carto: present API InternalServerError to the user, instead of failing

app/controllers/champs/carte_controller.rb

@@ -74,5 +74,9 @@ class Champs::CarteController < ApplicationController
     if @champ.persisted?
       @champ.save
     end
+
+  rescue RestClient::ResourceNotFound
+    flash.alert = 'Les données cartographiques sont temporairement indisponibles. Réessayez dans un instant.'
+    response.status = 503
   end
 end

app/lib/api_carto/api.rb

@@ -13,10 +13,10 @@ class ApiCarto::API
 
   def self.call(url, geojson)
     params = geojson.to_s
-
     RestClient.post(url, params, content_type: 'application/json')
 
-  rescue RestClient::InternalServerError
+  rescue RestClient::InternalServerError => e
+    Rails.logger.error "[ApiCarto] Error on #{url}: #{e}"
     raise RestClient::ResourceNotFound
   end
 end

app/views/champs/carte/show.js.erb

@@ -1,3 +1,5 @@
+<%= render_flash(timeout: 5000, fixed: true) %>
+
 <%= render_to_element("#{@selector} + .geo-areas",
   partial: 'shared/champs/carte/geo_areas',
   locals: { champ: @champ, error: @error }) %>