Xen: remove two end-of-line semicolons

[ganeti-local] / lib / ssconf.py

diff --git a/lib/ssconf.py b/lib/ssconf.py
index de9cdbc..fbe2fb1 100644 (file)
--- a/lib/ssconf.py
+++ b/lib/ssconf.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#
 #
 
 # Copyright (C) 2006, 2007 Google Inc.
@@ -26,13 +26,12 @@ configuration data, which is mostly static and available to all nodes.
 
 """
 
-import os
-import tempfile
-import errno
 import socket
+import sys
 
 from ganeti import errors
 from ganeti import constants
+from ganeti import utils
 
 
 class SimpleStore:
@@ -49,9 +48,7 @@ class SimpleStore:
   Other particularities of the datastore:
     - keys are restricted to predefined values
     - values are small (<4k)
-    - since the data is practically static, read keys are cached in memory
-    - some keys are handled specially (read from the system, so
-      we can't update them)
+    - some keys are handled specially (read from the system)
 
   """
   _SS_FILEPREFIX = "ssconf_"
@@ -61,8 +58,11 @@ class SimpleStore:
   SS_MASTER_IP = "master_ip"
   SS_MASTER_NETDEV = "master_netdev"
   SS_CLUSTER_NAME = "cluster_name"
+  SS_FILE_STORAGE_DIR = "file_storage_dir"
+  SS_CONFIG_VERSION = "config_version"
   _VALID_KEYS = (SS_HYPERVISOR, SS_NODED_PASS, SS_MASTER_NODE, SS_MASTER_IP,
-                 SS_MASTER_NETDEV, SS_CLUSTER_NAME)
+                 SS_MASTER_NETDEV, SS_CLUSTER_NAME, SS_FILE_STORAGE_DIR,
+                 SS_CONFIG_VERSION)
   _MAX_SIZE = 4096
 
   def __init__(self, cfg_location=None):
@@ -70,7 +70,6 @@ class SimpleStore:
       self._cfg_dir = constants.DATA_DIR
     else:
       self._cfg_dir = cfg_location
-    self._cache = {}
 
   def KeyToFilename(self, key):
     """Convert a given key into filename.
@@ -90,8 +89,6 @@ class SimpleStore:
     will be changed into ConfigurationErrors.
 
     """
-    if key in self._cache:
-      return self._cache[key]
     filename = self.KeyToFilename(key)
     try:
       fh = file(filename, 'r')
@@ -103,7 +100,6 @@ class SimpleStore:
     except EnvironmentError, err:
       raise errors.ConfigurationError("Can't read from the ssconf file:"
                                       " '%s'" % str(err))
-    self._cache[key] = data
     return data
 
   def GetNodeDaemonPort(self):
@@ -157,36 +153,85 @@ class SimpleStore:
     """
     return self._ReadFile(self.SS_CLUSTER_NAME)
 
-  def SetKey(self, key, value):
-    """Set the value of a key.
+  def GetFileStorageDir(self):
+    """Get the file storage dir.
+
+    """
+    return self._ReadFile(self.SS_FILE_STORAGE_DIR)
 
-    This should be used only when adding a node to a cluster.
+  def GetConfigVersion(self):
+    """Get the configuration version.
 
     """
-    file_name = self.KeyToFilename(key)
-    dir_name, small_name = os.path.split(file_name)
-    fd, new_name = tempfile.mkstemp('.new', small_name, dir_name)
-    # here we need to make sure we remove the temp file, if any error
-    # leaves it in place
+    value = self._ReadFile(self.SS_CONFIG_VERSION)
     try:
-      os.chown(new_name, 0, 0)
-      os.chmod(new_name, 0400)
-      os.write(fd, "%s\n" % str(value))
-      os.fsync(fd)
-      os.rename(new_name, file_name)
-      self._cache[key] = value
-    finally:
-      os.close(fd)
-      try:
-        os.unlink(new_name)
-      except OSError, err:
-        if err.errno != errno.ENOENT:
-          raise
+      return int(value)
+    except (ValueError, TypeError), err:
+      raise errors.ConfigurationError("Failed to convert config version %s to"
+                                      " int: '%s'" % (value, str(err)))
 
   def GetFileList(self):
-    """Return the lis of all config files.
+    """Return the list of all config files.
 
     This is used for computing node replication data.
 
     """
     return [self.KeyToFilename(key) for key in self._VALID_KEYS]
+
+
+class WritableSimpleStore(SimpleStore):
+  """This is a read/write interface to SimpleStore, which is used rarely, when
+  values need to be changed. Since WriteFile handles updates in an atomic way
+  it should be fine to use two WritableSimpleStore at the same time, but in
+  the future we might want to put additional protection for this class.
+
+  A WritableSimpleStore cannot be used to update system-dependent values.
+
+  """
+
+  def SetKey(self, key, value):
+    """Set the value of a key.
+
+    This should be used only when adding a node to a cluster, or in other
+    infrequent operations such as cluster-rename or master-failover.
+
+    """
+    file_name = self.KeyToFilename(key)
+    utils.WriteFile(file_name, data="%s\n" % str(value),
+                    uid=0, gid=0, mode=0400)
+
+
+def GetMasterAndMyself(ss=None):
+  """Get the master node and my own hostname.
+
+  This can be either used for a 'soft' check (compared to CheckMaster,
+  which exits) or just for computing both at the same time.
+
+  The function does not handle any errors, these should be handled in
+  the caller (errors.ConfigurationError, errors.ResolverError).
+
+  """
+  if ss is None:
+    ss = SimpleStore()
+  return ss.GetMasterNode(), utils.HostInfo().name
+
+def CheckMaster(debug, ss=None):
+  """Checks the node setup.
+
+  If this is the master, the function will return. Otherwise it will
+  exit with an exit code based on the node status.
+
+  """
+  try:
+    master_name, myself = GetMasterAndMyself(ss)
+  except errors.ConfigurationError, err:
+    print "Cluster configuration incomplete: '%s'" % str(err)
+    sys.exit(constants.EXIT_NODESETUP_ERROR)
+  except errors.ResolverError, err:
+    sys.stderr.write("Cannot resolve my own name (%s)\n" % err.args[0])
+    sys.exit(constants.EXIT_NODESETUP_ERROR)
+
+  if myself != master_name:
+    if debug:
+      sys.stderr.write("Not master, exiting.\n")
+    sys.exit(constants.EXIT_NOTMASTER)