Scaffold admin app

pkg/proxy/net.go

@@ -0,0 +1,47 @@
+package proxy
+
+import (
+	"errors"
+	"net"
+)
+
+var ErrAlreadyAccepted = errors.New("listener already accepted")
+
+// OnceListener implements net.Listener.
+//
+// Accepts a connection once and returns an error on subsequent
+// attempts.
+type OnceAcceptListener struct {
+	c net.Conn
+}
+
+func (l *OnceAcceptListener) Accept() (net.Conn, error) {
+	if l.c == nil {
+		return nil, ErrAlreadyAccepted
+	}
+
+	c := l.c
+	l.c = nil
+
+	return c, nil
+}
+
+func (l *OnceAcceptListener) Close() error {
+	return nil
+}
+
+func (l *OnceAcceptListener) Addr() net.Addr {
+	return l.c.LocalAddr()
+}
+
+// ConnNotify embeds net.Conn and adds a channel field for notifying
+// that the connection was closed.
+type ConnNotify struct {
+	net.Conn
+	closed chan struct{}
+}
+
+func (c *ConnNotify) Close() {
+	c.Conn.Close()
+	c.closed <- struct{}{}
+}