cmframework/src/cmframework/filebackend/cmfilebackend.py

   1 # Copyright 2019 Nokia
   2
   3 # Licensed under the Apache License, Version 2.0 (the "License");
   4 # you may not use this file except in compliance with the License.
   5 # You may obtain a copy of the License at
   6 #
   7 #     http://www.apache.org/licenses/LICENSE-2.0
   8 #
   9 # Unless required by applicable law or agreed to in writing, software
  10 # distributed under the License is distributed on an "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 # See the License for the specific language governing permissions and
  13 # limitations under the License.
  14 from __future__ import print_function
  15 import logging
  16 import re
  17 import os
  18 import stat
  19
  20 from cmframework.apis import cmbackend
  21 from cmframework.apis import cmerror
  22
  23
  24 class CMFileBackend(cmbackend.CMBackend):
  25     def __init__(self, **kw):
  26         self.uri = kw['uri']
  27         logging.debug('CMFileBackend constructor called, uri=%s', self.uri)
  28         self.data = {}
  29         self.load_file()
  30
  31     def load_file(self):
  32         logging.debug('load_file started')
  33         try:
  34             self.data = {}
  35             with open(self.uri) as f:
  36                 lines = f.read().splitlines()
  37                 for line in lines:
  38                     name, var = line.partition('=')[::2]
  39                     logging.debug('Adding %s=%s', name, var)
  40                     self.data[name.strip()] = var
  41                 f.close()
  42         except IOError:
  43             logging.debug('File %s does not exist', self.uri)
  44
  45     def write_file(self):
  46         logging.debug('write_file started')
  47         try:
  48             with open(self.uri, 'w') as f:
  49                 os.chmod(self.uri, stat.S_IRUSR | stat.S_IWUSR)
  50                 for key, value in self.data.iteritems():
  51                     logging.debug('Writing %s=%s', key, value)
  52                     f.write(key + '=' + value + '\n')
  53                 f.flush()
  54                 os.fsync(f.fileno())
  55         except IOError as exp:
  56             raise cmerror.CMError(str(exp))
  57
  58     def get_property(self, prop_name):
  59         logging.debug('get_property called for %s', prop_name)
  60         try:
  61             value = self.data[prop_name]
  62             return value
  63         except KeyError:
  64             raise cmerror.CMError('Invalid property name')
  65
  66     def get_properties(self, prop_filter):
  67         logging.debug('get_properties called with filter %s', prop_filter)
  68         returned = {}
  69         pattern = re.compile(prop_filter)
  70         for key, value in self.data.iteritems():
  71             logging.debug('Matching %s against %s', key, prop_filter)
  72             if pattern.match(key):
  73                 logging.debug('Adding %s', key)
  74                 returned[key] = value
  75         return returned
  76
  77     def set_property(self, prop_name, prop_value):
  78         logging.debug('set_property %s=%s', prop_name, prop_value)
  79         props = {}
  80         props[prop_name] = prop_value
  81         self.set_properties(props)
  82
  83     def set_properties(self, properties):
  84         logging.debug('set_properties called props=%s', str(properties))
  85         try:
  86             for key, value in properties.iteritems():
  87                 self.data[key] = value
  88             self.write_file()
  89         except cmerror.CMError:
  90             self.load_file()
  91             raise
  92
  93     def delete_property(self, prop_name):
  94         logging.debug('delete_property called for %s', prop_name)
  95         try:
  96             del self.data[prop_name]
  97             self.write_file()
  98         except KeyError:
  99             logging.debug('Property not found')
 100             raise cmerror.CMError('Property not found')
 101         except cmerror.CMError:
 102             self.load_file()
 103             raise
 104
 105     def delete_properties(self, arg):
 106         logging.debug('delete_properties called with arg %s', arg)
 107         try:
 108             if isinstance(arg, str):
 109                 pattern = re.compile(arg)
 110                 for key in self.data.keys():  # pylint: disable=consider-iterating-dictionary
 111                     if pattern.match(key):
 112                         del self.data[key]
 113             else:
 114                 for prop in arg:
 115                     for key in self.data.keys():  # pylint: disable=consider-iterating-dictionary
 116                         if key == prop:
 117                             del self.data[key]
 118             self.write_file()
 119         except cmerror.CMError:
 120             self.load_file()
 121             raise
 122
 123
 124 def main():
 125     import sys
 126
 127     filepath = sys.argv[1]
 128     try:
 129         print('Initializing backend at %s' % filepath)
 130         filebackend = CMFileBackend(uri=filepath)
 131         print('Adding key1=value1')
 132         filebackend.set_property("key1", "value1")
 133         properties = {'key2': 'value2', 'key3': 'value3'}
 134         print('Adding %s' % str(properties))
 135         filebackend.set_properties(properties)
 136         print('Getting key1')
 137         value = filebackend.get_property('key1')
 138         print('value of key1 is %s' % value)
 139         print('Deleting key2')
 140         filebackend.delete_property('key2')
 141         print('Getting *')
 142         properties = filebackend.get_properties('.*')
 143         print('Got %s' % str(properties))
 144         print('Delete all properties')
 145         filebackend.delete_properties('.*')
 146     except cmerror.CMError as exp:
 147         print('Got exeption %s' % str(exp))
 148         sys.exit(1)
 149
 150
 151 if __name__ == '__main__':
 152     main()