Cleanup server env settings (#3670)

Co-authored-by: Robert Kaussow <mail@thegeeklab.de>
Co-authored-by: Robert Kaussow <xoxys@rknet.org>

server/forge/gitlab/gitlab.go

@@ -51,6 +51,7 @@ type Opts struct {
 	ClientID     string // Oauth2 client id.
 	ClientSecret string // Oauth2 client secret.
 	SkipVerify   bool   // Skip ssl verification.
+	OAuthHost    string // Public url for oauth if different from url.
 }
 
 // Gitlab implements "Forge" interface.
@@ -61,6 +62,7 @@ type GitLab struct {
 	SkipVerify   bool
 	HideArchives bool
 	Search       bool
+	oAuthHost    string
 }
 
 // New returns a Forge implementation that integrates with Gitlab, an open
@@ -70,6 +72,7 @@ func New(opts Opts) (forge.Forge, error) {
 		url:          opts.URL,
 		ClientID:     opts.ClientID,
 		ClientSecret: opts.ClientSecret,
+		oAuthHost:    opts.OAuthHost,
 		SkipVerify:   opts.SkipVerify,
 		HideArchives: true,
 	}, nil
@@ -86,11 +89,16 @@ func (g *GitLab) URL() string {
 }
 
 func (g *GitLab) oauth2Config(ctx context.Context) (*oauth2.Config, context.Context) {
+	publicOAuthURL := g.oAuthHost
+	if publicOAuthURL == "" {
+		publicOAuthURL = g.url
+	}
+
 	return &oauth2.Config{
 			ClientID:     g.ClientID,
 			ClientSecret: g.ClientSecret,
 			Endpoint: oauth2.Endpoint{
-				AuthURL:  fmt.Sprintf("%s/oauth/authorize", g.url),
+				AuthURL:  fmt.Sprintf("%s/oauth/authorize", publicOAuthURL),
 				TokenURL: fmt.Sprintf("%s/oauth/token", g.url),
 			},
 			Scopes:      []string{defaultScope},