- Better error reporting.

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

ucloud/host/main.py

@@ -16,8 +16,7 @@ vmm = virtualmachine.VMM()
 def update_heartbeat(hostname):
     """Update Last HeartBeat Time for :param hostname: in etcd"""
     
-    client = shared.etcd_client
-    host_pool = HostPool(client)
+    host_pool = shared.host_pool
     this_host = next(filter(lambda h: h.hostname == hostname, host_pool.hosts), None)
 
     while True:
@@ -27,7 +26,7 @@ def update_heartbeat(hostname):
 
 
 def main(hostname):
-    host_pool = HostPool(shared.etcd_client)
+    host_pool = shared.host_pool
     host = next(filter(lambda h: h.hostname == hostname, host_pool.hosts), None)
     assert host is not None, "No such host with name = {}".format(hostname)