An error occurs when fetching a workflow execution

[Renat Akhmerov]

When fetching a workflow execution via API we're getting the following error:

2019-09-25 10:41:45.927 22657 ERROR wsme.api [req-67531f0e-abc2-4fee-9141-46fc40a18b56 - - - - -] Server-side error: "Parent instance <WorkflowExecution at 0x7fcbd0a67940> is not bound to a Session; lazy load operation of attribute 'root_execution' cannot proceed (Background on this error at: http://sqlalche.me/e/bhk3)". Detail:
Traceback (most recent call last):

  File "/usr/local/lib/python3.6/dist-packages/wsmeext/pecan.py", line 85, in callfunction
    result = f(self, *args, **kwargs)

  File "/opt/mistral/mistral/api/controllers/v2/execution.py", line 127, in get
    wf_ex)

  File "/opt/mistral/mistral/api/controllers/v2/execution.py", line 92, in _get_published_global_from_tasks
    published_global_vars = task.get_published_global(task_ex, wf_ex)

  File "/opt/mistral/mistral/api/controllers/v2/task.py", line 83, in get_published_global
    get_workflow_environment_dict(wf_ex),

  File "/opt/mistral/mistral/workflow/data_flow.py", line 334, in get_workflow_environment_dict
    return get_workflow_environment_dict(wf_ex.root_execution)

  File "/usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/attributes.py", line 282, in __get__
    return self.impl.get(instance_state(instance), dict_)

  File "/usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/attributes.py", line 710, in get
    value = self.callable_(state, passive)

  File "/usr/local/lib/python3.6/dist-packages/sqlalchemy/orm/strategies.py", line 688, in _load_for_state
    % (orm_util.state_str(state), self.key)

sqlalchemy.orm.exc.DetachedInstanceError: Parent instance <WorkflowExecution at 0x7fcbd0a67940> is not bound to a Session; lazy load operation of attribute 'root_execution' cannot proceed (Background on this error at: http://sqlalche.me/e/bhk3)
: sqlalchemy.orm.exc.DetachedInstanceError: Parent instance <WorkflowExecution at 0x7fcbd0a67940> is not bound to a Session; lazy load operation of attribute 'root_execution' cannot proceed (Background on this error at: http://sqlalche.me/e/bhk3)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/685899

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/train
Review: https://review.opendev.org/686349

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/685899
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=7a6aac0f5f008d67eeb5d3f63ddac42bb62f8e69
Submitter: Zuul
Branch: master

commit 7a6aac0f5f008d67eeb5d3f63ddac42bb62f8e69
Author: Renat Akhmerov <email address hidden>
Date: Thu Sep 26 17:48:40 2019 +0700

    Fix "root_execution" lazy loading issue and refactor execution.py

    * There's an issue with lazyly loaded field of WorkflowExecution
      model occuring on GET /v2/execution/<id> because the logic
      that calculates "published_global" of the execution rest resource
      hits "root_execution" field out of transaction scope indirectly
      within the "data_flow.get_workflow_environment_dict" method.
      This patch makes refactoring of this logic and calculates
      globally published variables of the workflow execution simply
      as its context that doesn't contain all internal data like
      "__execution" and "openstack".
    * Other style change.

    Closes-Bug: #1846152
    Change-Id: Ic8609e55930e2ed13653e79e8ca7a31c951d9030

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/686349
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=33d4a8bba35d79e8216d5babce48bbd04acfdfbd
Submitter: Zuul
Branch: stable/train

commit 33d4a8bba35d79e8216d5babce48bbd04acfdfbd
Author: Renat Akhmerov <email address hidden>
Date: Thu Sep 26 17:48:40 2019 +0700

    Fix "root_execution" lazy loading issue and refactor execution.py

    * There's an issue with lazyly loaded field of WorkflowExecution
      model occuring on GET /v2/execution/<id> because the logic
      that calculates "published_global" of the execution rest resource
      hits "root_execution" field out of transaction scope indirectly
      within the "data_flow.get_workflow_environment_dict" method.
      This patch makes refactoring of this logic and calculates
      globally published variables of the workflow execution simply
      as its context that doesn't contain all internal data like
      "__execution" and "openstack".
    * Other style change.

    Closes-Bug: #1846152
    Change-Id: Ic8609e55930e2ed13653e79e8ca7a31c951d9030

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/mistral 9.0.0.0rc2 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/mistral 10.0.0.0b1 development milestone.