Make error notifications more consistent.

The error notifications sent by wrap_exception are a good source of
information when tracking down errors in the system. It is easy to spot
patterns in the errors by looking at similarities in the exceptions
raised.

This change looks at making the in-line error notifications
follow the same format, so they become equally useful.

Closes-Bug: #1251602
Change-Id: I1cd64a90ecefc64d12af05487eb6e45aa0362d69

nova/compute/utils.py

@@ -39,12 +39,11 @@ CONF.import_opt('host', 'nova.netconf')
 LOG = log.getLogger(__name__)
 
 
-def add_instance_fault_from_exc(context, conductor,
-                                instance, fault, exc_info=None):
-    """Adds the specified fault to the database."""
+def exception_to_dict(fault):
+    """Converts exceptions to a dict for use in notifications."""
+    #TODO(johngarbutt) move to nova/exception.py to share with wrap_exception
 
     code = 500
-
     if hasattr(fault, "kwargs"):
         code = fault.kwargs.get('code', 500)
 
@@ -65,17 +64,35 @@ def add_instance_fault_from_exc(context, conductor,
     # MySQL silently truncates overly long messages, but PostgreSQL throws an
     # error if we don't truncate it.
     u_message = unicode(message)[:255]
-    details = ''
 
-    if exc_info and code == 500:
+    fault_dict = dict(exception=fault)
+    fault_dict["message"] = u_message
+    fault_dict["code"] = code
+    return fault_dict
+
+
+def _get_fault_details(exc_info, error_code):
+    details = ''
+    if exc_info and error_code == 500:
         tb = exc_info[2]
-        details += ''.join(traceback.format_tb(tb))
+        if tb:
+            details = ''.join(traceback.format_tb(tb))
+    return unicode(details)
+
+
+def add_instance_fault_from_exc(context, conductor,
+                                instance, fault, exc_info=None):
+    """Adds the specified fault to the database."""
+
+    fault_dict = exception_to_dict(fault)
+    code = fault_dict["code"]
+    details = _get_fault_details(exc_info, code)
 
     values = {
         'instance_uuid': instance['uuid'],
         'code': code,
-        'message': u_message,
-        'details': unicode(details),
+        'message': fault_dict["message"],
+        'details': details,
         'host': CONF.host
     }
     conductor.instance_fault_create(context, values)
@@ -294,7 +311,7 @@ def notify_usage_exists(notifier, context, instance_ref, current_period=False,
 
 def notify_about_instance_usage(notifier, context, instance, event_suffix,
                                 network_info=None, system_metadata=None,
-                                extra_usage_info=None):
+                                extra_usage_info=None, fault=None):
     """Send a notification about an instance.
 
     :param notifier: a messaging.Notifier
@@ -311,6 +328,13 @@ def notify_about_instance_usage(notifier, context, instance, event_suffix,
     usage_info = notifications.info_from_instance(context, instance,
             network_info, system_metadata, **extra_usage_info)
 
+    if fault:
+        # NOTE(johngarbutt) mirrors the format in wrap_exception
+        fault_payload = exception_to_dict(fault)
+        LOG.debug(fault_payload["message"], instance=instance,
+                  exc_info=True)
+        usage_info.update(fault_payload)
+
     if event_suffix.endswith("error"):
         method = notifier.error
     else: