Source Code for Module up2date_client.getMethod

  1  # Retrieve action method name given queued action information. 
  2  # 
  3  # Client code for Update Agent 
  4  # Copyright (c) 1999--2016 Red Hat, Inc.  Distributed under GPLv2. 
  5  # 
  6  # An allowable xmlrpc method is retrieved given a base location, a 
  7  # hierarchical route to the class/module, and method name. 
  8  # 
  9   
 10  import os 
 11  import string 
 12  import sys 
 13   
 14  from rhn.tb import raise_with_tb 
 15   
 16  try: # python2 
 17      from types import ClassType 
 18  except ImportError: # python3 
 19      ClassType = type 
 20   
 21 -class GetMethodException(Exception): 
 22      """Exception class""" 
 23      pass 
 24   
 25   
 26 -def sanity(methodNameComps): 
 27      #""" 
 28      # Verifies if all the components have proper names 
 29      #""" 
 30      # Allowed characters in each string 
 31      alpha = string.ascii_lowercase + string.ascii_uppercase 
 32      allowedChars = alpha + string.digits + '_' 
 33      for comp in methodNameComps: 
 34          if not len(comp): 
 35              raise GetMethodException("Empty method component") 
 36          for c in comp: 
 37              if c not in allowedChars: 
 38                  raise GetMethodException( 
 39                      "Invalid character '%s' in the method name" % c) 
 40          # Can only begin with a letter 
 41          if comp[0] not in alpha: 
 42              raise GetMethodException( 
 43                  "Method names should start with an alphabetic character") 
 44   
 45   
 46 -def getMethod(methodName, baseClass): 
 47      #""" 
 48      #Retreive method given methodName, path to base of tree, and class/module 
 49      #route/label. 
 50      #""" 
 51      # First split the method name 
 52      methodNameComps = baseClass.split('.') + methodName.split('.') 
 53      # Sanity checks 
 54      sanity(methodNameComps) 
 55      # Look for the module, start with the most specific 
 56      for index in range(len(methodNameComps), 0, -1): 
 57          modulename = '.'.join(methodNameComps[:index]) 
 58          try: 
 59              actions = __import__(modulename) 
 60          except ImportError: 
 61              # does not exist, try next one 
 62              continue 
 63          except Exception: 
 64              raise_with_tb(GetMethodException("Could not import module %s" % modulename)) 
 65          # found one, skip the rest 
 66          break 
 67      else: 
 68          # no module found. die 
 69          raise GetMethodException("Action %s could not be imported" % methodName) 
 70   
 71      # The position of the file 
 72      fIndex = index 
 73   
 74      className = actions 
 75      # Iterate through the list of components and try to load that specific 
 76      # module/method 
 77      for index in range(1, len(methodNameComps)): 
 78          comp = methodNameComps[index] 
 79          if index < fIndex: 
 80              # This is a directory or a file we have to load 
 81              if not hasattr(className, comp): 
 82                  # Hmmm... Not there 
 83                  raise GetMethodException("Class %s has no attribute %s" % ( 
 84                      '.'.join(methodNameComps[:index]), comp)) 
 85              className = getattr(className, comp) 
 86              #print(type(className)) 
 87              continue 
 88          # A file or method 
 89          # We look for the special __rhnexport__ array 
 90          if not hasattr(className, '__rhnexport__'): 
 91              raise GetMethodException("Class %s is not RHN-compliant" % \ 
 92                  '.'.join(methodNameComps[:index])) 
 93          export = getattr(className, '__rhnexport__') 
 94          if comp not in export: 
 95              raise GetMethodException("Class %s does not export '%s'" % ( 
 96                  '.'.join(methodNameComps[:index]), comp)) 
 97          className = getattr(className, comp) 
 98          if type(className) is ClassType: 
 99              # Try to instantiate it 
100              className = className() 
101          #print(type(className)) 
102   
103      return className 
104   
105   
106  #----------------------------------------------------------------------------- 
107  if __name__ == '__main__': 
108      # Two valid ones and a bogus one 
109      methods = [ 
110          'a.b.c.d.e.f', 
111          'a.b.c.d.e.foo.h', 
112          'a.b.c.d.e.g.h', 
113          'a.b.d.d.e.g.h', 
114          'a.b.d.d._e.g.h', 
115          'a.b.d.d.e_.g.h', 
116          'a.b.d.d.e-.g.h', 
117          'a.b.d.d..g.h', 
118      ] 
119   
120      for m in methods: 
121          print("----Running method %s: " % m) 
122          try: 
123              method = getMethod(m, 'Actions') 
124          except GetMethodException: 
125              e = sys.exc_info()[1] 
126              print("Error getting the method %s: %s" % (m, 
127                  ''.join(map(str, e.args)))) 
128          else: 
129              method() 
130  #----------------------------------------------------------------------------- 
131