TUN-3617: Separate service from client, and implement different client for http vs. tcp origins

- extracted ResponseWriter from proxyConnection
 - added bastion tests over websocket
 - removed HTTPResp()
 - added some docstrings
 - Renamed some ingress clients as proxies
 - renamed instances of client to proxy in connection and origin
 - Stream no longer takes a context and logger.Service

connection/connection.go

@@ -14,7 +14,7 @@ import (
 const LogFieldConnIndex = "connIndex"
 
 type Config struct {
-	OriginClient    OriginClient
+	OriginProxy     OriginProxy
 	GracePeriod     time.Duration
 	ReplaceExisting bool
 }
@@ -50,12 +50,12 @@ func (c *ClassicTunnelConfig) IsTrialZone() bool {
 	return c.Hostname == ""
 }
 
-type OriginClient interface {
+type OriginProxy interface {
 	Proxy(w ResponseWriter, req *http.Request, isWebsocket bool) error
 }
 
 type ResponseWriter interface {
-	WriteRespHeaders(*http.Response) error
+	WriteRespHeaders(status int, header http.Header) error
 	WriteErrorResponse()
 	io.ReadWriter
 }

connection/connection_test.go

@@ -19,8 +19,8 @@ const (
 
 var (
 	testConfig = &Config{
-		OriginClient: &mockOriginClient{},
-		GracePeriod:  time.Millisecond * 100,
+		OriginProxy: &mockOriginProxy{},
+		GracePeriod: time.Millisecond * 100,
 	}
 	log           = zerolog.Nop()
 	testOriginURL = &url.URL{
@@ -38,10 +38,10 @@ type testRequest struct {
 	isProxyError   bool
 }
 
-type mockOriginClient struct {
+type mockOriginProxy struct {
 }
 
-func (moc *mockOriginClient) Proxy(w ResponseWriter, r *http.Request, isWebsocket bool) error {
+func (moc *mockOriginProxy) Proxy(w ResponseWriter, r *http.Request, isWebsocket bool) error {
 	if isWebsocket {
 		return wsEndpoint(w, r)
 	}
@@ -74,7 +74,7 @@ func wsEndpoint(w ResponseWriter, r *http.Request) error {
 	resp := &http.Response{
 		StatusCode: http.StatusSwitchingProtocols,
 	}
-	_ = w.WriteRespHeaders(resp)
+	_ = w.WriteRespHeaders(resp.StatusCode, resp.Header)
 	clientReader := nowriter{r.Body}
 	go func() {
 		for {
@@ -95,7 +95,7 @@ func originRespEndpoint(w ResponseWriter, status int, data []byte) {
 	resp := &http.Response{
 		StatusCode: status,
 	}
-	_ = w.WriteRespHeaders(resp)
+	_ = w.WriteRespHeaders(resp.StatusCode, resp.Header)
 	_, _ = w.Write(data)
 }
 

connection/h2mux.go

@@ -216,7 +216,7 @@ func (h *h2muxConnection) ServeStream(stream *h2mux.MuxedStream) error {
 		return reqErr
 	}
 
-	err := h.config.OriginClient.Proxy(respWriter, req, websocket.IsWebSocketUpgrade(req))
+	err := h.config.OriginProxy.Proxy(respWriter, req, websocket.IsWebSocketUpgrade(req))
 	if err != nil {
 		respWriter.WriteErrorResponse()
 		return err
@@ -240,8 +240,8 @@ type h2muxRespWriter struct {
 	*h2mux.MuxedStream
 }
 
-func (rp *h2muxRespWriter) WriteRespHeaders(resp *http.Response) error {
-	headers := h2mux.H1ResponseToH2ResponseHeaders(resp)
+func (rp *h2muxRespWriter) WriteRespHeaders(status int, header http.Header) error {
+	headers := h2mux.H1ResponseToH2ResponseHeaders(status, header)
 	headers = append(headers, h2mux.Header{Name: ResponseMetaHeaderField, Value: responseMetaHeaderOrigin})
 	return rp.WriteHeaders(headers)
 }

connection/http2.go

@@ -115,9 +115,9 @@ func (c *http2Connection) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	} else if isWebsocketUpgrade(r) {
 		respWriter.shouldFlush = true
 		stripWebsocketUpgradeHeader(r)
-		err = c.config.OriginClient.Proxy(respWriter, r, true)
+		err = c.config.OriginProxy.Proxy(respWriter, r, true)
 	} else {
-		err = c.config.OriginClient.Proxy(respWriter, r, false)
+		err = c.config.OriginProxy.Proxy(respWriter, r, false)
 	}
 
 	if err != nil {
@@ -161,10 +161,10 @@ type http2RespWriter struct {
 	shouldFlush bool
 }
 
-func (rp *http2RespWriter) WriteRespHeaders(resp *http.Response) error {
+func (rp *http2RespWriter) WriteRespHeaders(status int, header http.Header) error {
 	dest := rp.w.Header()
-	userHeaders := make(http.Header, len(resp.Header))
-	for header, values := range resp.Header {
+	userHeaders := make(http.Header, len(header))
+	for header, values := range header {
 		// Since these are http2 headers, they're required to be lowercase
 		h2name := strings.ToLower(header)
 		for _, v := range values {
@@ -184,13 +184,12 @@ func (rp *http2RespWriter) WriteRespHeaders(resp *http.Response) error {
 	// Perform user header serialization and set them in the single header
 	dest.Set(canonicalResponseUserHeadersField, h2mux.SerializeHeaders(userHeaders))
 	rp.setResponseMetaHeader(responseMetaHeaderOrigin)
-	status := resp.StatusCode
 	// HTTP2 removes support for 101 Switching Protocols https://tools.ietf.org/html/rfc7540#section-8.1.1
 	if status == http.StatusSwitchingProtocols {
 		status = http.StatusOK
 	}
 	rp.w.WriteHeader(status)
-	if IsServerSentEvent(resp.Header) {
+	if IsServerSentEvent(header) {
 		rp.shouldFlush = true
 	}
 	if rp.shouldFlush {