Move systemd code to linux-only built files

server/server.go

@@ -18,7 +18,6 @@ import (
 	"github.com/skynetservices/skydns/msg"
 
 	etcd "github.com/coreos/etcd/client"
-	"github.com/coreos/go-systemd/activation"
 	"github.com/miekg/dns"
 )
 
@@ -63,41 +62,9 @@ func (s *server) Run() error {
 	}
 
 	if s.config.Systemd {
-		packetConns, err := activation.PacketConns(false)
-		if err != nil {
-			return err
-		}
-		listeners, err := activation.Listeners(true)
-		if err != nil {
+		if err := s.activateSystemd(mux, dnsReadyMsg); err != nil {
 			return err
 		}
-		if len(packetConns) == 0 && len(listeners) == 0 {
-			return fmt.Errorf("no UDP or TCP sockets supplied by systemd")
-		}
-		for _, p := range packetConns {
-			if u, ok := p.(*net.UDPConn); ok {
-				s.group.Add(1)
-				go func() {
-					defer s.group.Done()
-					if err := dns.ActivateAndServe(nil, u, mux); err != nil {
-						fatalf("%s", err)
-					}
-				}()
-				dnsReadyMsg(u.LocalAddr().String(), "udp")
-			}
-		}
-		for _, l := range listeners {
-			if t, ok := l.(*net.TCPListener); ok {
-				s.group.Add(1)
-				go func() {
-					defer s.group.Done()
-					if err := dns.ActivateAndServe(t, nil, mux); err != nil {
-						fatalf("%s", err)
-					}
-				}()
-				dnsReadyMsg(t.Addr().String(), "tcp")
-			}
-		}
 	} else {
 		s.group.Add(1)
 		go func() {

server/server_linux.go

@@ -0,0 +1,48 @@
+package server
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/coreos/go-systemd/activation"
+	"github.com/miekg/dns"
+)
+
+func (s *server) activateSystemd(mux *dns.ServeMux, dnsReadyMsg func(addr, net string)) error {
+	packetConns, err := activation.PacketConns(false)
+	if err != nil {
+		return err
+	}
+	listeners, err := activation.Listeners(true)
+	if err != nil {
+		return err
+	}
+	if len(packetConns) == 0 && len(listeners) == 0 {
+		return fmt.Errorf("no UDP or TCP sockets supplied by systemd")
+	}
+	for _, p := range packetConns {
+		if u, ok := p.(*net.UDPConn); ok {
+			s.group.Add(1)
+			go func() {
+				defer s.group.Done()
+				if err := dns.ActivateAndServe(nil, u, mux); err != nil {
+					fatalf("%s", err)
+				}
+			}()
+			dnsReadyMsg(u.LocalAddr().String(), "udp")
+		}
+	}
+	for _, l := range listeners {
+		if t, ok := l.(*net.TCPListener); ok {
+			s.group.Add(1)
+			go func() {
+				defer s.group.Done()
+				if err := dns.ActivateAndServe(t, nil, mux); err != nil {
+					fatalf("%s", err)
+				}
+			}()
+			dnsReadyMsg(t.Addr().String(), "tcp")
+		}
+	}
+	return nil
+}

server/server_other.go

@@ -0,0 +1,12 @@
+// +build !linux
+
+package server
+
+import (
+	"github.com/miekg/dns"
+)
+
+func (s *server) activateSystemd(mux *dns.ServeMux, dnsReadyMsg func(addr, net string)) error {
+	// Noop on non-linux platforms
+	return nil
+}