fix: oauth path building (kubeshop#3991)

* fix: oauth path building

* fix paths

* replace path.Join with url.JoinPath

cli/config/config.go

@@ -44,7 +44,6 @@ type Config struct {
 
 func (c Config) OAuthEndpoint() string {
 	return fmt.Sprintf("%s%s", c.URL(), c.Path())
-
 }
 
 func (c Config) URL() string {

cli/config/configurator.go

@@ -156,6 +156,7 @@ func (c Configurator) getServerURL(prev *Config) (string, error) {
 }
 
 func (c Configurator) createConfig(serverURL string) (Config, error) {
+	serverURL = strings.TrimSuffix(serverURL, "/")
 	scheme, endpoint, path, err := ParseServerURL(serverURL)
 	if err != nil {
 		return Config{}, err

cli/pkg/oauth/oauth.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"net"
 	"net/http"
+	neturl "net/url"
 	"sync"
 
 	"github.com/kubeshop/tracetest/cli/ui"
@@ -58,7 +59,10 @@ func (s *OAuthServer) GetAuthJWT() error {
 		return fmt.Errorf("failed to start oauth server: %w", err)
 	}
 
-	loginUrl := fmt.Sprintf("%soauth?callback=%s", s.frontendEndpoint, url)
+	loginUrl, err := neturl.JoinPath(s.frontendEndpoint, fmt.Sprintf("oauth?callback=%s", url))
+	if err != nil {
+		return fmt.Errorf("could not build path: %w", err)
+	}
 
 	ui := ui.DefaultUI
 	err = ui.OpenBrowser(loginUrl)