improve web socket error logging

pkg/remotedialer/client.go

@@ -2,6 +2,7 @@ package remotedialer
 
 import (
 	"context"
+	"io/ioutil"
 	"net/http"
 	"time"
 
@@ -24,12 +25,18 @@ func connectToProxy(proxyURL string, headers http.Header, auth ConnectAuthorizer
 	if dialer == nil {
 		dialer = &websocket.Dialer{HandshakeTimeout: 10 * time.Second}
 	}
-	ws, _, err := dialer.Dial(proxyURL, headers)
+	ws, resp, err := dialer.Dial(proxyURL, headers)
 	if err != nil {
-		logrus.WithError(err).Error("Failed to connect to proxy")
+		rb, err2 := ioutil.ReadAll(resp.Body)
+		if err2 != nil {
+			logrus.WithError(err).Errorf("Failed to connect to proxy. Response status: %v - %v. Couldn't read response body (err: %v)", resp.StatusCode, resp.Status, err2)
+		} else {
+			logrus.WithError(err).Errorf("Failed to connect to proxy. Response status: %v - %v. Response body: %s", resp.StatusCode, resp.Status, rb)
+		}
 		return err
 	}
 	defer ws.Close()
+	defer resp.Body.Close()
 
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()