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Commit 1a732a74 authored by Thomas Thrainer's avatar Thomas Thrainer
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Extract base classes from cmdlib 

Base classes holding common functionality is extracted into base.py.
Utility functions used by both base classes and subclasses is moved to
common.py.
Signed-off-by: default avatarThomas Thrainer <thomasth@google.com>
Reviewed-by: default avatarBernardo Dal Seno <bdalseno@google.com>
parent 7af7da68
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Makefile.am
View file @ 1a732a74
......@@ -308,7 +308,9 @@ client_PYTHON = \
lib/client/gnt_storage.py
cmdlib_PYTHON = \
lib/cmdlib/__init__.py
lib/cmdlib/__init__.py \
lib/cmdlib/common.py \
lib/cmdlib/base.py
hypervisor_PYTHON = \
lib/hypervisor/__init__.py \
......
lib/cmdlib/__init__.py
View file @ 1a732a74
......@@ -29,7 +29,6 @@
# C0302: since we have waaaay too many lines in this module
import os
import os.path
import time
import re
import logging
......@@ -64,6 +63,11 @@ from ganeti import vcluster
from ganeti import network
from ganeti.masterd import iallocator
from ganeti.cmdlib.base import ResultWithJobs, LogicalUnit, NoHooksLU, \
Tasklet, _QueryBase
from ganeti.cmdlib.common import _ExpandInstanceName, _ExpandItemName, \
_ExpandNodeName
import ganeti.masterd.instance # pylint: disable=W0611
......@@ -78,511 +82,6 @@ CAN_CHANGE_INSTANCE_OFFLINE = (frozenset(INSTANCE_DOWN) | frozenset([
]))
class ResultWithJobs:
"""Data container for LU results with jobs.
Instances of this class returned from L{LogicalUnit.Exec} will be recognized
by L{mcpu._ProcessResult}. The latter will then submit the jobs
contained in the C{jobs} attribute and include the job IDs in the opcode
result.
"""
def __init__(self, jobs, **kwargs):
"""Initializes this class.
Additional return values can be specified as keyword arguments.
@type jobs: list of lists of L{opcode.OpCode}
@param jobs: A list of lists of opcode objects
"""
self.jobs = jobs
self.other = kwargs
class LogicalUnit(object):
"""Logical Unit base class.
Subclasses must follow these rules:
- implement ExpandNames
- implement CheckPrereq (except when tasklets are used)
- implement Exec (except when tasklets are used)
- implement BuildHooksEnv
- implement BuildHooksNodes
- redefine HPATH and HTYPE
- optionally redefine their run requirements:
REQ_BGL: the LU needs to hold the Big Ganeti Lock exclusively
Note that all commands require root permissions.
@ivar dry_run_result: the value (if any) that will be returned to the caller
in dry-run mode (signalled by opcode dry_run parameter)
"""
HPATH = None
HTYPE = None
REQ_BGL = True
def __init__(self, processor, op, context, rpc_runner):
"""Constructor for LogicalUnit.
This needs to be overridden in derived classes in order to check op
validity.
"""
self.proc = processor
self.op = op
self.cfg = context.cfg
self.glm = context.glm
# readability alias
self.owned_locks = context.glm.list_owned
self.context = context
self.rpc = rpc_runner
# Dictionaries used to declare locking needs to mcpu
self.needed_locks = None
self.share_locks = dict.fromkeys(locking.LEVELS, 0)
self.opportunistic_locks = dict.fromkeys(locking.LEVELS, False)
self.add_locks = {}
self.remove_locks = {}
# Used to force good behavior when calling helper functions
self.recalculate_locks = {}
# logging
self.Log = processor.Log # pylint: disable=C0103
self.LogWarning = processor.LogWarning # pylint: disable=C0103
self.LogInfo = processor.LogInfo # pylint: disable=C0103
self.LogStep = processor.LogStep # pylint: disable=C0103
# support for dry-run
self.dry_run_result = None
# support for generic debug attribute
if (not hasattr(self.op, "debug_level") or
not isinstance(self.op.debug_level, int)):
self.op.debug_level = 0
# Tasklets
self.tasklets = None
# Validate opcode parameters and set defaults
self.op.Validate(True)
self.CheckArguments()
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 acquired 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.
This method is called before starting to execute the opcode, and it should
update all the parameters of the opcode to their canonical form (e.g. a
short node name must be fully expanded after this method has successfully
completed). This way locking, hooks, logging, etc. can work correctly.
LUs which implement this method must also populate the self.needed_locks
member, as a dict with lock levels as keys, and a list of needed lock names
as values. Rules:
- use an empty dict if you don't need any lock
- if you don't need any lock at a particular level omit that
level (note that in this case C{DeclareLocks} won't be called
at all for that level)
- if you need locks at a level, but you can't calculate it in
this function, initialise that level with an empty list and do
further processing in L{LogicalUnit.DeclareLocks} (see that
function's docstring)
- don't put anything for the BGL level
- if you want all locks at a level use L{locking.ALL_SET} as a value
If you need to share locks (rather than acquire them exclusively) at one
level you can modify self.share_locks, setting a true value (usually 1) for
that level. By default locks are not shared.
This function can also define a list of tasklets, which then will be
executed in order instead of the usual LU-level CheckPrereq and Exec
functions, if those are not defined by the LU.
Examples::
# Acquire all nodes and one instance
self.needed_locks = {
locking.LEVEL_NODE: locking.ALL_SET,
locking.LEVEL_INSTANCE: ['instance1.example.com'],
}
# Acquire just two nodes
self.needed_locks = {
locking.LEVEL_NODE: ['node1.example.com', 'node2.example.com'],
}
# Acquire no locks
self.needed_locks = {} # No, you can't leave it to the default value None
"""
# The implementation of this method is mandatory only if the new LU is
# concurrent, so that old LUs don't need to be changed all at the same
# time.
if self.REQ_BGL:
self.needed_locks = {} # Exclusive LUs don't need locks.
else:
raise NotImplementedError
def DeclareLocks(self, level):
"""Declare LU locking needs for a level
While most LUs can just declare their locking needs at ExpandNames time,
sometimes there's the need to calculate some locks after having acquired
the ones before. This function is called just before acquiring locks at a
particular level, but after acquiring the ones at lower levels, and permits
such calculations. It can be used to modify self.needed_locks, and by
default it does nothing.
This function is only called if you have something already set in
self.needed_locks for the level.
@param level: Locking level which is going to be locked
@type level: member of L{ganeti.locking.LEVELS}
"""
def CheckPrereq(self):
"""Check prerequisites for this LU.
This method should check that the prerequisites for the execution
of this LU are fulfilled. It can do internode communication, but
it should be idempotent - no cluster or system changes are
allowed.
The method should raise errors.OpPrereqError in case something is
not fulfilled. Its return value is ignored.
This method should also update all the parameters of the opcode to
their canonical form if it hasn't been done by ExpandNames before.
"""
if self.tasklets is not None:
for (idx, tl) in enumerate(self.tasklets):
logging.debug("Checking prerequisites for tasklet %s/%s",
idx + 1, len(self.tasklets))
tl.CheckPrereq()
else:
pass
def Exec(self, feedback_fn):
"""Execute the LU.
This method should implement the actual work. It should raise
errors.OpExecError for failures that are somewhat dealt with in
code, or expected.
"""
if self.tasklets is not None:
for (idx, tl) in enumerate(self.tasklets):
logging.debug("Executing tasklet %s/%s", idx + 1, len(self.tasklets))
tl.Exec(feedback_fn)
else:
raise NotImplementedError
def BuildHooksEnv(self):
"""Build hooks environment for this LU.
@rtype: dict
@return: Dictionary containing the environment that will be used for
running the hooks for this LU. The keys of the dict must not be prefixed
with "GANETI_"--that'll be added by the hooks runner. The hooks runner
will extend the environment with additional variables. If no environment
should be defined, an empty dictionary should be returned (not C{None}).
@note: If the C{HPATH} attribute of the LU class is C{None}, this function
will not be called.
"""
raise NotImplementedError
def BuildHooksNodes(self):
"""Build list of nodes to run LU's hooks.
@rtype: tuple; (list, list)
@return: Tuple containing a list of node names on which the hook
should run before the execution and a list of node names on which the
hook should run after the execution. No nodes should be returned as an
empty list (and not None).
@note: If the C{HPATH} attribute of the LU class is C{None}, this function
will not be called.
"""
raise NotImplementedError
def HooksCallBack(self, phase, hook_results, feedback_fn, lu_result):
"""Notify the LU about the results of its hooks.
This method is called every time a hooks phase is executed, and notifies
the Logical Unit about the hooks' result. The LU can then use it to alter
its result based on the hooks. By default the method does nothing and the
previous result is passed back unchanged but any LU can define it if it
wants to use the local cluster hook-scripts somehow.
@param phase: one of L{constants.HOOKS_PHASE_POST} or
L{constants.HOOKS_PHASE_PRE}; it denotes the hooks phase
@param hook_results: the results of the multi-node hooks rpc call
@param feedback_fn: function used send feedback back to the caller
@param lu_result: the previous Exec result this LU had, or None
in the PRE phase
@return: the new Exec result, based on the previous result
and hook results
"""
# API must be kept, thus we ignore the unused argument and could
# be a function warnings
# pylint: disable=W0613,R0201
return lu_result
def _ExpandAndLockInstance(self):
"""Helper function to expand and lock an instance.
Many LUs that work on an instance take its name in self.op.instance_name
and need to expand it and then declare the expanded name for locking. This
function does it, and then updates self.op.instance_name to the expanded
name. It also initializes needed_locks as a dict, if this hasn't been done
before.
"""
if self.needed_locks is None:
self.needed_locks = {}
else:
assert locking.LEVEL_INSTANCE not in self.needed_locks, \
"_ExpandAndLockInstance called with instance-level locks set"
self.op.instance_name = _ExpandInstanceName(self.cfg,
self.op.instance_name)
self.needed_locks[locking.LEVEL_INSTANCE] = self.op.instance_name
def _LockInstancesNodes(self, primary_only=False,
level=locking.LEVEL_NODE):
"""Helper function to declare instances' nodes for locking.
This function should be called after locking one or more instances to lock
their nodes. Its effect is populating self.needed_locks[locking.LEVEL_NODE]
with all primary or secondary nodes for instances already locked and
present in self.needed_locks[locking.LEVEL_INSTANCE].
It should be called from DeclareLocks, and for safety only works if
self.recalculate_locks[locking.LEVEL_NODE] is set.
In the future it may grow parameters to just lock some instance's nodes, or
to just lock primaries or secondary nodes, if needed.
If should be called in DeclareLocks in a way similar to::
if level == locking.LEVEL_NODE:
self._LockInstancesNodes()
@type primary_only: boolean
@param primary_only: only lock primary nodes of locked instances
@param level: Which lock level to use for locking nodes
"""
assert level in self.recalculate_locks, \
"_LockInstancesNodes helper function called with no nodes to recalculate"
# TODO: check if we're really been called with the instance locks held
# For now we'll replace self.needed_locks[locking.LEVEL_NODE], but in the
# future we might want to have different behaviors depending on the value
# of self.recalculate_locks[locking.LEVEL_NODE]
wanted_nodes = []
locked_i = self.owned_locks(locking.LEVEL_INSTANCE)
for _, instance in self.cfg.GetMultiInstanceInfo(locked_i):
wanted_nodes.append(instance.primary_node)
if not primary_only:
wanted_nodes.extend(instance.secondary_nodes)
if self.recalculate_locks[level] == constants.LOCKS_REPLACE:
self.needed_locks[level] = wanted_nodes
elif self.recalculate_locks[level] == constants.LOCKS_APPEND:
self.needed_locks[level].extend(wanted_nodes)
else:
raise errors.ProgrammerError("Unknown recalculation mode")
del self.recalculate_locks[level]
class NoHooksLU(LogicalUnit): # pylint: disable=W0223
"""Simple LU which runs no hooks.
This LU is intended as a parent for other LogicalUnits which will
run no hooks, in order to reduce duplicate code.
"""
HPATH = None
HTYPE = None
def BuildHooksEnv(self):
"""Empty BuildHooksEnv for NoHooksLu.
This just raises an error.
"""
raise AssertionError("BuildHooksEnv called for NoHooksLUs")
def BuildHooksNodes(self):
"""Empty BuildHooksNodes for NoHooksLU.
"""
raise AssertionError("BuildHooksNodes called for NoHooksLU")
class Tasklet:
"""Tasklet base class.
Tasklets are subcomponents for LUs. LUs can consist entirely of tasklets or
they can mix legacy code with tasklets. Locking needs to be done in the LU,
tasklets know nothing about locks.
Subclasses must follow these rules:
- Implement CheckPrereq
- Implement Exec
"""
def __init__(self, lu):
self.lu = lu
# Shortcuts
self.cfg = lu.cfg
self.rpc = lu.rpc
def CheckPrereq(self):
"""Check prerequisites for this tasklets.
This method should check whether the prerequisites for the execution of
this tasklet are fulfilled. It can do internode communication, but it
should be idempotent - no cluster or system changes are allowed.
The method should raise errors.OpPrereqError in case something is not
fulfilled. Its return value is ignored.
This method should also update all parameters to their canonical form if it
hasn't been done before.
"""
pass
def Exec(self, feedback_fn):
"""Execute the tasklet.
This method should implement the actual work. It should raise
errors.OpExecError for failures that are somewhat dealt with in code, or
expected.
"""
raise NotImplementedError
class _QueryBase:
"""Base for query utility classes.
"""
#: Attribute holding field definitions
FIELDS = None
#: Field to sort by
SORT_FIELD = "name"
def __init__(self, qfilter, fields, use_locking):
"""Initializes this class.
"""
self.use_locking = use_locking
self.query = query.Query(self.FIELDS, fields, qfilter=qfilter,
namefield=self.SORT_FIELD)
self.requested_data = self.query.RequestedData()
self.names = self.query.RequestedNames()
# Sort only if no names were requested
self.sort_by_name = not self.names
self.do_locking = None
self.wanted = None
def _GetNames(self, lu, all_names, lock_level):
"""Helper function to determine names asked for in the query.
"""
if self.do_locking:
names = lu.owned_locks(lock_level)
else:
names = all_names
if self.wanted == locking.ALL_SET:
assert not self.names
# caller didn't specify names, so ordering is not important
return utils.NiceSort(names)
# caller specified names and we must keep the same order
assert self.names
assert not self.do_locking or lu.glm.is_owned(lock_level)
missing = set(self.wanted).difference(names)
if missing:
raise errors.OpExecError("Some items were removed before retrieving"
" their data: %s" % missing)
# Return expanded names
return self.wanted
def ExpandNames(self, lu):
"""Expand names for this query.
See L{LogicalUnit.ExpandNames}.
"""
raise NotImplementedError()
def DeclareLocks(self, lu, level):
"""Declare locks for this query.
See L{LogicalUnit.DeclareLocks}.
"""
raise NotImplementedError()
def _GetQueryData(self, lu):
"""Collects all data for this query.
@return: Query data object
"""
raise NotImplementedError()
def NewStyleQuery(self, lu):
"""Collect data and execute query.
"""
return query.GetQueryResponse(self.query, self._GetQueryData(lu),
sort_by_name=self.sort_by_name)
def OldStyleQuery(self, lu):
"""Collect data and execute query.
"""
return self.query.OldStyleQuery(self._GetQueryData(lu),
sort_by_name=self.sort_by_name)
def _ShareAll():
"""Returns a dict declaring all lock levels shared.
......@@ -1405,33 +904,6 @@ def _ComputeNewInstanceViolations(old_ipolicy, new_ipolicy, instances, cfg):
_ComputeViolatingInstances(old_ipolicy, instances, cfg))
def _ExpandItemName(fn, name, kind):
"""Expand an item name.
@param fn: the function to use for expansion
@param name: requested item name
@param kind: text description ('Node' or 'Instance')
@return: the resolved (full) name
@raise errors.OpPrereqError: if the item is not found
"""
full_name = fn(name)
if full_name is None:
raise errors.OpPrereqError("%s '%s' not known" % (kind, name),
errors.ECODE_NOENT)
return full_name
def _ExpandNodeName(cfg, name):
"""Wrapper over L{_ExpandItemName} for nodes."""
return _ExpandItemName(cfg.ExpandNodeName, name, "Node")
def _ExpandInstanceName(cfg, name):
"""Wrapper over L{_ExpandItemName} for instance."""
return _ExpandItemName(cfg.ExpandInstanceName, name, "Instance")
def _BuildNetworkHookEnv(name, subnet, gateway, network6, gateway6,
mac_prefix, tags):
"""Builds network related env variables for hooks
......
lib/cmdlib/base.py 0 → 100644
View file @ 1a732a74
<
#
#
# Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
"""Base classes and functions for cmdlib."""
import logging
from ganeti import errors
from ganeti import constants
from ganeti import locking
from ganeti import query
from ganeti import utils
from ganeti.cmdlib.common import _ExpandInstanceName
class ResultWithJobs:
"""Data container for LU results with jobs.
Instances of this class returned from L{LogicalUnit.Exec} will be recognized
by L{mcpu._ProcessResult}. The latter will then submit the jobs
contained in the C{jobs} attribute and include the job IDs in the opcode
result.
"""
def __init__(self, jobs, **kwargs):
"""Initializes this class.
Additional return values can be specified as keyword arguments.
@type jobs: list of lists of L{opcode.OpCode}
@param jobs: A list of lists of opcode objects
"""
self.jobs = jobs
self.other = kwargs
class LogicalUnit(object):
"""Logical Unit base class.
Subclasses must follow these rules:
- implement ExpandNames
- implement CheckPrereq (except when tasklets are used)
- implement Exec (except when tasklets are used)
- implement BuildHooksEnv
- implement BuildHooksNodes
- redefine HPATH and HTYPE
- optionally redefine their run requirements:
REQ_BGL: the LU needs to hold the Big Ganeti Lock exclusively
Note that all commands require root permissions.
@ivar dry_run_result: the value (if any) that will be returned to the caller
in dry-run mode (signalled by opcode dry_run parameter)
"""
HPATH = None
HTYPE = None
REQ_BGL = True
def __init__(self, processor, op, context, rpc_runner):
"""Constructor for LogicalUnit.
This needs to be overridden in derived classes in order to check op
validity.