feat: probes (#964)

* feat: probes

* feat: validate

* fix: protos

Co-authored-by: Livio Amstutz <livio.a@gmail.com>

internal/api/api.go

@@ -90,6 +90,7 @@ func (a *API) healthHandler() http.Handler {
 	handler := http.NewServeMux()
 	handler.HandleFunc("/healthz", handleHealth)
 	handler.HandleFunc("/ready", handleReadiness(checks))
+	handler.HandleFunc("/validate", handleValidate(checks))
 	handler.HandleFunc("/clientID", a.handleClientID)
 
 	return handler
@@ -102,12 +103,23 @@ func handleHealth(w http.ResponseWriter, r *http.Request) {
 
 func handleReadiness(checks []ValidationFunction) func(w http.ResponseWriter, r *http.Request) {
 	return func(w http.ResponseWriter, r *http.Request) {
-		err := validate(r.Context(), checks)
-		if err == nil {
+		errors := validate(r.Context(), checks)
+		if len(errors) == 0 {
 			http_util.MarshalJSON(w, "ok", nil, http.StatusOK)
 			return
 		}
-		http_util.MarshalJSON(w, nil, err, http.StatusPreconditionFailed)
+		http_util.MarshalJSON(w, nil, errors[0], http.StatusPreconditionFailed)
+	}
+}
+
+func handleValidate(checks []ValidationFunction) func(w http.ResponseWriter, r *http.Request) {
+	return func(w http.ResponseWriter, r *http.Request) {
+		errors := validate(r.Context(), checks)
+		if len(errors) == 0 {
+			http_util.MarshalJSON(w, "ok", nil, http.StatusOK)
+			return
+		}
+		http_util.MarshalJSON(w, errors, nil, http.StatusOK)
 	}
 }
 
@@ -122,12 +134,13 @@ func (a *API) handleClientID(w http.ResponseWriter, r *http.Request) {
 
 type ValidationFunction func(ctx context.Context) error
 
-func validate(ctx context.Context, validations []ValidationFunction) error {
+func validate(ctx context.Context, validations []ValidationFunction) []error {
+	errors := make([]error, 0)
 	for _, validation := range validations {
 		if err := validation(ctx); err != nil {
 			logging.Log("API-vf823").WithError(err).WithField("traceID", tracing.TraceIDFromCtx(ctx)).Error("validation failed")
-			return err
+			errors = append(errors, err)
 		}
 	}
-	return nil
+	return errors
 }