FIX: nfv event list failed with internal server error

In case of invalid id of resource-id, event list command failed
with inappropriate error(i.e. internal server error). Fixing this issue
with propper error handling.

Change-Id: I0e23da2d63bf3bcedfea78e6e88575cb7a7adfeb
Closes-Bug:#1834178

tacker/db/common_services/common_services_db_plugin.py

@@ -16,6 +16,7 @@
 
 from sqlalchemy.orm import exc as orm_exc
 
+from oslo_db import exception
 from oslo_log import log as logging
 
 from tacker.common import log
@@ -82,7 +83,12 @@ class CommonServicesPluginDb(common_services.CommonServicesPluginBase,
     @log.log
     def get_events(self, context, filters=None, fields=None, sorts=None,
                    limit=None, marker_obj=None, page_reverse=False):
+        try:
             return self._get_collection(context, common_services_db.Event,
                                         self._make_event_dict,
                                         filters, fields, sorts, limit,
                                         marker_obj, page_reverse)
+        except exception.DBError as e:
+            LOG.error("Failed to get event: %s", e.message)
+            msg = "Id should be in UUID v4 format"
+            raise common_services.InvalidFormat(error=msg)

tacker/extensions/common_services.py

@@ -46,6 +46,10 @@ class ParamYAMLInputMissing(exceptions.InvalidInput):
     message = _("Parameter YAML input missing")
 
 
+class InvalidFormat(exceptions.InvalidInput):
+    message = _("Invalid format. '%(error)s'")
+
+
 RESOURCE_ATTRIBUTE_MAP = {
 
     'events': {