From 4be4691d5be0f08780678b18f75ed55b03fdba57 Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Tue, 25 Nov 2008 12:57:13 +0000
Subject: [PATCH] Slight change to the LU initialization code
This patch adds support for a separate LU.CheckArguments() method which
should do syntactic checks without holding locks and without polluting
the ExpandNames which is a lock-related function. See for example the
FIXME in LUSetInstanceParams.CheckPrereq.
The patch also removes the REQ_MASTER and IsCluster checks since with
the current architecture, inside LU code we are always in a valid
cluster and we are always running on the master node.
Reviewed-by: ultrotter
---
lib/cmdlib.py | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index dff156513..2459dd198 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -54,7 +54,6 @@ class LogicalUnit(object):
- implement BuildHooksEnv
- redefine HPATH and HTYPE
- optionally redefine their run requirements:
- REQ_MASTER: the LU needs to run on the master node
REQ_BGL: the LU needs to hold the Big Ganeti Lock exclusively
Note that all commands require root permissions.
@@ -63,7 +62,6 @@ class LogicalUnit(object):
HPATH = None
HTYPE = None
_OP_REQP = []
- REQ_MASTER = True
REQ_BGL = True
def __init__(self, processor, op, context, rpc):
@@ -96,15 +94,7 @@ class LogicalUnit(object):
if attr_val is None:
raise errors.OpPrereqError("Required parameter '%s' missing" %
attr_name)
-
- if not self.cfg.IsCluster():
- raise errors.OpPrereqError("Cluster not initialized yet,"
- " use 'gnt-cluster init' first.")
- if self.REQ_MASTER:
- master = self.cfg.GetMasterNode()
- if master != utils.HostInfo().name:
- raise errors.OpPrereqError("Commands must be run on the master"
- " node %s" % master)
+ self.CheckArguments()
def __GetSSH(self):
"""Returns the SshRunner object
@@ -116,6 +106,24 @@ class LogicalUnit(object):
ssh = property(fget=__GetSSH)
+ def CheckArguments(self):
+ """Check syntactic validity for the opcode arguments.
+
+ This method is for doing a simple syntactic check and ensure
+ validity of opcode parameters, without any cluster-related
+ checks. While the same can be accomplished in ExpandNames and/or
+ CheckPrereq, doing these separate is better because:
+
+ - ExpandNames is left as as purely a lock-related function
+ - CheckPrereq is run after we have aquired locks (and possible
+ waited for them)
+
+ The function is allowed to change the self.op attribute so that
+ later methods can no longer worry about missing parameters.
+
+ """
+ pass
+
def ExpandNames(self):
"""Expand names for this LU.
@@ -1947,7 +1955,6 @@ class LUQueryClusterInfo(NoHooksLU):
"""
_OP_REQP = []
- REQ_MASTER = False
REQ_BGL = False
def ExpandNames(self):
--
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