Workflow._fail_workflow() may fail if "output_on_error" is not empty

[Renat Akhmerov]

The method looks like (with the beginning omitted):

    def _fail_workflow(self, final_context, msg):
        ....

        # When we set an ERROR state we should safely set output value getting
        # w/o exceptions due to field size limitations.
        msg = utils.cut_by_kb(
            msg,
            cfg.CONF.engine.execution_field_size_limit_kb
        )

        self.wf_ex.output = merge_dicts({'result': msg}, output_on_error)

        if self.wf_ex.task_execution_id:
            self._schedule_send_result_to_parent_workflow()

So, we first use utils.cut_by_kb() for "msg" but then, essentially, add 'output_on_error' to it so the resulting size of 'output' may be greater than cfg.CONF.engine.execution_field_size_limit_kb

[Renat Akhmerov (rakhmerov)]

The right fix seems to be the following:
* Calculate size of "output_on_error".
* If it's greater than config option:
** Log the full message and "output_on_error"
** Raise an exception (we can't ignore configuration)
* If it's less:
** Log the full message
** Cut "msg" according what's left after counting "output_on_error".

[Ritesh Paiboina (rsritesh)]

Hello Renant,

Can you describe how can I reproduce a scenario where workflow is a failure and this function is being called Workflow._fail_workflow()

Perhaps any command or rest api call , this help to understand better what is going inside this function
Workflow._fail_workflow()

Accordingly I can also write a test case for this.

Thank you
Ritesh

[Renat Akhmerov (rakhmerov)]

Hi,

You should run a workflow like this:

wf:
  output-on-error: <some not empty content (e.g. YAQL expression)>
  tasks:
    task1:
      ... <it should fail so that the workflow fails too and triggers "output-on-error" clause>

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/490414
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=5691ddf94af6bb34b052c9ff2e9dbfa4567ee79d
Submitter: Zuul
Branch: master

commit 5691ddf94af6bb34b052c9ff2e9dbfa4567ee79d
Author: rsritesh <email address hidden>
Date: Thu Aug 3 12:21:02 2017 +0200

    Consider size of output_on_error

    While printing the output of a execution
    size of output_on_error is not considered
    with the field_size_limit_kb

    This patch udpates the function to include
    the logical calculation of total size limit

    Closes-Bug: #1690316
    Change-Id: Icab63d147f580b8d72d8c02b3d9261fd64d3438a

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/mistral 6.0.0.0rc1 release candidate.