frappy/secop/persistent.py
Markus Zolliker fe5a2caac7 experimental persistent mixin
- still contains changes in mouduls/params ...
2021-06-04 12:19:04 +02:00

95 lines
3.6 KiB
Python

# -*- coding: utf-8 -*-
# *****************************************************************************
#
# This program 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 2 of the License, or (at your option) any later
# version.
#
# This program 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
# this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# Module authors:
# Markus Zolliker <markus.zolliker@psi.ch>
#
# *****************************************************************************
"""Define base classes for real Modules implemented in the server"""
import os
import json
from secop.errors import BadValueError, ConfigError, InternalError, \
ProgrammingError, SECoPError, SilentError, secop_error
class PersistentMixin:
def __init__(*args, **kwds):
super().__init__(*args, **kwds)
# self.persistentFile = None
# self.persistentData = {}
self.writeDict.update(self.loadParameters())
def writeInitParams(self, started_callback=None):
super().writeInitParams()
self.saveParameters()
if started_callback:
started_callback()
def loadParameters(self):
"""load persistent parameters
:return: persistent parameters which have to be written
is called upon startup and may be called from a module
when a hardware powerdown is detected
"""
persistentdir = os.path.join(getGeneralConfig()['logdir'], 'persistent')
self.persistentFile = os.path.join(persistentdir, '%s.%s.json' % (self.DISPATCHER.equipment_id, self.name))
try:
with open(self.persistentFile, 'r') as f:
self.persistentData = json.load(f)
except FileNotFoundError:
self.persistentData = {}
writeDict = {}
for pname, pobj in self.parameters.items():
if pobj.persistent and pname in self.persistentData:
value = pobj.datatype.import_value(self.persistentData[pname])
try:
pobj.value = value
if not pobj.readonly:
writeDict[pname] = value
except Exception as e:
self.log.warning('can not restore %r to %r (%r)' % (pname, value, e))
return writeDict
def saveParameters(self):
"""save persistent parameters
to be called regularely explicitly by the module
"""
data = {k: v.export_value() for k, v in self.parameters.items() if v.persistent}
if data != self.persistentData:
self.persistentData = data
persistentdir = os.path.basename(self.persistentFile)
tmpfile = self.persistentFile + '.tmp'
if not os.path.isdir(persistentdir):
os.makedirs(persistentdir, exist_ok=True)
try:
with open(tmpfile, 'w') as f:
json.dump(self.persistentData, f, indent=2)
f.write('\n')
os.rename(tmpfile, self.persistentFile)
finally:
try:
os.remove(tmpfile)
except FileNotFoundError:
pass