openstack
/
nova
Code Issues Proposed changes

Stop using LoopingCall in nova.virt.xenapi_conn:wait_for_task() 

The use of utils.LoopingCall is unnecessary since code waits immediately
for the LoopingCall to finish. This results in code that is more
complicated than necessary, but also it creates an extra greenthread
that ends up obfuscating stack trace in case of exceptions.

Change-Id: Iaf0909a4f2307e8657e7baa15cb5a7852ba6feca
This commit is contained in:
Johannes Erdfelt 2012-02-08 22:28:18 +00:00
parent 85ae58c21f
commit 6ab291fb54
1 changed files with 30 additions and 40 deletions
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70
nova/virt/xenapi_conn.py
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@ -65,7 +65,7 @@ import time
import urlparse
import xmlrpclib
from eventlet import event
from eventlet import greenthread
from eventlet import queue
from eventlet import tpool
from eventlet import timeout
@ -563,54 +563,44 @@ class XenAPISession(object):
def wait_for_task(self, task, uuid=None):
"""Return the result of the given task. The task is polled
until it completes."""
done = event.Event()
loop = utils.LoopingCall(f=None)
def _poll_task():
while True:
"""Poll the given XenAPI task, and return the result if the
action was completed successfully or not.
"""
try:
ctxt = context.get_admin_context()
name = self.call_xenapi("task.get_name_label", task)
status = self.call_xenapi("task.get_status", task)
ctxt = context.get_admin_context()
name = self.call_xenapi("task.get_name_label", task)
status = self.call_xenapi("task.get_status", task)
# Ensure action is never > 255
action = dict(action=name[:255], error=None)
log_instance_actions = (FLAGS.xenapi_log_instance_actions and
uuid)
if log_instance_actions:
action["instance_uuid"] = uuid
if status == "pending":
pass
elif status == "success":
result = self.call_xenapi("task.get_result", task)
LOG.info(_("Task [%(name)s] %(task)s status:"
" success %(result)s") % locals())
# Ensure action is never > 255
action = dict(action=name[:255], error=None)
log_instance_actions = (FLAGS.xenapi_log_instance_actions and
uuid)
if log_instance_actions:
action["instance_uuid"] = uuid
db.instance_action_create(ctxt, action)
if status == "pending":
return
elif status == "success":
result = self.call_xenapi("task.get_result", task)
LOG.info(_("Task [%(name)s] %(task)s status:"
" success %(result)s") % locals())
return _parse_xmlrpc_value(result)
else:
error_info = self.call_xenapi("task.get_error_info", task)
LOG.warn(_("Task [%(name)s] %(task)s status:"
" %(status)s %(error_info)s") % locals())
if log_instance_actions:
db.instance_action_create(ctxt, action)
if log_instance_actions:
action["error"] = str(error_info)
db.instance_action_create(ctxt, action)
done.send(_parse_xmlrpc_value(result))
else:
error_info = self.call_xenapi("task.get_error_info", task)
LOG.warn(_("Task [%(name)s] %(task)s status:"
" %(status)s %(error_info)s") % locals())
raise self.XenAPI.Failure(error_info)
if log_instance_actions:
action["error"] = str(error_info)
db.instance_action_create(ctxt, action)
done.send_exception(self.XenAPI.Failure(error_info))
except self.XenAPI.Failure, exc:
LOG.warn(exc)
done.send_exception(*sys.exc_info())
loop.stop()
loop.f = _poll_task
loop.start(FLAGS.xenapi_task_poll_interval, now=True)
return done.wait()
greenthread.sleep(FLAGS.xenapi_task_poll_interval)
def _create_session(self, url):
"""Stubout point. This can be replaced with a mock session."""