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22 """Base classes and functions for cmdlib."""
26 from ganeti import errors
27 from ganeti import constants
28 from ganeti import locking
29 from ganeti import query
30 from ganeti import utils
31 from ganeti.cmdlib.common import ExpandInstanceName
35 """Data container for LU results with jobs.
37 Instances of this class returned from L{LogicalUnit.Exec} will be recognized
38 by L{mcpu._ProcessResult}. The latter will then submit the jobs
39 contained in the C{jobs} attribute and include the job IDs in the opcode
43 def __init__(self, jobs, **kwargs):
44 """Initializes this class.
46 Additional return values can be specified as keyword arguments.
48 @type jobs: list of lists of L{opcode.OpCode}
49 @param jobs: A list of lists of opcode objects
56 class LogicalUnit(object):
57 """Logical Unit base class.
59 Subclasses must follow these rules:
60 - implement ExpandNames
61 - implement CheckPrereq (except when tasklets are used)
62 - implement Exec (except when tasklets are used)
63 - implement BuildHooksEnv
64 - implement BuildHooksNodes
65 - redefine HPATH and HTYPE
66 - optionally redefine their run requirements:
67 REQ_BGL: the LU needs to hold the Big Ganeti Lock exclusively
69 Note that all commands require root permissions.
71 @ivar dry_run_result: the value (if any) that will be returned to the caller
72 in dry-run mode (signalled by opcode dry_run parameter)
79 def __init__(self, processor, op, context, rpc_runner):
80 """Constructor for LogicalUnit.
82 This needs to be overridden in derived classes in order to check op
88 self.cfg = context.cfg
89 self.glm = context.glm
91 self.owned_locks = context.glm.list_owned
92 self.context = context
95 # Dictionaries used to declare locking needs to mcpu
96 self.needed_locks = None
97 self.share_locks = dict.fromkeys(locking.LEVELS, 0)
98 self.opportunistic_locks = dict.fromkeys(locking.LEVELS, False)
101 self.remove_locks = {}
103 # Used to force good behavior when calling helper functions
104 self.recalculate_locks = {}
107 self.Log = processor.Log # pylint: disable=C0103
108 self.LogWarning = processor.LogWarning # pylint: disable=C0103
109 self.LogInfo = processor.LogInfo # pylint: disable=C0103
110 self.LogStep = processor.LogStep # pylint: disable=C0103
111 # support for dry-run
112 self.dry_run_result = None
113 # support for generic debug attribute
114 if (not hasattr(self.op, "debug_level") or
115 not isinstance(self.op.debug_level, int)):
116 self.op.debug_level = 0
121 # Validate opcode parameters and set defaults
122 self.op.Validate(True)
124 self.CheckArguments()
126 def CheckArguments(self):
127 """Check syntactic validity for the opcode arguments.
129 This method is for doing a simple syntactic check and ensure
130 validity of opcode parameters, without any cluster-related
131 checks. While the same can be accomplished in ExpandNames and/or
132 CheckPrereq, doing these separate is better because:
134 - ExpandNames is left as as purely a lock-related function
135 - CheckPrereq is run after we have acquired locks (and possible
138 The function is allowed to change the self.op attribute so that
139 later methods can no longer worry about missing parameters.
144 def ExpandNames(self):
145 """Expand names for this LU.
147 This method is called before starting to execute the opcode, and it should
148 update all the parameters of the opcode to their canonical form (e.g. a
149 short node name must be fully expanded after this method has successfully
150 completed). This way locking, hooks, logging, etc. can work correctly.
152 LUs which implement this method must also populate the self.needed_locks
153 member, as a dict with lock levels as keys, and a list of needed lock names
156 - use an empty dict if you don't need any lock
157 - if you don't need any lock at a particular level omit that
158 level (note that in this case C{DeclareLocks} won't be called
159 at all for that level)
160 - if you need locks at a level, but you can't calculate it in
161 this function, initialise that level with an empty list and do
162 further processing in L{LogicalUnit.DeclareLocks} (see that
163 function's docstring)
164 - don't put anything for the BGL level
165 - if you want all locks at a level use L{locking.ALL_SET} as a value
167 If you need to share locks (rather than acquire them exclusively) at one
168 level you can modify self.share_locks, setting a true value (usually 1) for
169 that level. By default locks are not shared.
171 This function can also define a list of tasklets, which then will be
172 executed in order instead of the usual LU-level CheckPrereq and Exec
173 functions, if those are not defined by the LU.
177 # Acquire all nodes and one instance
178 self.needed_locks = {
179 locking.LEVEL_NODE: locking.ALL_SET,
180 locking.LEVEL_INSTANCE: ['instance1.example.com'],
182 # Acquire just two nodes
183 self.needed_locks = {
184 locking.LEVEL_NODE: ['node1.example.com', 'node2.example.com'],
187 self.needed_locks = {} # No, you can't leave it to the default value None
190 # The implementation of this method is mandatory only if the new LU is
191 # concurrent, so that old LUs don't need to be changed all at the same
194 self.needed_locks = {} # Exclusive LUs don't need locks.
196 raise NotImplementedError
198 def DeclareLocks(self, level):
199 """Declare LU locking needs for a level
201 While most LUs can just declare their locking needs at ExpandNames time,
202 sometimes there's the need to calculate some locks after having acquired
203 the ones before. This function is called just before acquiring locks at a
204 particular level, but after acquiring the ones at lower levels, and permits
205 such calculations. It can be used to modify self.needed_locks, and by
206 default it does nothing.
208 This function is only called if you have something already set in
209 self.needed_locks for the level.
211 @param level: Locking level which is going to be locked
212 @type level: member of L{ganeti.locking.LEVELS}
216 def CheckPrereq(self):
217 """Check prerequisites for this LU.
219 This method should check that the prerequisites for the execution
220 of this LU are fulfilled. It can do internode communication, but
221 it should be idempotent - no cluster or system changes are
224 The method should raise errors.OpPrereqError in case something is
225 not fulfilled. Its return value is ignored.
227 This method should also update all the parameters of the opcode to
228 their canonical form if it hasn't been done by ExpandNames before.
231 if self.tasklets is not None:
232 for (idx, tl) in enumerate(self.tasklets):
233 logging.debug("Checking prerequisites for tasklet %s/%s",
234 idx + 1, len(self.tasklets))
239 def Exec(self, feedback_fn):
242 This method should implement the actual work. It should raise
243 errors.OpExecError for failures that are somewhat dealt with in
247 if self.tasklets is not None:
248 for (idx, tl) in enumerate(self.tasklets):
249 logging.debug("Executing tasklet %s/%s", idx + 1, len(self.tasklets))
252 raise NotImplementedError
254 def BuildHooksEnv(self):
255 """Build hooks environment for this LU.
258 @return: Dictionary containing the environment that will be used for
259 running the hooks for this LU. The keys of the dict must not be prefixed
260 with "GANETI_"--that'll be added by the hooks runner. The hooks runner
261 will extend the environment with additional variables. If no environment
262 should be defined, an empty dictionary should be returned (not C{None}).
263 @note: If the C{HPATH} attribute of the LU class is C{None}, this function
267 raise NotImplementedError
269 def BuildHooksNodes(self):
270 """Build list of nodes to run LU's hooks.
272 @rtype: tuple; (list, list)
273 @return: Tuple containing a list of node names on which the hook
274 should run before the execution and a list of node names on which the
275 hook should run after the execution. No nodes should be returned as an
276 empty list (and not None).
277 @note: If the C{HPATH} attribute of the LU class is C{None}, this function
281 raise NotImplementedError
283 def HooksCallBack(self, phase, hook_results, feedback_fn, lu_result):
284 """Notify the LU about the results of its hooks.
286 This method is called every time a hooks phase is executed, and notifies
287 the Logical Unit about the hooks' result. The LU can then use it to alter
288 its result based on the hooks. By default the method does nothing and the
289 previous result is passed back unchanged but any LU can define it if it
290 wants to use the local cluster hook-scripts somehow.
292 @param phase: one of L{constants.HOOKS_PHASE_POST} or
293 L{constants.HOOKS_PHASE_PRE}; it denotes the hooks phase
294 @param hook_results: the results of the multi-node hooks rpc call
295 @param feedback_fn: function used send feedback back to the caller
296 @param lu_result: the previous Exec result this LU had, or None
298 @return: the new Exec result, based on the previous result
302 # API must be kept, thus we ignore the unused argument and could
303 # be a function warnings
304 # pylint: disable=W0613,R0201
307 def _ExpandAndLockInstance(self):
308 """Helper function to expand and lock an instance.
310 Many LUs that work on an instance take its name in self.op.instance_name
311 and need to expand it and then declare the expanded name for locking. This
312 function does it, and then updates self.op.instance_name to the expanded
313 name. It also initializes needed_locks as a dict, if this hasn't been done
317 if self.needed_locks is None:
318 self.needed_locks = {}
320 assert locking.LEVEL_INSTANCE not in self.needed_locks, \
321 "_ExpandAndLockInstance called with instance-level locks set"
322 self.op.instance_name = ExpandInstanceName(self.cfg,
323 self.op.instance_name)
324 self.needed_locks[locking.LEVEL_INSTANCE] = self.op.instance_name
326 def _LockInstancesNodes(self, primary_only=False,
327 level=locking.LEVEL_NODE):
328 """Helper function to declare instances' nodes for locking.
330 This function should be called after locking one or more instances to lock
331 their nodes. Its effect is populating self.needed_locks[locking.LEVEL_NODE]
332 with all primary or secondary nodes for instances already locked and
333 present in self.needed_locks[locking.LEVEL_INSTANCE].
335 It should be called from DeclareLocks, and for safety only works if
336 self.recalculate_locks[locking.LEVEL_NODE] is set.
338 In the future it may grow parameters to just lock some instance's nodes, or
339 to just lock primaries or secondary nodes, if needed.
341 If should be called in DeclareLocks in a way similar to::
343 if level == locking.LEVEL_NODE:
344 self._LockInstancesNodes()
346 @type primary_only: boolean
347 @param primary_only: only lock primary nodes of locked instances
348 @param level: Which lock level to use for locking nodes
351 assert level in self.recalculate_locks, \
352 "_LockInstancesNodes helper function called with no nodes to recalculate"
354 # TODO: check if we're really been called with the instance locks held
356 # For now we'll replace self.needed_locks[locking.LEVEL_NODE], but in the
357 # future we might want to have different behaviors depending on the value
358 # of self.recalculate_locks[locking.LEVEL_NODE]
360 locked_i = self.owned_locks(locking.LEVEL_INSTANCE)
361 for _, instance in self.cfg.GetMultiInstanceInfo(locked_i):
362 wanted_nodes.append(instance.primary_node)
364 wanted_nodes.extend(instance.secondary_nodes)
366 if self.recalculate_locks[level] == constants.LOCKS_REPLACE:
367 self.needed_locks[level] = wanted_nodes
368 elif self.recalculate_locks[level] == constants.LOCKS_APPEND:
369 self.needed_locks[level].extend(wanted_nodes)
371 raise errors.ProgrammerError("Unknown recalculation mode")
373 del self.recalculate_locks[level]
376 class NoHooksLU(LogicalUnit): # pylint: disable=W0223
377 """Simple LU which runs no hooks.
379 This LU is intended as a parent for other LogicalUnits which will
380 run no hooks, in order to reduce duplicate code.
386 def BuildHooksEnv(self):
387 """Empty BuildHooksEnv for NoHooksLu.
389 This just raises an error.
392 raise AssertionError("BuildHooksEnv called for NoHooksLUs")
394 def BuildHooksNodes(self):
395 """Empty BuildHooksNodes for NoHooksLU.
398 raise AssertionError("BuildHooksNodes called for NoHooksLU")
402 """Tasklet base class.
404 Tasklets are subcomponents for LUs. LUs can consist entirely of tasklets or
405 they can mix legacy code with tasklets. Locking needs to be done in the LU,
406 tasklets know nothing about locks.
408 Subclasses must follow these rules:
409 - Implement CheckPrereq
413 def __init__(self, lu):
420 def CheckPrereq(self):
421 """Check prerequisites for this tasklets.
423 This method should check whether the prerequisites for the execution of
424 this tasklet are fulfilled. It can do internode communication, but it
425 should be idempotent - no cluster or system changes are allowed.
427 The method should raise errors.OpPrereqError in case something is not
428 fulfilled. Its return value is ignored.
430 This method should also update all parameters to their canonical form if it
431 hasn't been done before.
436 def Exec(self, feedback_fn):
437 """Execute the tasklet.
439 This method should implement the actual work. It should raise
440 errors.OpExecError for failures that are somewhat dealt with in code, or
444 raise NotImplementedError
448 """Base for query utility classes.
451 #: Attribute holding field definitions
457 def __init__(self, qfilter, fields, use_locking):
458 """Initializes this class.
461 self.use_locking = use_locking
463 self.query = query.Query(self.FIELDS, fields, qfilter=qfilter,
464 namefield=self.SORT_FIELD)
465 self.requested_data = self.query.RequestedData()
466 self.names = self.query.RequestedNames()
468 # Sort only if no names were requested
469 self.sort_by_name = not self.names
471 self.do_locking = None
474 def _GetNames(self, lu, all_names, lock_level):
475 """Helper function to determine names asked for in the query.
479 names = lu.owned_locks(lock_level)
483 if self.wanted == locking.ALL_SET:
484 assert not self.names
485 # caller didn't specify names, so ordering is not important
486 return utils.NiceSort(names)
488 # caller specified names and we must keep the same order
490 assert not self.do_locking or lu.glm.is_owned(lock_level)
492 missing = set(self.wanted).difference(names)
494 raise errors.OpExecError("Some items were removed before retrieving"
495 " their data: %s" % missing)
497 # Return expanded names
500 def ExpandNames(self, lu):
501 """Expand names for this query.
503 See L{LogicalUnit.ExpandNames}.
506 raise NotImplementedError()
508 def DeclareLocks(self, lu, level):
509 """Declare locks for this query.
511 See L{LogicalUnit.DeclareLocks}.
514 raise NotImplementedError()
516 def _GetQueryData(self, lu):
517 """Collects all data for this query.
519 @return: Query data object
522 raise NotImplementedError()
524 def NewStyleQuery(self, lu):
525 """Collect data and execute query.
528 return query.GetQueryResponse(self.query, self._GetQueryData(lu),
529 sort_by_name=self.sort_by_name)
531 def OldStyleQuery(self, lu):
532 """Collect data and execute query.
535 return self.query.OldStyleQuery(self._GetQueryData(lu),
536 sort_by_name=self.sort_by_name)