refactor(portfwd): enable listener injection for tests

Signed-off-by: Casey Quinn <casey.quinn@agyn.io>

Author: casey-quinn

pkg/portfwd/forward.go

@@ -18,23 +18,36 @@ import (
 var IPv4loopback1 = limayaml.IPv4loopback1
 
 type Forwarder struct {
-	rules             []limatype.PortForward
-	ignoreTCP         bool
-	ignoreUDP         bool
-	closableListeners *ClosableListeners
+	rules     []limatype.PortForward
+	ignoreTCP bool
+	ignoreUDP bool
+	listeners listenerManager
 }
 
 func NewPortForwarder(rules []limatype.PortForward, ignoreTCP, ignoreUDP bool) *Forwarder {
+	return newPortForwarderWithManager(rules, ignoreTCP, ignoreUDP, NewClosableListener())
+}
+
+type listenerManager interface {
+	Forward(ctx context.Context, dialContext func(ctx context.Context, network string, addr string) (net.Conn, error), protocol, hostAddress, guestAddress string)
+	Remove(ctx context.Context, protocol, hostAddress, guestAddress string)
+	Close() error
+}
+
+func newPortForwarderWithManager(rules []limatype.PortForward, ignoreTCP, ignoreUDP bool, mgr listenerManager) *Forwarder {
 	return &Forwarder{
-		rules:             rules,
-		ignoreTCP:         ignoreTCP,
-		ignoreUDP:         ignoreUDP,
-		closableListeners: NewClosableListener(),
+		rules:     rules,
+		ignoreTCP: ignoreTCP,
+		ignoreUDP: ignoreUDP,
+		listeners: mgr,
 	}
 }
 
 func (fw *Forwarder) Close() error {
-	return fw.closableListeners.Close()
+	if fw.listeners == nil {
+		return nil
+	}
+	return fw.listeners.Close()
 }
 
 func (fw *Forwarder) OnEvent(ctx context.Context, dialContext func(ctx context.Context, network string, addr string) (net.Conn, error), ev *api.Event) {
@@ -57,7 +70,7 @@ func (fw *Forwarder) OnEvent(ctx context.Context, dialContext func(ctx context.C
 			continue
 		}
 		logrus.Infof("Forwarding %s from %s to %s", strings.ToUpper(f.Protocol), remote, local)
-		fw.closableListeners.Forward(ctx, dialContext, f.Protocol, local, remote)
+		fw.listeners.Forward(ctx, dialContext, f.Protocol, local, remote)
 	}
 	for _, f := range ev.RemovedLocalPorts {
 		if fw.shouldIgnoreProtocol(f.Protocol) {
@@ -67,7 +80,7 @@ func (fw *Forwarder) OnEvent(ctx context.Context, dialContext func(ctx context.C
 		if local == "" {
 			continue
 		}
-		fw.closableListeners.Remove(ctx, f.Protocol, local, remote)
+		fw.listeners.Remove(ctx, f.Protocol, local, remote)
 		logrus.Debugf("Port forwarding closed proto:%s host:%s guest:%s", f.Protocol, local, remote)
 	}
 }