++ exception handling

scripts/uncloud

@@ -8,6 +8,7 @@ import sys
 from logging.handlers import SysLogHandler
 from uncloud.configure.main import configure_parser
 
+from uncloud import UncloudException
 
 def exception_hook(exc_type, exc_value, exc_traceback):
     logging.getLogger(__name__).error(
@@ -61,5 +62,7 @@ if __name__ == '__main__':
             mod = importlib.import_module("uncloud.{}.main".format(name))
             main = getattr(mod, "main")
             main(**arguments)
+        except UncloudException as err:
+            logger.error(err)
         except Exception as err:
             logger.exception(err)

uncloud/__init__.py

@@ -0,0 +1,2 @@
+class UncloudException(Exception):
+    pass

uncloud/common/etcd_wrapper.py

@@ -2,6 +2,7 @@ import etcd3
 import json
 import queue
 import copy
+from uncloud import UncloudException
 
 from collections import namedtuple
 from functools import wraps
@@ -29,9 +30,9 @@ def readable_errors(func):
         try:
             return func(*args, **kwargs)
         except etcd3.exceptions.ConnectionFailedError as err:
-            raise etcd3.exceptions.ConnectionFailedError(
-                "etcd connection failed."
-            ) from err
+            raise UncloudException(
+                "Cannot connect to etcd: is etcd running as configured in uncloud.conf?"
+            )
         except etcd3.exceptions.ConnectionTimeoutError as err:
             raise etcd3.exceptions.ConnectionTimeoutError(
                 "etcd connection timeout."