spiff-arena/SpiffWorkflow/bpmn/specs/events/event_definitions.py
Dan ba67d7ad34 Squashed 'SpiffWorkflow/' changes from 450ef3bcd..98c6294f1
98c6294f1 Merge pull request #287 from sartography/feature/workflow_data_exceptions
d40a1da59 Workflow Data Exceptions were broken in the previous error refactor.  This assures we are getting good messages from these errors.
a156378e1 Merge pull request #286 from sartography/feature/inclusive-gateway-support
7f6e398c2 bypass unnecessary checks in gateway joins
ade21a894 revert a few things
e1cf75202 Merge branch 'main' into feature/inclusive-gateway-support
15a0a4414 revert change to MultiChoice and handle no defaults in BPMN specs
e1469e6bb add support for diverging inclusive gateways
71fd86386 really prevent non-default flows without conditions
924759d9b clean up join specs
7378639d3 Merge pull request #284 from sartography/feature/improved-timer-events
dc8d139d2 remove useless method
530f23697 Merge branch 'main' into feature/improved-timer-events
307cca9c5 partially clean up existing gateways
0a344285e clean up task parsers
2cef997d1 add waiting_events method to bpmn workflow
48091c407 serializer migration script and miscellaneous fixes to serialization
61316854b store internal timer data as string/float
389c14c4c add some tests for parsing durations
582bc9482 convert timers to iso 8601
6dfd7ebe9 remove extraneous calls to update
6bd429529 clean up tests
d56e9912f remove useless method

git-subtree-dir: SpiffWorkflow
git-subtree-split: 98c6294f1240aee599cd98bcee58d121cb57b331
2023-01-26 18:17:35 -05:00

521 lines
20 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2012 Matthew Hampton
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
import re
from datetime import datetime, timedelta, timezone
from calendar import monthrange
from time import timezone as tzoffset
from copy import deepcopy
from SpiffWorkflow.task import TaskState
LOCALTZ = timezone(timedelta(seconds=-1 * tzoffset))
class EventDefinition(object):
"""
This is the base class for Event Definitions. It implements the default throw/catch
behavior for events.
If internal is true, this event should be thrown to the current workflow
If external is true, this event should be thrown to the outer workflow
Default throw behavior is to send the event based on the values of the internal
and external flags.
Default catch behavior is to set the event to fired
"""
def __init__(self):
# Ideally I'd mke these parameters, but I don't want to them to be parameters
# for any subclasses (as they are based on event type, not user choice) and
# I don't want to write a separate deserializer for every every type.
self.internal, self.external = True, True
@property
def event_type(self):
return f'{self.__class__.__module__}.{self.__class__.__name__}'
def has_fired(self, my_task):
return my_task._get_internal_data('event_fired', False)
def catch(self, my_task, event_definition=None):
my_task._set_internal_data(event_fired=True)
def throw(self, my_task):
self._throw(
event=my_task.task_spec.event_definition,
workflow=my_task.workflow,
outer_workflow=my_task.workflow.outer_workflow
)
def reset(self, my_task):
my_task._set_internal_data(event_fired=False)
def _throw(self, event, workflow, outer_workflow, correlations=None):
# This method exists because usually we just want to send the event in our
# own task spec, but we can't do that for message events.
# We also don't have a more sophisticated method for addressing events to
# a particular process, but this at least provides a mechanism for distinguishing
# between processes and subprocesses.
if self.external:
outer_workflow.catch(event, correlations)
if self.internal and (self.external and workflow != outer_workflow):
workflow.catch(event)
def __eq__(self, other):
return self.__class__.__name__ == other.__class__.__name__
class NamedEventDefinition(EventDefinition):
"""
Extend the base event class to provide a name for the event. Most throw/catch events
have names that names that will be used to identify the event.
:param name: the name of this event
"""
def __init__(self, name):
super(NamedEventDefinition, self).__init__()
self.name = name
def reset(self, my_task):
super(NamedEventDefinition, self).reset(my_task)
def __eq__(self, other):
return self.__class__.__name__ == other.__class__.__name__ and self.name == other.name
class CancelEventDefinition(EventDefinition):
"""
Cancel events are only handled by the outerworkflow, as they can only be used inside
of transaction subprocesses.
"""
def __init__(self):
super(CancelEventDefinition, self).__init__()
self.internal = False
@property
def event_type(self):
return 'Cancel'
class ErrorEventDefinition(NamedEventDefinition):
"""
Error events can occur only in subprocesses and as subprocess boundary events. They're
matched by code rather than name.
"""
def __init__(self, name, error_code=None):
super(ErrorEventDefinition, self).__init__(name)
self.error_code = error_code
self.internal = False
@property
def event_type(self):
return 'Error'
def __eq__(self, other):
return self.__class__.__name__ == other.__class__.__name__ and self.error_code in [ None, other.error_code ]
class EscalationEventDefinition(NamedEventDefinition):
"""
Escalation events have names, though they don't seem to be used for anything. Instead
the spec says that the escalation code should be matched.
"""
def __init__(self, name, escalation_code=None):
"""
Constructor.
:param escalation_code: The escalation code this event should
react to. If None then all escalations will activate this event.
"""
super(EscalationEventDefinition, self).__init__(name)
self.escalation_code = escalation_code
@property
def event_type(self):
return 'Escalation'
def __eq__(self, other):
return self.__class__.__name__ == other.__class__.__name__ and self.escalation_code in [ None, other.escalation_code ]
class CorrelationProperty:
"""Rules for generating a correlation key when a message is sent or received."""
def __init__(self, name, expression, correlation_keys):
self.name = name # This is the property name
self.expression = expression # This is how it's generated
self.correlation_keys = correlation_keys # These are the keys it's used by
class MessageEventDefinition(NamedEventDefinition):
"""The default message event."""
def __init__(self, name, correlation_properties=None):
super().__init__(name)
self.correlation_properties = correlation_properties or []
self.payload = None
self.internal = False
@property
def event_type(self):
return 'Message'
def catch(self, my_task, event_definition = None):
self.update_internal_data(my_task, event_definition)
super(MessageEventDefinition, self).catch(my_task, event_definition)
def throw(self, my_task):
# We can't update our own payload, because if this task is reached again
# we have to evaluate it again so we have to create a new event
event = MessageEventDefinition(self.name, self.correlation_properties)
# Generating a payload unfortunately needs to be handled using custom extensions
# However, there needs to be something to apply the correlations to in the
# standard case and this is line with the way Spiff works otherwise
event.payload = deepcopy(my_task.data)
correlations = self.get_correlations(my_task.workflow.script_engine, event.payload)
my_task.workflow.correlations.update(correlations)
self._throw(event, my_task.workflow, my_task.workflow.outer_workflow, correlations)
def update_internal_data(self, my_task, event_definition):
my_task.internal_data[event_definition.name] = event_definition.payload
def update_task_data(self, my_task):
# I've added this method so that different message implementations can handle
# copying their message data into the task
payload = my_task.internal_data.get(self.name)
if payload is not None:
my_task.set_data(**payload)
def get_correlations(self, script_engine, payload):
correlations = {}
for property in self.correlation_properties:
for key in property.correlation_keys:
if key not in correlations:
correlations[key] = {}
correlations[key][property.name] = script_engine._evaluate(property.expression, payload)
return correlations
class NoneEventDefinition(EventDefinition):
"""
This class defines behavior for NoneEvents. We override throw to do nothing.
"""
def __init__(self):
self.internal, self.external = False, False
@property
def event_type(self):
return 'Default'
def throw(self, my_task):
"""It's a 'none' event, so nothing to throw."""
pass
def reset(self, my_task):
"""It's a 'none' event, so nothing to reset."""
pass
class SignalEventDefinition(NamedEventDefinition):
"""The SignalEventDefinition is the implementation of event definition used for Signal Events."""
@property
def spec_type(self):
return 'Signal'
class TerminateEventDefinition(EventDefinition):
"""The TerminateEventDefinition is the implementation of event definition used for Termination Events."""
def __init__(self):
super(TerminateEventDefinition, self).__init__()
self.external = False
@property
def event_type(self):
return 'Terminate'
class TimerEventDefinition(EventDefinition):
def __init__(self, name, expression):
"""
Constructor.
:param name: The description of the timer.
:param expression: An ISO 8601 datetime or interval expression.
"""
super().__init__()
self.name = name
self.expression = expression
@staticmethod
def get_datetime(expression):
dt = datetime.fromisoformat(expression)
if dt.tzinfo is None:
dt = datetime.combine(dt.date(), dt.time(), LOCALTZ)
return dt.astimezone(timezone.utc)
@staticmethod
def get_timedelta_from_start(parsed_duration, start=None):
start = start or datetime.now(timezone.utc)
years, months, days = parsed_duration.pop('years', 0), parsed_duration.pop('months', 0), parsed_duration.pop('days', 0)
months += years * 12
for idx in range(int(months)):
year, month = start.year + idx // 12, start.month + idx % 12
days += monthrange(year, month)[1]
year, month = start.year + months // 12, start.month + months % 12
days += (months - int(months)) * monthrange(year, month)[1]
parsed_duration['days'] = days
return timedelta(**parsed_duration)
@staticmethod
def get_timedelta_from_end(parsed_duration, end):
years, months, days = parsed_duration.pop('years', 0), parsed_duration.pop('months', 0), parsed_duration.pop('days', 0)
months += years * 12
for idx in range(1, int(months) + 1):
year = end.year - (1 + (idx - end.month) // 12)
month = 1 + (end.month - idx - 1) % 12
days += monthrange(year, month)[1]
days += (months - int(months)) * monthrange(
end.year - (1 + (int(months)- end.month) // 12),
1 + (end.month - months - 1) % 12)[1]
parsed_duration['days'] = days
return timedelta(**parsed_duration)
@staticmethod
def parse_iso_duration(expression):
# Based on https://en.wikipedia.org/wiki/ISO_8601#Time_intervals
parsed, expr_t, current = {}, False, expression.lower().strip('p').replace(',', '.')
for designator in ['years', 'months', 'weeks', 'days', 't', 'hours', 'minutes', 'seconds']:
value = current.split(designator[0], 1)
if len(value) == 2:
duration, remainder = value
if duration.isdigit():
parsed[designator] = int(duration)
elif duration.replace('.', '').isdigit() and not remainder:
parsed[designator] = float(duration)
if designator in parsed or designator == 't':
current = remainder
if designator == 't':
expr_t = True
date_specs, time_specs = ['years', 'months', 'days'], ['hours', 'minutes', 'seconds']
parsed_t = len([d for d in parsed if d in time_specs]) > 0
if len(current) or parsed_t != expr_t or ('weeks' in parsed and any(v for v in parsed if v in date_specs)):
raise Exception('Invalid duration')
# The actual timedelta will have to be computed based on a start or end date, to account for
# months lengths, leap days, etc. This returns a dict of the parsed elements
return parsed
@staticmethod
def parse_iso_week(expression):
# https://en.wikipedia.org/wiki/ISO_8601#Week_dates
m = re.match('(\d{4})W(\d{2})(\d)(T.+)?', expression.upper().replace('-', ''))
year, month, day, ts = m.groups()
ds = datetime.fromisocalendar(int(year), int(month), int(day)).strftime('%Y-%m-%d')
return TimerEventDefinition.get_datetime(ds + (ts or ''))
@staticmethod
def parse_time_or_duration(expression):
if expression.upper().startswith('P'):
return TimerEventDefinition.parse_iso_duration(expression)
elif 'W' in expression.upper():
return TimerEventDefinition.parse_iso_week(expression)
else:
return TimerEventDefinition.get_datetime(expression)
@staticmethod
def parse_iso_recurring_interval(expression):
components = expression.upper().replace('--', '/').strip('R').split('/')
cycles = int(components[0]) if components[0] else -1
start_or_duration = TimerEventDefinition.parse_time_or_duration(components[1])
if len(components) == 3:
end_or_duration = TimerEventDefinition.parse_time_or_duration(components[2])
else:
end_or_duration = None
if isinstance(start_or_duration, datetime):
# Start time + interval duration
start = start_or_duration
duration = TimerEventDefinition.get_timedelta_from_start(end_or_duration, start_or_duration)
elif isinstance(end_or_duration, datetime):
# End time + interval duration
duration = TimerEventDefinition.get_timedelta_from_end(start_or_duration, end_or_duration)
start = end_or_duration - duration
elif end_or_duration is None:
# Just an interval duration, assume a start time of now
start = datetime.now(timezone.utc)
duration = TimeDateEventDefinition.get_timedelta_from_start(start_or_duration, start)
else:
raise Exception("Invalid recurring interval")
return cycles, start, duration
def __eq__(self, other):
return self.__class__.__name__ == other.__class__.__name__ and self.name == other.name
class TimeDateEventDefinition(TimerEventDefinition):
"""A Timer event represented by a specific date/time."""
@property
def event_type(self):
return 'Time Date Timer'
def has_fired(self, my_task):
event_value = my_task._get_internal_data('event_value')
if event_value is None:
event_value = my_task.workflow.script_engine.evaluate(my_task, self.expression)
my_task._set_internal_data(event_value=event_value)
if TimerEventDefinition.parse_time_or_duration(event_value) < datetime.now(timezone.utc):
my_task._set_internal_data(event_fired=True)
return my_task._get_internal_data('event_fired', False)
def timer_value(self, my_task):
return my_task._get_internal_data('event_value')
class DurationTimerEventDefinition(TimerEventDefinition):
"""A timer event represented by a duration"""
@property
def event_type(self):
return 'Duration Timer'
def has_fired(self, my_task):
event_value = my_task._get_internal_data("event_value")
if event_value is None:
expression = my_task.workflow.script_engine.evaluate(my_task, self.expression)
parsed_duration = TimerEventDefinition.parse_iso_duration(expression)
event_value = (datetime.now(timezone.utc) + TimerEventDefinition.get_timedelta_from_start(parsed_duration)).isoformat()
my_task._set_internal_data(event_value=event_value)
if TimerEventDefinition.get_datetime(event_value) < datetime.now(timezone.utc):
my_task._set_internal_data(event_fired=True)
return my_task._get_internal_data('event_fired', False)
def timer_value(self, my_task):
return my_task._get_internal_data("event_value")
class CycleTimerEventDefinition(TimerEventDefinition):
@property
def event_type(self):
return 'Cycle Timer'
def has_fired(self, my_task):
if not my_task._get_internal_data('event_fired'):
# Only check for the next cycle when the event has not fired to prevent cycles from being skipped.
event_value = my_task._get_internal_data('event_value')
if event_value is None:
expression = my_task.workflow.script_engine.evaluate(my_task, self.expression)
cycles, start, duration = TimerEventDefinition.parse_iso_recurring_interval(expression)
event_value = {'cycles': cycles, 'next': start.isoformat(), 'duration': duration.total_seconds()}
if event_value['cycles'] > 0:
next_event = datetime.fromisoformat(event_value['next'])
if next_event < datetime.now(timezone.utc):
my_task._set_internal_data(event_fired=True)
event_value['next'] = (next_event + timedelta(seconds=event_value['duration'])).isoformat()
my_task._set_internal_data(event_value=event_value)
return my_task._get_internal_data('event_fired', False)
def timer_value(self, my_task):
event_value = my_task._get_internal_data('event_value')
if event_value is not None and event_value['cycles'] > 0:
return event_value['next']
def complete(self, my_task):
event_value = my_task._get_internal_data('event_value')
if event_value is not None and event_value['cycles'] == 0:
my_task.internal_data.pop('event_value')
return True
def complete_cycle(self, my_task):
# Only increment when the task completes
if my_task._get_internal_data('event_value') is not None:
my_task.internal_data['event_value']['cycles'] -= 1
class MultipleEventDefinition(EventDefinition):
def __init__(self, event_definitions=None, parallel=False):
super().__init__()
self.event_definitions = event_definitions or []
self.parallel = parallel
@property
def event_type(self):
return 'Multiple'
def has_fired(self, my_task):
seen_events = my_task.internal_data.get('seen_events', [])
for event in self.event_definitions:
if isinstance(event, (TimerEventDefinition, CycleTimerEventDefinition)):
child = [c for c in my_task.children if c.task_spec.event_definition == event]
child[0].task_spec._update_hook(child[0])
child[0]._set_state(TaskState.MAYBE)
if event.has_fired(my_task):
seen_events.append(event)
if self.parallel:
# Parallel multiple need to match all events
return all(event in seen_events for event in self.event_definitions)
else:
return len(seen_events) > 0
def catch(self, my_task, event_definition=None):
event_definition.catch(my_task, event_definition)
seen_events = my_task.internal_data.get('seen_events', []) + [event_definition]
my_task._set_internal_data(seen_events=seen_events)
def reset(self, my_task):
my_task.internal_data.pop('seen_events', None)
super().reset(my_task)
def __eq__(self, other):
# This event can catch any of the events associated with it
for event in self.event_definitions:
if event == other:
return True
return False
def throw(self, my_task):
# Mutiple events throw all associated events when they fire
for event_definition in self.event_definitions:
self._throw(
event=event_definition,
workflow=my_task.workflow,
outer_workflow=my_task.workflow.outer_workflow
)