Do not raise NEW exceptions

Raising NEW exception is bad practice, because we lose TraceBack.
So all places like:

except SomeException as e:
    raise e

should be replaced by

except SomeException:
    raise

If we are doing some other actions before reraising we should
store information about exception then do all actions and then
reraise it. This is caused by eventlet bug. It lost information
about exception if it switch threads.

fixes bug 1191730

Change-Id: I047e355607318bf9fa6208c2b174b7cc394297f0

glance/api/v1/upload_utils.py

@@ -19,6 +19,7 @@
 import webob.exc
 
 from glance.common import exception
+from glance.openstack.common import excutils
 from glance.common import utils
 import glance.openstack.common.log as logging
 import glance.registry.client.v1.api as registry
@@ -166,14 +167,14 @@ def _kill_mismatched(image_meta, attr, actual):
                                                   request=req,
                                                   content_type='text/plain')
 
-    except webob.exc.HTTPError as e:
-        LOG.exception(_("Received HTTP error while uploading image."))
-        safe_kill(req, image_id)
+    except webob.exc.HTTPError:
         #NOTE(bcwaldon): Ideally, we would just call 'raise' here,
         # but something in the above function calls is affecting the
         # exception context and we must explicitly re-raise the
         # caught exception.
-        raise e
+        with excutils.save_and_reraise_exception():
+            LOG.exception(_("Received HTTP error while uploading image."))
+            safe_kill(req, image_id)
 
     except Exception as e:
         msg = _("Failed to upload image")

glance/common/exception.py

@@ -43,9 +43,9 @@ def __init__(self, message=None, *args, **kwargs):
             message = self.message
         try:
             message = message % kwargs
-        except Exception as e:
+        except Exception:
             if _FATAL_EXCEPTION_FORMAT_ERRORS:
-                raise e
+                raise
             else:
                 # at least get the core message out if something happened
                 pass

glance/common/rpc.py

@@ -151,7 +151,7 @@ def validate(cmd):
                 result = method(req.context, **kwargs)
             except Exception as e:
                 if self.raise_exc:
-                    raise e
+                    raise
 
                 cls, val = e.__class__, str(e)
                 msg = (_("RPC Call Error: %(val)s\n%(tb)s") %