[Openstack] [TaskFlow] Is there any way to retrieve the `flow_uuid` in the `Task`?

Joshua Harlow harlowja at yahoo-inc.com
Thu May 22 17:09:47 UTC 2014

Hi Timon,

A good question :)

In general tasks aren't very aware of the flow they are running in, mainly
on purpose since flows are really just a 'container' of tasks that impose
constraints on how the tasks inside it run (for example a linear_flow as u
are using imposes a linearity constraint on the tasks contained inside it).

If its still needed there are a few ways to do this. U have found one of
them, passing it in via the task constructor method. This I think is fine
if u are ok with not running those tasks later in a remote/distributed
manner (since the logger resource object can't be sent across remote

Another way to do this is to use the transient feature of the engines
storage that should be released in 0.3 (this will come out soon)[1]. This
would allow your task to have the following function definition and have
it not have to be passed in via the task constructor (instead the logger
argument will become a execution time dependency that will be grabbed from
the storage interface).

def execute(self, a, b, c, logger):

A third method is to use the listener interface and use that instead
(although this will be a less granular logging approach). There are some
examples and usage details @
d-logging-listeners that might be useful for u. Combining this listener
approach with a tasks ability to update its own status/progress[2] might
just do the trick for u.

If none of these work for u, feel free to jump on
#openstack-state-management and we can think of other ways to do this :)


[2] https://github.com/openstack/taskflow/blob/master/taskflow/task.py#L78

-----Original Message-----
From: Timon Wong <timon86.wang at gmail.com>
Date: Wednesday, May 21, 2014 at 11:17 PM
To: "openstack at lists.openstack.org" <openstack at lists.openstack.org>
Subject: [Openstack] [TaskFlow] Is there any way to retrieve the
`flow_uuid` in the `Task`?

>For logging purpose, I wanna log the `flow_uuid` as a context to
>indicate which flow the logging message related to.
>Currently, I just created a logging adapter, grab the `uuid` from the
>`flow_details`, the pass them as a constructor param like this:
>flow = linear_flow.Flow(flow_name)
>flow_detail = p_utils.create_flow_detail(flow)
>logger = create_logger_adpater(flow_detail.uuid)
>flow.add(XXXTask(logger), YYYTask(logger),ZZZTask(logger))
>Is there any better way to do that?
>Thanks in advance!
>Timon Wong
>Mailing list: 
>Post to     : openstack at lists.openstack.org
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