database.py

   1 import os
   2 import sys
   3 import pickle
   4 noserial=False
   5 try:
   6         from PHPSerialize import *
   7         from PHPUnserialize import *
   8 except:
   9         #print >>sys.stderr, "PHPSerial db type not allowed."
  10         noserial=True
  11
  12 import inspect
  13 import shutil
  14 from config import config as cfg
  15 config = cfg()
  16
  17 import monitorconfig
  18
  19 DEBUG= 0
  20 PICKLE_PATH=monitorconfig.MONITOR_DATA_ROOT
  21
  22 class ExceptionTimeout(Exception): pass
  23
  24 def dbLoad(name, type=None):
  25         return SPickle().load(name, type)
  26
  27 def dbExists(name, type=None):
  28         #if self.config.debug:
  29         #       name = "debug.%s" % name
  30         return SPickle().exists(name, type)
  31
  32 def dbDump(name, obj=None, type=None):
  33         # depth of the dump is 2 now, since we're redirecting to '.dump'
  34         return SPickle().dump(name, obj, type, 2)
  35
  36 def if_cached_else_refresh(cond, refresh, name, function, type=None):
  37         s = SPickle()
  38         if refresh:
  39                 if not config.debug and s.exists("production.%s" % name, type):
  40                         s.remove("production.%s" % name, type)
  41                 if config.debug and s.exists("debug.%s" % name, type):
  42                         s.remove("debug.%s" % name, type)
  43
  44         return if_cached_else(cond, name, function, type)
  45
  46 def if_cached_else(cond, name, function, type=None):
  47         s = SPickle()
  48         if (cond and s.exists("production.%s" % name, type)) or \
  49            (cond and config.debug and s.exists("debug.%s" % name, type)):
  50                 o = s.load(name, type)
  51         else:
  52                 o = function()
  53                 if cond:
  54                         s.dump(name, o, type)   # cache the object using 'name'
  55                         o = s.load(name, type)
  56                 # TODO: what if 'o' hasn't been converted...
  57         return o
  58
  59 class SPickle:
  60         def __init__(self, path=PICKLE_PATH):
  61                 self.path = path
  62
  63         def if_cached_else(self, cond, name, function, type=None):
  64                 if cond and self.exists("production.%s" % name, type):
  65                         o = self.load(name, type)
  66                 else:
  67                         o = function()
  68                         if cond:
  69                                 self.dump(name, o, type)        # cache the object using 'name'
  70                 return o
  71
  72         def __file(self, name, type=None):
  73                 if type == None:
  74                         return "%s/%s.pkl" % (self.path, name)
  75                 else:
  76                         if noserial:
  77                                 raise Exception("No PHPSerializer module available")
  78
  79                         return "%s/%s.phpserial" % (self.path, name)
  80
  81         def exists(self, name, type=None):
  82                 return os.path.exists(self.__file(name, type))
  83
  84         def remove(self, name, type=None):
  85                 return os.remove(self.__file(name, type))
  86
  87         def load(self, name, type=None):
  88                 """
  89                 In debug mode, we should fail if neither file exists.
  90                         if the debug file exists, reset name
  91                         elif the original file exists, make a copy, reset name
  92                         else neither exist, raise an error
  93                 Otherwise, it's normal mode, if the file doesn't exist, raise error
  94                 Load the file
  95                 """
  96
  97                 if config.debug:
  98                         if self.exists("debug.%s" % name, type):
  99                                 name = "debug.%s" % name
 100                         elif self.exists("production.%s" % name, type):
 101                                 debugname = "debug.%s" % name
 102                                 if not self.exists(debugname, type):
 103                                         name = "production.%s" % name
 104                                         shutil.copyfile(self.__file(name, type), self.__file(debugname, type))
 105                                 name = debugname
 106                         else:   # neither exist
 107                                 raise Exception, "No such pickle based on %s" % self.__file("debug.%s" % name, type)
 108                 else:
 109                         if   self.exists("production.%s" % name, type):
 110                                 name = "production.%s" % name
 111                         elif self.exists(name, type):
 112                                 name = name
 113                         else:
 114                                 raise Exception, "No such file %s" % name
 115
 116
 117                 #print "loading %s" % self.__file(name, type)
 118                 f = open(self.__file(name, type), 'r')
 119                 if type == None:
 120                         o = pickle.load(f)
 121                 else:
 122                         if noserial:
 123                                 raise Exception("No PHPSerializer module available")
 124                         s = PHPUnserialize()
 125                         o = s.unserialize(f.read())
 126                 f.close()
 127                 return o
 128
 129
 130         # use the environment to extract the data associated with the local
 131         # variable 'name'
 132         def dump(self, name, obj=None, type=None, depth=1):
 133                 if obj == None:
 134                         o = inspect.getouterframes(inspect.currentframe())
 135                         up1 = o[depth][0] # get the frame one prior to (up from) this frame
 136                         argvals = inspect.getargvalues(up1)
 137                         # TODO: check that 'name' is a local variable; otherwise this would fail.
 138                         obj = argvals[3][name] # extract the local variable name 'name'
 139                 if not os.path.isdir("%s/" % self.path):
 140                         os.mkdir("%s" % self.path)
 141                 if config.debug:
 142                         name = "debug.%s" % name
 143                 else:
 144                         name = "production.%s" % name
 145                 f = open(self.__file(name, type), 'w')
 146                 if type == None:
 147                         pickle.dump(obj, f)
 148                 else:
 149                         if noserial:
 150                                 raise Exception("No PHPSerializer module available")
 151                         s = PHPSerialize()
 152                         f.write(s.serialize(obj))
 153                 f.close()
 154                 return