1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268
|
#!/usr/bin/env python3.2
#
# Copyright (c) Net24 Limited, Christchurch, New Zealand 2011-2012
# and Voyager Internet Ltd, New Zealand, 2012-2013
#
# This file is part of py-magcode-core.
#
# Py-magcode-core is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published
# by the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Py-magcode-core 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with py-magcode-core. If not, see <http://www.gnu.org/licenses/>.
#
import threading
import os
import sys
from functools import wraps
from sqlalchemy.orm.exc import NoResultFound
from sqlalchemy import text
from magcode.core.logging import *
from magcode.core.globals_ import *
from magcode.core.database.event import Event
from magcode.core.database.event import SyncEvent
from magcode.core.database.event import ESTATE_SUCCESS
from magcode.core.database.event import ESTATE_RETRY
from magcode.core.database.event import ESTATE_FAILURE
from magcode.core.database.event import ESTATE_NEW
from magcode.core.database.utility import *
def sync():
"""Decorator - Places self._lock around method"""
def _sync(func):
@wraps(func)
def _syncs(self, *args, **kwargs):
lock = self.__getattribute__('_lock')
lock.acquire()
try:
return func(self, *args, **kwargs)
finally:
lock.release()
return _syncs
return _sync
class StateMachineError(Exception):
"""
Base class for all State Machine Error Exceptions
"""
def __init__(self, *args):
if (not len(args)):
Exception.__init__(self, "Generic State Machine Error")
else:
Exception.__init__(self, *args)
class StateMachineFatalError(StateMachineError):
"""
Fatal super class for all fatal State MAchine Exceptions
"""
def __init__(self, *args):
if (not len(args)):
Exception.__init__(self, "Fatal State Machine Error")
else:
Exception.__init__(self, *args)
def smregister(class_):
"""
State machine descedant class decorator function to register class for
SQL Alchemy mapping in magcode.core.database.utility.sqlalchemy_setup()
"""
# Process _table
if (hasattr(class_, '_table') and class_._table):
saregister(class_)
#register events with this SM
for event in class_._sm_events:
event._sm_class = class_
return(class_)
class SMEvent(Event):
"""
Base State Machine Event.
Just executes state machine. Does not get mapped into sqlalchemy.
If you modify this MODIFY SMSyncEvent as well! Thery are both
'photocopies' and are seperate just for inheritance reasons.
"""
# Private parameter to pass in SM event is associated with
_sm_class = None
def __init__(self, sm_id, *args, **kwargs):
"""
Initialise Event
"""
# Make sm_id a **kwargs to be swallowed by Event.__init__
# into the JSON parameters
super().__init__(*args, sm_id=sm_id, **kwargs)
def process(self):
"""
Execute an event on the State machine
"""
sm_obj = self._sm_class.fetch_sm_obj(self)
if (not sm_obj):
return RCODE_FATAL
# Do the state machine thing...
return_code = sm_obj.execute_state_machine(self)
# Clean up memory
del sm_obj
return return_code
class SMSyncEvent(SyncEvent):
"""
Base Syncronous State Machine Event.
Just executes state machine. Does not get mapped into sqlalchemy.
Photocopy of above SMEvent class, If you modify one MODIFY the OTHER!!
"""
# Private parameter to pass in SM event is associated with
_sm_class = None
def __init__(self, sm_id, *args, **kwargs):
"""
Initialise Event
"""
# Make sm_id a **kwargs to be swallowed by Event.__init__
# into the JSON parameters
super().__init__(*args, sm_id=sm_id, **kwargs)
def process(self):
"""
Execute an event on the State machine
"""
sm_obj = self._sm_class.fetch_sm_obj(self)
if (not sm_obj):
return RCODE_FATAL
# Do the state machine thing...
return_code = sm_obj.execute_state_machine(self)
# Clean up memory
del sm_obj
return return_code
class StateMachine(object):
"""
Base state machine object.
Contains code that is used required by all state machines.
"""
# Name of database table for SM
_table = ''
# This will be the state machine table
_sm_table = None
# List of events that need to have _sm_class set, ie every event
# list in _sm_table
_sm_events = []
@classmethod
def fetch_sm_obj(class_, event):
"""
Fetchs a State Machine object given an sm_id parameter
it an event.
event - event instance
sm_type - state machine class
returns None or sm_obj instance read in from DB.
Note: the state machine object must have an 'id' parameter
"""
sm_id = event.py_parameters.get('sm_id')
if (not sm_id):
event.state = ESTATE_FAILURE
event.py_results['message'] = "No sm_id given"
log_error("Event %s(%s) failed: No sm_id parameter"
% (event.__class__.__name__, event.id_))
return None
try:
sm_obj = event.db_session.query(class_)\
.with_lockmode('update')\
.filter(text("id = '%s'" % sm_id)).one()
except NoResultFound:
sm_obj = None
if (not sm_obj):
event.state = ESTATE_FAILURE
event.py_results['message'] = ("SM object id '%s' not found in "
"database." % sm_id)
# We typically delete SMs, still with events in the queue...
log_debug(
"Event %s(%s) failed: no state machine sm_id %s (deleted?)"
% (event.__class__.__name__, event.id_, sm_id))
return None
return sm_obj
def execute_state_machine(self, event):
"""
Execute the state machine for the given event
"""
event_id = event.id_
event_class_name = event.__class__.__name__
if (not self._sm_table):
msg = ("%s - State machine event table not filled out."
% self.__class__.__name__)
log_critical(msg)
event.py_results['message'] = msg
event.state = ESTATE_FAILURE
return RCODE_FATAL
event.py_results['pre_event_sm_state'] = self.state
action = self._sm_table[self.state].get(event.__class__)
if (not action):
msg = ("Event %s(%s) no change - state '%s'"
% (event_class_name, event_id, self.state))
log_debug(msg)
event.py_results['message'] = msg
event.state = ESTATE_SUCCESS
return RCODE_NOCHANGE
try:
(return_code, msg) = action(self, event)
except StateMachineFatalError as exc:
msg = ("Event %s(%s) failed - %s"
% (event_class_name, event_id, str_exc(exc)))
log_error(msg)
event.py_results['message'] = msg
event.py_results['sm_exception_type'] = exc.__class__.__name__
event.py_results['sm_exception_args'] = exc.args
event.state = ESTATE_FAILURE
return RCODE_FATAL
except StateMachineError as exc:
msg = ("Event %s(%s) errored - %s"
% (event_class_name, event_id, str_exc(exc)))
log_info(msg)
event.py_results['message'] = msg
event.py_results['sm_exception_type'] = exc.__class__.__name__
event.py_results['sm_exception_args'] = exc.args
event.state = ESTATE_RETRY
return RCODE_ERROR
msg = ("Event %s(%s) processed - %s."
% (event_class_name, event_id, msg))
log_info(msg)
event.state = ESTATE_SUCCESS
event.py_results['message'] = msg
event.py_results['post_event_sm_state'] = self.state
return return_code
|