- Better error reporting.

- Flask now uses application's logger instead of its own.
- ucloud file scanner refactored.

ucloud/metadata/main.py

@@ -2,12 +2,27 @@ import os
 
 from flask import Flask, request
 from flask_restful import Resource, Api
+from werkzeug.exceptions import HTTPException
+
 from ucloud.settings import settings
 from ucloud.shared import shared
 
 app = Flask(__name__)
 api = Api(app)
 
+app.logger.handlers.clear()
+
+
+@app.errorhandler(Exception)
+def handle_exception(e):
+    app.logger.error(e)
+    # pass through HTTP errors
+    if isinstance(e, HTTPException):
+        return e
+
+    # now you're handling non-HTTP exceptions only
+    return {'message': 'Server Error'}, 500
+
 
 def get_vm_entry(mac_addr):
     return next(filter(lambda vm: mac_addr in list(zip(*vm.network))[1], shared.vm_pool.vms), None)