added logging in case where query required fallback

sanitiser/search_fallback.js

@@ -4,6 +4,7 @@ var sanitizeAll = require('../sanitiser/sanitizeAll'),
     };
 
 var sanitize = function(req, cb) { sanitizeAll(req, sanitizers, cb); };
+var logger = require('pelias-logger').get('api:controller:search_fallback');
 
 // middleware
 module.exports.middleware = function( req, res, next ){
@@ -14,6 +15,11 @@ module.exports.middleware = function( req, res, next ){
     return next();
   }
 
+  // log the query that caused a fallback since libpostal+new-queries didn't return anything
+  if (req.path === '/v1/search') {
+    logger.info(req.clean.text);
+  }
+
   sanitize( req, function( err, clean ){
     next();
   });