# copyright 2003-2012 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
#
# This file is part of CubicWeb.
#
# CubicWeb 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.
#
# CubicWeb 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 CubicWeb. If not, see <http://www.gnu.org/licenses/>.
"""workflow handling:
* entity types defining workflow (Workflow, State, Transition...)
* workflow history (TrInfo)
* adapter for workflowable entities (IWorkflowableAdapter)
"""
from __future__ import print_function
__docformat__ = "restructuredtext en"
from six import text_type, string_types
from logilab.common.decorators import cached, clear_cache
from logilab.common.deprecation import deprecated
from cubicweb.entities import AnyEntity, fetch_config
from cubicweb.view import EntityAdapter
from cubicweb.predicates import relation_possible
try:
from cubicweb import server
except ImportError:
# We need to lookup DEBUG from there,
# however a pure dbapi client may not have it.
class server(object): pass
server.DEBUG = False
class WorkflowException(Exception): pass
class Workflow(AnyEntity):
__regid__ = 'Workflow'
@property
def initial(self):
"""return the initial state for this workflow"""
return self.initial_state and self.initial_state[0] or None
def is_default_workflow_of(self, etype):
"""return True if this workflow is the default workflow for the given
entity type
"""
return any(et for et in self.reverse_default_workflow
if et.name == etype)
def iter_workflows(self, _done=None):
"""return an iterator on actual workflows, eg this workflow and its
subworkflows
"""
# infinite loop safety belt
if _done is None:
_done = set()
yield self
_done.add(self.eid)
for tr in self._cw.execute('Any T WHERE T is WorkflowTransition, '
'T transition_of WF, WF eid %(wf)s',
{'wf': self.eid}).entities():
if tr.subwf.eid in _done:
continue
for subwf in tr.subwf.iter_workflows(_done):
yield subwf
# state / transitions accessors ############################################
def state_by_name(self, statename):
rset = self._cw.execute('Any S, SN WHERE S name SN, S name %(n)s, '
'S state_of WF, WF eid %(wf)s',
{'n': statename, 'wf': self.eid})
if rset:
return rset.get_entity(0, 0)
return None
def state_by_eid(self, eid):
rset = self._cw.execute('Any S, SN WHERE S name SN, S eid %(s)s, '
'S state_of WF, WF eid %(wf)s',
{'s': eid, 'wf': self.eid})
if rset:
return rset.get_entity(0, 0)
return None
def transition_by_name(self, trname):
rset = self._cw.execute('Any T, TN WHERE T name TN, T name %(n)s, '
'T transition_of WF, WF eid %(wf)s',
{'n': text_type(trname), 'wf': self.eid})
if rset:
return rset.get_entity(0, 0)
return None
def transition_by_eid(self, eid):
rset = self._cw.execute('Any T, TN WHERE T name TN, T eid %(t)s, '
'T transition_of WF, WF eid %(wf)s',
{'t': eid, 'wf': self.eid})
if rset:
return rset.get_entity(0, 0)
return None
# wf construction methods ##################################################
def add_state(self, name, initial=False, **kwargs):
"""add a state to this workflow"""
state = self._cw.create_entity('State', name=text_type(name), **kwargs)
self._cw.execute('SET S state_of WF WHERE S eid %(s)s, WF eid %(wf)s',
{'s': state.eid, 'wf': self.eid})
if initial:
assert not self.initial, "Initial state already defined as %s" % self.initial
self._cw.execute('SET WF initial_state S '
'WHERE S eid %(s)s, WF eid %(wf)s',
{'s': state.eid, 'wf': self.eid})
return state
def _add_transition(self, trtype, name, fromstates,
requiredgroups=(), conditions=(), **kwargs):
tr = self._cw.create_entity(trtype, name=text_type(name), **kwargs)
self._cw.execute('SET T transition_of WF '
'WHERE T eid %(t)s, WF eid %(wf)s',
{'t': tr.eid, 'wf': self.eid})
assert fromstates, fromstates
if not isinstance(fromstates, (tuple, list)):
fromstates = (fromstates,)
for state in fromstates:
if hasattr(state, 'eid'):
state = state.eid
self._cw.execute('SET S allowed_transition T '
'WHERE S eid %(s)s, T eid %(t)s',
{'s': state, 't': tr.eid})
tr.set_permissions(requiredgroups, conditions, reset=False)
return tr
def add_transition(self, name, fromstates, tostate=None,
requiredgroups=(), conditions=(), **kwargs):
"""add a transition to this workflow from some state(s) to another"""
tr = self._add_transition('Transition', name, fromstates,
requiredgroups, conditions, **kwargs)
if tostate is not None:
if hasattr(tostate, 'eid'):
tostate = tostate.eid
self._cw.execute('SET T destination_state S '
'WHERE S eid %(s)s, T eid %(t)s',
{'t': tr.eid, 's': tostate})
return tr
def add_wftransition(self, name, subworkflow, fromstates, exitpoints=(),
requiredgroups=(), conditions=(), **kwargs):
"""add a workflow transition to this workflow"""
tr = self._add_transition('WorkflowTransition', name, fromstates,
requiredgroups, conditions, **kwargs)
if hasattr(subworkflow, 'eid'):
subworkflow = subworkflow.eid
assert self._cw.execute('SET T subworkflow WF WHERE WF eid %(wf)s,T eid %(t)s',
{'t': tr.eid, 'wf': subworkflow})
for fromstate, tostate in exitpoints:
tr.add_exit_point(fromstate, tostate)
return tr
def replace_state(self, todelstate, replacement):
"""migration convenience method"""
if not hasattr(todelstate, 'eid'):
todelstate = self.state_by_name(todelstate)
if not hasattr(replacement, 'eid'):
replacement = self.state_by_name(replacement)
args = {'os': todelstate.eid, 'ns': replacement.eid}
execute = self._cw.execute
execute('SET X in_state NS WHERE X in_state OS, '
'NS eid %(ns)s, OS eid %(os)s', args)
execute('SET X from_state NS WHERE X from_state OS, '
'OS eid %(os)s, NS eid %(ns)s', args)
execute('SET X to_state NS WHERE X to_state OS, '
'OS eid %(os)s, NS eid %(ns)s', args)
todelstate.cw_delete()
class BaseTransition(AnyEntity):
"""customized class for abstract transition
provides a specific may_be_fired method to check if the relation may be
fired by the logged user
"""
__regid__ = 'BaseTransition'
fetch_attrs, cw_fetch_order = fetch_config(['name', 'type'])
def __init__(self, *args, **kwargs):
if self.cw_etype == 'BaseTransition':
raise WorkflowException('should not be instantiated')
super(BaseTransition, self).__init__(*args, **kwargs)
@property
def workflow(self):
return self.transition_of[0]
def has_input_state(self, state):
if hasattr(state, 'eid'):
state = state.eid
return any(s for s in self.reverse_allowed_transition if s.eid == state)
def may_be_fired(self, eid):
"""return true if the logged user may fire this transition
`eid` is the eid of the object on which we may fire the transition
"""
DBG = False
if server.DEBUG & server.DBG_SEC:
if 'transition' in server._SECURITY_CAPS:
DBG = True
user = self._cw.user
# check user is at least in one of the required groups if any
groups = frozenset(g.name for g in self.require_group)
if groups:
matches = user.matching_groups(groups)
if matches:
if DBG:
print('may_be_fired: %r may fire: user matches %s' % (self.name, groups))
return matches
if 'owners' in groups and user.owns(eid):
if DBG:
print('may_be_fired: %r may fire: user is owner' % self.name)
return True
# check one of the rql expression conditions matches if any
if self.condition:
if DBG:
print('my_be_fired: %r: %s' %
(self.name, [(rqlexpr.expression,
rqlexpr.check_expression(self._cw, eid))
for rqlexpr in self.condition]))
for rqlexpr in self.condition:
if rqlexpr.check_expression(self._cw, eid):
return True
if self.condition or groups:
return False
return True
def set_permissions(self, requiredgroups=(), conditions=(), reset=True):
"""set or add (if `reset` is False) groups and conditions for this
transition
"""
if reset:
self._cw.execute('DELETE T require_group G WHERE T eid %(x)s',
{'x': self.eid})
self._cw.execute('DELETE T condition R WHERE T eid %(x)s',
{'x': self.eid})
for gname in requiredgroups:
rset = self._cw.execute('SET T require_group G '
'WHERE T eid %(x)s, G name %(gn)s',
{'x': self.eid, 'gn': text_type(gname)})
assert rset, '%s is not a known group' % gname
if isinstance(conditions, string_types):
conditions = (conditions,)
for expr in conditions:
if isinstance(expr, string_types):
kwargs = {'expr': text_type(expr)}
else:
assert isinstance(expr, dict)
kwargs = expr
kwargs['x'] = self.eid
kwargs.setdefault('mainvars', u'X')
self._cw.execute('INSERT RQLExpression X: X exprtype "ERQLExpression", '
'X expression %(expr)s, X mainvars %(mainvars)s, '
'T condition X WHERE T eid %(x)s', kwargs)
# XXX clear caches?
class Transition(BaseTransition):
"""customized class for Transition entities"""
__regid__ = 'Transition'
def dc_long_title(self):
return '%s (%s)' % (self.name, self._cw._(self.name))
def destination(self, entity):
try:
return self.destination_state[0]
except IndexError:
return entity.cw_adapt_to('IWorkflowable').latest_trinfo().previous_state
def potential_destinations(self):
try:
yield self.destination_state[0]
except IndexError:
for incomingstate in self.reverse_allowed_transition:
for tr in incomingstate.reverse_destination_state:
for previousstate in tr.reverse_allowed_transition:
yield previousstate
class WorkflowTransition(BaseTransition):
"""customized class for WorkflowTransition entities"""
__regid__ = 'WorkflowTransition'
@property
def subwf(self):
return self.subworkflow[0]
def destination(self, entity):
return self.subwf.initial
def potential_destinations(self):
yield self.subwf.initial
def add_exit_point(self, fromstate, tostate):
if hasattr(fromstate, 'eid'):
fromstate = fromstate.eid
if tostate is None:
self._cw.execute('INSERT SubWorkflowExitPoint X: T subworkflow_exit X, '
'X subworkflow_state FS WHERE T eid %(t)s, FS eid %(fs)s',
{'t': self.eid, 'fs': fromstate})
else:
if hasattr(tostate, 'eid'):
tostate = tostate.eid
self._cw.execute('INSERT SubWorkflowExitPoint X: T subworkflow_exit X, '
'X subworkflow_state FS, X destination_state TS '
'WHERE T eid %(t)s, FS eid %(fs)s, TS eid %(ts)s',
{'t': self.eid, 'fs': fromstate, 'ts': tostate})
def get_exit_point(self, entity, stateeid):
"""if state is an exit point, return its associated destination state"""
if hasattr(stateeid, 'eid'):
stateeid = stateeid.eid
try:
tostateeid = self.exit_points()[stateeid]
except KeyError:
return None
if tostateeid is None:
# go back to state from which we've entered the subworkflow
return entity.cw_adapt_to('IWorkflowable').subworkflow_input_trinfo().previous_state
return self._cw.entity_from_eid(tostateeid)
@cached
def exit_points(self):
result = {}
for ep in self.subworkflow_exit:
result[ep.subwf_state.eid] = ep.destination and ep.destination.eid
return result
def cw_clear_all_caches(self):
super(WorkflowTransition, self).cw_clear_all_caches()
clear_cache(self, 'exit_points')
class SubWorkflowExitPoint(AnyEntity):
"""customized class for SubWorkflowExitPoint entities"""
__regid__ = 'SubWorkflowExitPoint'
@property
def subwf_state(self):
return self.subworkflow_state[0]
@property
def destination(self):
return self.destination_state and self.destination_state[0] or None
class State(AnyEntity):
"""customized class for State entities"""
__regid__ = 'State'
fetch_attrs, cw_fetch_order = fetch_config(['name'])
rest_attr = 'eid'
def dc_long_title(self):
return '%s (%s)' % (self.name, self._cw._(self.name))
@property
def workflow(self):
# take care, may be missing in multi-sources configuration
return self.state_of and self.state_of[0] or None
class TrInfo(AnyEntity):
"""customized class for Transition information entities
"""
__regid__ = 'TrInfo'
fetch_attrs, cw_fetch_order = fetch_config(['creation_date', 'comment'],
pclass=None) # don't want modification_date
@property
def for_entity(self):
return self.wf_info_for[0]
@property
def previous_state(self):
return self.from_state[0]
@property
def new_state(self):
return self.to_state[0]
@property
def transition(self):
return self.by_transition and self.by_transition[0] or None
class IWorkflowableAdapter(EntityAdapter):
"""base adapter providing workflow helper methods for workflowable entities.
"""
__regid__ = 'IWorkflowable'
__select__ = relation_possible('in_state')
@cached
def cwetype_workflow(self):
"""return the default workflow for entities of this type"""
# XXX CWEType method
wfrset = self._cw.execute('Any WF WHERE ET default_workflow WF, '
'ET name %(et)s', {'et': text_type(self.entity.cw_etype)})
if wfrset:
return wfrset.get_entity(0, 0)
self.warning("can't find any workflow for %s", self.entity.cw_etype)
return None
@property
def main_workflow(self):
"""return current workflow applied to this entity"""
if self.entity.custom_workflow:
return self.entity.custom_workflow[0]
return self.cwetype_workflow()
@property
def current_workflow(self):
"""return current workflow applied to this entity"""
return self.current_state and self.current_state.workflow or self.main_workflow
@property
def current_state(self):
"""return current state entity"""
return self.entity.in_state and self.entity.in_state[0] or None
@property
def state(self):
"""return current state name"""
try:
return self.current_state.name
except AttributeError:
self.warning('entity %s has no state', self.entity)
return None
@property
def printable_state(self):
"""return current state name translated to context's language"""
state = self.current_state
if state:
return self._cw._(state.name)
return u''
@property
def workflow_history(self):
"""return the workflow history for this entity (eg ordered list of
TrInfo entities)
"""
return self.entity.reverse_wf_info_for
def latest_trinfo(self):
"""return the latest transition information for this entity"""
try:
return self.workflow_history[-1]
except IndexError:
return None
def possible_transitions(self, type='normal'):
"""generates transition that MAY be fired for the given entity,
expected to be in this state
used only by the UI
"""
if self.current_state is None or self.current_workflow is None:
return
rset = self._cw.execute(
'Any T,TT, TN WHERE S allowed_transition T, S eid %(x)s, '
'T type TT, T type %(type)s, '
'T name TN, T transition_of WF, WF eid %(wfeid)s',
{'x': self.current_state.eid, 'type': text_type(type),
'wfeid': self.current_workflow.eid})
for tr in rset.entities():
if tr.may_be_fired(self.entity.eid):
yield tr
def subworkflow_input_trinfo(self):
"""return the TrInfo which has be recorded when this entity went into
the current sub-workflow
"""
if self.main_workflow.eid == self.current_workflow.eid:
return # doesn't make sense
subwfentries = []
for trinfo in self.workflow_history:
if (trinfo.transition and
trinfo.previous_state.workflow.eid != trinfo.new_state.workflow.eid):
# entering or leaving a subworkflow
if (subwfentries and
subwfentries[-1].new_state.workflow.eid == trinfo.previous_state.workflow.eid and
subwfentries[-1].previous_state.workflow.eid == trinfo.new_state.workflow.eid):
# leave
del subwfentries[-1]
else:
# enter
subwfentries.append(trinfo)
if not subwfentries:
return None
return subwfentries[-1]
def subworkflow_input_transition(self):
"""return the transition which has went through the current sub-workflow
"""
return getattr(self.subworkflow_input_trinfo(), 'transition', None)
def _add_trinfo(self, comment, commentformat, treid=None, tseid=None):
kwargs = {}
if comment is not None:
kwargs['comment'] = comment
if commentformat is not None:
kwargs['comment_format'] = commentformat
kwargs['wf_info_for'] = self.entity
if treid is not None:
kwargs['by_transition'] = self._cw.entity_from_eid(treid)
if tseid is not None:
kwargs['to_state'] = self._cw.entity_from_eid(tseid)
return self._cw.create_entity('TrInfo', **kwargs)
def _get_transition(self, tr):
assert self.current_workflow
if isinstance(tr, string_types):
_tr = self.current_workflow.transition_by_name(tr)
assert _tr is not None, 'not a %s transition: %s' % (
self.__regid__, tr)
tr = _tr
return tr
def fire_transition(self, tr, comment=None, commentformat=None):
"""change the entity's state by firing given transition (name or entity)
in entity's workflow
"""
tr = self._get_transition(tr)
return self._add_trinfo(comment, commentformat, tr.eid)
def fire_transition_if_possible(self, tr, comment=None, commentformat=None):
"""change the entity's state by firing given transition (name or entity)
in entity's workflow if this transition is possible
"""
tr = self._get_transition(tr)
if any(tr_ for tr_ in self.possible_transitions()
if tr_.eid == tr.eid):
self.fire_transition(tr)
def change_state(self, statename, comment=None, commentformat=None, tr=None):
"""change the entity's state to the given state (name or entity) in
entity's workflow. This method should only by used by manager to fix an
entity's state when their is no matching transition, otherwise
fire_transition should be used.
"""
assert self.current_workflow
if hasattr(statename, 'eid'):
stateeid = statename.eid
else:
state = self.current_workflow.state_by_name(statename)
if state is None:
raise WorkflowException('not a %s state: %s' % (self.__regid__,
statename))
stateeid = state.eid
# XXX try to find matching transition?
return self._add_trinfo(comment, commentformat, tr and tr.eid, stateeid)
def set_initial_state(self, statename):
"""set a newly created entity's state to the given state (name or entity)
in entity's workflow. This is useful if you don't want it to be the
workflow's initial state.
"""
assert self.current_workflow
if hasattr(statename, 'eid'):
stateeid = statename.eid
else:
state = self.current_workflow.state_by_name(statename)
if state is None:
raise WorkflowException('not a %s state: %s' % (self.__regid__,
statename))
stateeid = state.eid
self._cw.execute('SET X in_state S WHERE X eid %(x)s, S eid %(s)s',
{'x': self.entity.eid, 's': stateeid})