auth-proxy: proxies only authenticated requests to upstream, redirects to login page otherwise (#103)

* auth-proxy: inspects authenticated user

* ingress: chart and use in rpuppy

* auth-proxy: make it optional in rpuppy

* kratos: whitelist env pub/priv domains for auth return_to addr

* url-shortener: put behind auth-proxy

* pihole: replace oauth2-client with auth-proxy

* auth-proxy: fix upstream uri generation

* pihole: remove old chart using oauth2

* auth-proxy: remove temporary values file

* url-shortener: check x-user header for authentication

* auth: fix allowed_return_urls list

* auth-proxy: fix current address generation logic

---------

Co-authored-by: Giorgi Lekveishvili <lekva@gl-mbp-m1-max.local>
diff --git a/apps/url-shortener/main.go b/apps/url-shortener/main.go
index b1db1f9..bb805e4 100644
--- a/apps/url-shortener/main.go
+++ b/apps/url-shortener/main.go
@@ -157,8 +157,11 @@
 }
 
 func getLoggedInUser(r *http.Request) (string, error) {
-	// TODO(dato): should make a request to get loggedin user
-	return "tabo", nil
+	if user := r.Header.Get("X-User"); user != "" {
+		return user, nil
+	} else {
+		return "", fmt.Errorf("unauthenticated")
+	}
 }
 
 type Server struct {