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HasStates: fix status code inheritance

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use mro for status code inheritance
- as a consequence, the decorator class 'StatusCode' is now a
  decorator function 'status_code'. snake case is anyway more
  common for decorators.
- adapt tests
+ fix an error message

Change-Id: Ib409b963c51e0fe807397ff1d73d77d0147b8580
This commit is contained in:
zolliker
2023-01-25 08:34:37 +01:00
parent dcd79506a9
commit a4ebcb9bb7
3 changed files with 124 additions and 74 deletions
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166
frappy/states.py
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@@ -26,44 +26,38 @@ handles status depending on statemachine state
"""
from frappy.core import BUSY, IDLE, ERROR, Parameter, Command
from frappy.errors import ProgrammingError
from frappy.core import BUSY, IDLE, ERROR, Parameter, Command, Done
from frappy.lib.statemachine import StateMachine, Finish, Start, Stop, \
Retry # pylint: disable=unused-import
class StatusCode:
"""decorator for state methods
def status_code(code, text=None):
"""decorator, attaching a status to a state function
:param code: the code assigned to the state function
:param text: the text assigned to the state function
if not given, the text is taken from the state functions name
:param code: the first element of the secop status tuple
:param text: the second element of the secop status tuple. if not given,
the name of the state function is used (underscores replaced by spaces)
:return: the decorator function
if a state function has no attached status and is a method of the module running
the state machine, the status is inherited from an overridden method, if available
a state function without attached status does not change the status, or, if it is
used as the start function, BUSY is taken as default status code
"""
def __init__(self, code, text=None):
self.code = code
self.text = text
def __set_name__(self, owner, name):
if not issubclass(owner, HasStates):
raise ProgrammingError('when using decorator "status_code", %s must inherit HasStates' % owner.__name__)
self.cls = owner
self.name = name
if 'statusMap' not in owner.__dict__:
# we need a copy on each inheritance level
owner.statusMap = owner.statusMap.copy()
owner.statusMap[name] = self.code, name.replace('_', ' ') if self.text is None else self.text
setattr(owner, name, self.func) # replace with original method
def __call__(self, func):
self.func = func
return self
def wrapper(func):
func.status = code, func.__name__.replace('_', ' ') if text is None else text
return func
return wrapper
class HasStates:
"""mixin for modules needing a statemachine"""
status = Parameter() # make sure this is a parameter
all_status_changes = True # when True, send also updates for status changes within a cycle
_state_machine = None
statusMap = {} # a dict populated with status values for methods used as state functions
_status = IDLE, ''
statusMap = None # cache for status values derived from state methods
def init_state_machine(self, **kwds):
"""initialize the state machine
@@ -77,34 +71,32 @@ class HasStates:
idle_status=(IDLE, ''),
transition=self.state_transition,
reset_fast_poll=False,
status_text='',
status=(IDLE, ''),
**kwds)
def initModule(self):
super().initModule()
self.statusMap = {}
self.init_state_machine()
def state_transition(self, sm, newstate):
"""handle status updates"""
status = self.get_status(newstate)
if status is not None:
# if a status_code is given, remember the text of this state
sm.status_text = status[1]
if isinstance(sm.next_task, Stop):
if newstate:
status = self.status[0], 'stopping (%s)' % sm.status_text
elif isinstance(sm.next_task, Start):
next_status = self.get_status(sm.next_task.newstate, BUSY)
if newstate:
if sm.next_task:
if isinstance(sm.next_task, Stop):
if newstate and status is not None:
status = status[0], 'stopping (%s)' % status[1]
elif newstate:
# restart case
status = next_status[0], 'restarting (%s)' % sm.status_text
if status is not None:
status = sm.status[0], 'restarting (%s)' % status[1]
else:
# start case
status = next_status
if status is None:
return # no status_code given -> no change
if status != self.status:
self.status = status
status = self.get_status(sm.next_task.newstate, BUSY)
if status:
sm.status = status
if self.all_status_changes:
self.read_status()
def get_status(self, statefunc, default_code=None):
"""get the status assigned to a statefunc
@@ -119,21 +111,82 @@ class HasStates:
status = self._state_machine.idle_status or (ERROR, 'Finish was returned without final status')
else:
name = statefunc.__name__
status = self.statusMap.get(name)
try:
# look up in statusMap cache
status = self.statusMap[name]
except KeyError:
# try to get status from method or inherited method
cls = type(self)
for base in cls.__mro__:
try:
status = getattr(base, name, None).status
break
except AttributeError:
pass
else:
status = None
# store it in the cache for all further calls
self.statusMap[name] = status
if status is None and default_code is not None:
status = default_code, name.replace('_', ' ')
print('get_status', statefunc, status, default_code)
return status
def read_status(self):
sm = self._state_machine
if sm.status == self.status:
return Done
return sm.status
def cycle_machine(self):
sm = self._state_machine
sm.cycle()
if sm.statefunc is None:
if sm.reset_fast_poll:
sm.reset_fast_poll = False
self.setFastPoll(False)
self.read_status()
def doPoll(self):
super().doPoll()
sm = self._state_machine
sm.cycle()
if sm.statefunc is None and sm.reset_fast_poll:
sm.reset_fast_poll = False
self.setFastPoll(False)
self.cycle_machine()
def start_machine(self, statefunc, fast_poll=True, cleanup=None, **kwds):
def on_cleanup(self, sm):
"""general cleanup method
override and super call for code to be executed for
any cleanup case
"""
if isinstance(sm.cleanup_reason, Exception):
return self.on_error(sm)
if isinstance(sm.cleanup_reason, Start):
return self.on_restart(sm)
if isinstance(sm.cleanup_reason, Stop):
return self.on_stop(sm)
self.log.error('bad cleanup reason %r', sm.cleanup_reason)
return None
def on_error(self, sm):
"""cleanup on error
override and probably super call for code to be executed in
case of error
"""
self.log.error('handle error %r', sm.cleanup_reason)
self.final_status(ERROR, repr(sm.cleanup_reason))
def on_restart(self, sm):
"""cleanup on restart
override for code to be executed before a restart
"""
def on_stop(self, sm):
"""cleanup on stop
override for code to be executed after stopping
"""
def start_machine(self, statefunc, fast_poll=True, **kwds):
"""start or restart the state machine
:param statefunc: the initial state to be called
@@ -152,12 +205,11 @@ class HasStates:
4) the state machine continues at the given statefunc
"""
sm = self._state_machine
status = self.get_status(statefunc, BUSY)
sm.status = self.get_status(statefunc, BUSY)
if sm.statefunc:
status = status[0], 'restarting'
self.status = status
sm.status_text = status[1]
sm.start(statefunc, cleanup=cleanup, **kwds)
sm.status = sm.status[0], 'restarting'
sm.start(statefunc, cleanup=kwds.pop('cleanup', self.on_cleanup), **kwds)
self.read_status()
if fast_poll:
sm.reset_fast_poll = True
self.setFastPoll(True)
@@ -178,7 +230,8 @@ class HasStates:
if sm.is_active:
sm.idle_status = stopped_status
sm.stop()
self.status = self.status[0], 'stopping'
sm.status = self.get_status(sm.statefunc, sm.status[0])[0], 'stopping'
self.read_status()
self.pollInfo.trigger(True) # trigger poller
@Command
@@ -194,4 +247,5 @@ class HasStates:
"""
sm = self._state_machine
sm.idle_status = code, text
sm.cleanup = None
return Finish