Merge branch 'stable-2.6'

[ganeti-local] / lib / runtime.py

diff --git a/lib/runtime.py b/lib/runtime.py
index 4d5e3ef..883b2e5 100644 (file)
--- a/lib/runtime.py
+++ b/lib/runtime.py
@@ -1,4 +1,5 @@
 #
+#
 
 # Copyright (C) 2010 Google Inc.
 #
@@ -25,6 +26,7 @@
 import grp
 import pwd
 import threading
+import platform
 
 from ganeti import constants
 from ganeti import errors
@@ -34,6 +36,9 @@ from ganeti import utils
 _priv = None
 _priv_lock = threading.Lock()
 
+#: Architecture information
+_arch = None
+
 
 def GetUid(user, _getpwnam):
   """Retrieve the uid from the database.
@@ -73,9 +78,9 @@ class GetentResolver:
   @ivar rapi_uid: The resolved uid of the rapi user
   @ivar rapi_gid: The resolved gid of the rapi group
   @ivar noded_uid: The resolved uid of the noded user
-
   @ivar daemons_gid: The resolved gid of the daemons group
   @ivar admin_gid: The resolved gid of the admin group
+
   """
   def __init__(self, _getpwnam=pwd.getpwnam, _getgrnam=grp.getgrnam):
     """Initialize the resolver.
@@ -170,20 +175,51 @@ def GetEnts(resolver=GetentResolver):
   """Singleton wrapper around resolver instance.
 
   As this method is accessed by multiple threads at the same time
-  we need to take thread-safty carefully
+  we need to take thread-safety carefully.
 
   """
   # We need to use the global keyword here
-  global _priv # pylint: disable-msg=W0603
+  global _priv # pylint: disable=W0603
 
   if not _priv:
     _priv_lock.acquire()
     try:
       if not _priv:
         # W0621: Redefine '_priv' from outer scope (used for singleton)
-        _priv = resolver() # pylint: disable-msg=W0621
+        _priv = resolver() # pylint: disable=W0621
     finally:
       _priv_lock.release()
 
   return _priv
 
+
+def InitArchInfo():
+  """Initialize architecture information.
+
+  We can assume this information never changes during the lifetime of a
+  process, therefore the information can easily be cached.
+
+  @note: This function uses C{platform.architecture} to retrieve the Python
+    binary architecture and does so by forking to run C{file} (see Python
+    documentation for more information). Therefore it must not be used in a
+    multi-threaded environment.
+
+  """
+  global _arch # pylint: disable=W0603
+
+  if _arch is not None:
+    raise errors.ProgrammerError("Architecture information can only be"
+                                 " initialized once")
+
+  _arch = (platform.architecture()[0], platform.machine())
+
+
+def GetArchInfo():
+  """Returns previsouly initialized architecture information.
+
+  """
+  if _arch is None:
+    raise errors.ProgrammerError("Architecture information hasn't been"
+                                 " initialized")
+
+  return _arch