def _execute_wfmodule_save(workflow: Workflow, wf_module: WfModule,
result: ProcessResult) -> OutputDelta:
"""
Call wf_module.cache_render_result() and build OutputDelta.
All this runs synchronously within a database lock. (It's a separate
function so that when we're done awaiting it, we can continue executing in
a context that doesn't use a database thread.)
Raise UnneededExecution if the WfModule has changed in the interim.
"""
# raises UnneededExecution
with locked_wf_module(workflow, wf_module) as safe_wf_module:
if safe_wf_module.notifications:
stale_crr = safe_wf_module.get_stale_cached_render_result()
if stale_crr is None:
stale_result = None
else:
# Read entire old Parquet file, blocking
stale_result = stale_crr.result
else:
stale_result = None
safe_wf_module.cache_render_result(
safe_wf_module.last_relevant_delta_id, result)
if safe_wf_module.notifications and result != stale_result:
safe_wf_module.has_unseen_notification = True
safe_wf_module.save(update_fields=["has_unseen_notification"])
return notifications.OutputDelta(safe_wf_module, stale_result,
result)
else:
return None # nothing to email
def _execute_wfmodule_save(wf_module: WfModule, result: ProcessResult,
old_result: ProcessResult) -> Tuple:
"""
Second database step of execute_wfmodule().
Writes result (and maybe has_unseen_notification) to the WfModule in the
database and returns a Tuple in this order:
* cached_render_result: the return value of execute_wfmodule().
* output_delta: if non-None, an OutputDelta to email to the Workflow
owner.
All this runs synchronously within a database lock. (It's a separate
function so that when we're done awaiting it, we can continue executing in
a context that doesn't use a database thread.)
Raises UnneededExecution if the WfModule has changed in the interim.
"""
with locked_wf_module(wf_module) as safe_wf_module:
if (safe_wf_module.last_relevant_delta_id !=
wf_module.last_relevant_delta_id):
raise UnneededExecution
cached_render_result = safe_wf_module.cache_render_result(
safe_wf_module.last_relevant_delta_id, result)
if safe_wf_module.notifications and result != old_result:
safe_wf_module.has_unseen_notification = True
output_delta = notifications.OutputDelta(safe_wf_module,
old_result, result)
else:
output_delta = None
# Save safe_wf_module, not wf_module, because we know we've only
# changed the cached_render_result columns. (We know because we
# locked the row before fetching it.) `wf_module.save()` might
# overwrite some newer values.
safe_wf_module.save()
return (cached_render_result, output_delta)