+		return iface, fmt.Errorf("Interface %s is not up", ifaceName)
+	}
+	return
+}

server/server.go

@@ -5,40 +5,12 @@ import (
 	"github.com/miekg/dns"
 	"log"
 	"net"
-	"time"
 )
 
 const (
 	LOCAL_DOMAIN = "weave"
 )
 
-func ensureInterface(ifaceName string, wait int) (iface *net.Interface, err error) {
-	iface, err = findInterface(ifaceName)
-	if err == nil || wait == 0 {
-		return
-	}
-	log.Println("Waiting for interface", ifaceName, "to come up")
-	for ; err != nil && wait > 0; wait -= 1 {
-		time.Sleep(1 * time.Second)
-		iface, err = findInterface(ifaceName)
-	}
-	if err == nil {
-		log.Println("Interface", ifaceName, "is up")
-	}
-	return
-}
-
-func findInterface(ifaceName string) (iface *net.Interface, err error) {
-	iface, err = net.InterfaceByName(ifaceName)
-	if err != nil {
-		return iface, fmt.Errorf("Unable to find interface %s", ifaceName)
-	}
-	if 0 == (net.FlagUp & iface.Flags) {
-		return iface, fmt.Errorf("Interface %s is not up", ifaceName)
-	}
-	return
-}
-
 func makeDNSFailResponse(r *dns.Msg) *dns.Msg {
 	m := new(dns.Msg)
 	m.SetReply(r)