chore: tunnel recorder & slight refactor

tunnel/http_forwarder.go

@@ -0,0 +1,132 @@
+package tunnel
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+	"net/http/httputil"
+	"net/url"
+	"sync"
+
+	"reichard.io/conduit/store"
+)
+
+func newHTTPForwarder(targetURL *url.URL, tunnelStore store.TunnelStore) (Forwarder, error) {
+	return &httpConnBuilder{
+		multiConnListener: newMultiConnListener(),
+		tunnelStore:       tunnelStore,
+		targetURL:         targetURL,
+	}, nil
+}
+
+type httpConnBuilder struct {
+	multiConnListener *multiConnListener
+	tunnelStore       store.TunnelStore
+	targetURL         *url.URL
+}
+
+func (c *httpConnBuilder) Type() ForwarderType {
+	return ForwarderHTTP
+}
+
+func (c *httpConnBuilder) Start(ctx context.Context) error {
+	// Create Reverse Proxy Server
+	server := &http.Server{
+		Handler: &httputil.ReverseProxy{
+			Director: func(req *http.Request) {
+				req.Host = c.targetURL.Host
+				req.URL.Host = c.targetURL.Host
+				req.URL.Scheme = c.targetURL.Scheme
+				c.tunnelStore.RecordRequest(req)
+			},
+			ModifyResponse: c.tunnelStore.RecordResponse,
+			ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
+				http.Error(w, fmt.Sprintf("Proxy error: %v", err), http.StatusBadGateway)
+			},
+		},
+	}
+
+	// Context & Cleanup
+	go func() {
+		<-ctx.Done()
+		server.Shutdown(ctx)
+		c.multiConnListener.Close()
+	}()
+
+	// Start HTTP Proxy
+	if err := server.Serve(c.multiConnListener); err != nil && err != http.ErrServerClosed {
+		return err
+	}
+	return nil
+}
+
+func (c *httpConnBuilder) Initialize() (Stream, error) {
+	clientConn, serverConn := net.Pipe()
+
+	if err := c.multiConnListener.addConn(serverConn); err != nil {
+		_ = clientConn.Close()
+		_ = serverConn.Close()
+		return nil, err
+	}
+
+	return &streamImpl{clientConn, c.targetURL.String()}, nil
+}
+
+type multiConnListener struct {
+	connCh chan net.Conn
+	closed chan struct{}
+	once   sync.Once
+}
+
+func newMultiConnListener() *multiConnListener {
+	return &multiConnListener{
+		connCh: make(chan net.Conn, 100),
+		closed: make(chan struct{}),
+	}
+}
+
+func (l *multiConnListener) Accept() (net.Conn, error) {
+	select {
+	case conn := <-l.connCh:
+		if conn == nil {
+			return nil, fmt.Errorf("listener closed")
+		}
+		return conn, nil
+	case <-l.closed:
+		return nil, fmt.Errorf("listener closed")
+	}
+}
+
+func (l *multiConnListener) Close() error {
+	l.once.Do(func() {
+		close(l.closed)
+		// Drain any remaining connections
+		go func() {
+			for conn := range l.connCh {
+				if conn != nil {
+					conn.Close()
+				}
+			}
+		}()
+		close(l.connCh)
+	})
+	return nil
+}
+
+func (l *multiConnListener) Addr() net.Addr {
+	return &net.TCPAddr{IP: net.IPv4(127, 0, 0, 1), Port: 0}
+}
+
+func (l *multiConnListener) addConn(conn net.Conn) error {
+	select {
+	case l.connCh <- conn:
+		return nil
+	case <-l.closed:
+		conn.Close()
+		return fmt.Errorf("listener is closed")
+	default:
+		conn.Close()
+		return fmt.Errorf("connection queue full")
+	}
+}