Improve error messages when DeepL quota is exceeded (#26704)

app/controllers/api/v1/statuses/translations_controller.rb

@@ -8,7 +8,15 @@ class Api::V1::Statuses::TranslationsController < Api::BaseController
   before_action :set_translation
 
   rescue_from TranslationService::NotConfiguredError, with: :not_found
-  rescue_from TranslationService::UnexpectedResponseError, TranslationService::QuotaExceededError, TranslationService::TooManyRequestsError, with: :service_unavailable
+  rescue_from TranslationService::UnexpectedResponseError, with: :service_unavailable
+
+  rescue_from TranslationService::QuotaExceededError do
+    render json: { error: I18n.t('translation.errors.quota_exceeded') }, status: 503
+  end
+
+  rescue_from TranslationService::TooManyRequestsError do
+    render json: { error: I18n.t('translation.errors.too_many_requests') }, status: 503
+  end
 
   def create
     render json: @translation, serializer: REST::TranslationSerializer

config/locales/en.yml

@@ -1709,6 +1709,10 @@ en:
       default: "%b %d, %Y, %H:%M"
       month: "%b %Y"
       time: "%H:%M"
+  translation:
+    errors:
+      quota_exceeded: The server-wide usage quota for the translation service has been exceeded.
+      too_many_requests: There have been too many requests to the translation service recently.
   two_factor_authentication:
     add: Add
     disable: Disable 2FA