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