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  """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 ExpandInstanceUuidAndName
  
  
  class ResultWithJobs(object):
    """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 LUWConfdClient(object):
    """Wrapper class for wconfd client calls from LUs.
  
    Correctly updates the cache of the LU's owned locks
    when leaving. Also transparently adds the context
    for resource requests.
  
    """
    def __init__(self, lu):
      self.lu = lu
  
    def TryUpdateLocks(self, req):
      self.lu.wconfd.Client().TryUpdateLocks(self.lu.wconfdcontext, req)
      self.lu.wconfdlocks = \
        self.lu.wconfd.Client().ListLocks(self.lu.wconfdcontext)
  
    def DownGradeLocksLevel(self, level):
      self.lu.wconfd.Client().DownGradeLocksLevel(self.lu.wconfdcontext, level)
      self.lu.wconfdlocks = \
        self.lu.wconfd.Client().ListLocks(self.lu.wconfdcontext)
  
    def FreeLocksLevel(self, level):
      self.lu.wconfd.Client().FreeLocksLevel(self.lu.wconfdcontext, level)
      self.lu.wconfdlocks = \
        self.lu.wconfd.Client().ListLocks(self.lu.wconfdcontext)
  
  
  class LogicalUnit(object): # pylint: disable=R0902
    """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)
  
    """
    # This class has more than 20 instance variables, but at most have sensible
    # defaults and are used in a declartive way, this is not a problem.
  
    HPATH = None
    HTYPE = None
    REQ_BGL = True
  
    def __init__(self, processor, op, cfg,
                 rpc_runner, wconfdcontext, wconfd):
      """Constructor for LogicalUnit.
  
      This needs to be overridden in derived classes in order to check op
      validity.
  
      @type wconfdcontext: (int, string)
      @param wconfdcontext: the identity of the logical unit to represent itself
          to wconfd when asking for resources; it is given as job id and livelock
          file.
      @param wconfd: the wconfd class to use; dependency injection to allow
          testability.
  
      """
      self.proc = processor
      self.op = op
      self.cfg = cfg
      self.wconfdlocks = []
      self.wconfdcontext = wconfdcontext
      self.rpc = rpc_runner
      self.wconfd = wconfd # wconfd module to use, for testing
  
      # 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.opportunistic_locks_count = dict.fromkeys(locking.LEVELS, 1)
      self.dont_collate_locks = dict.fromkeys(locking.LEVELS, False)
  
      self.add_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 WConfdClient(self):
      return LUWConfdClient(self)
  
    def owned_locks(self, level):
      """Return the list of locks owned by the LU at a given level.
  
      This method assumes that is field wconfdlocks is set correctly
      by mcpu.
  
      """
      levelprefix = "%s/" % (locking.LEVEL_NAMES[level],)
      locks = set([lock[0][len(levelprefix):]
                  for lock in self.wconfdlocks
                  if lock[0].startswith(levelprefix)])
      expand_fns = {
        locking.LEVEL_CLUSTER: (lambda: [locking.BGL]),
        locking.LEVEL_INSTANCE:
          lambda: self.cfg.GetInstanceNames(self.cfg.GetInstanceList()),
        locking.LEVEL_NODEGROUP: self.cfg.GetNodeGroupList,
        locking.LEVEL_NODE: self.cfg.GetNodeList,
        locking.LEVEL_NODE_RES: self.cfg.GetNodeList,
        locking.LEVEL_NETWORK: self.cfg.GetNetworkList,
        }
      if locking.LOCKSET_NAME in locks:
        return expand_fns[level]()
      else:
        return locks
  
    def release_request(self, level, names):
      """Return a request to release the specified locks of the given level.
  
      Correctly break up the group lock to do so.
  
      """
      levelprefix = "%s/" % (locking.LEVEL_NAMES[level],)
      release = [[levelprefix + lock, "release"] for lock in names]
  
      # if we break up the set-lock, make sure we ask for the rest of it.
      setlock = levelprefix + locking.LOCKSET_NAME
      if [setlock, "exclusive"] in self.wconfdlocks:
        owned = self.owned_locks(level)
        request = [[levelprefix + lock, "exclusive"]
                   for lock in owned
                   if lock not in names]
      elif [setlock, "shared"] in self.wconfdlocks:
        owned = self.owned_locks(level)
        request = [[levelprefix + lock, "shared"]
                   for lock in owned
                   if lock not in names]
      else:
        request = []
  
      return release + [[setlock, "release"]] + request
  
    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-uuid', 'node2-uuid'],
        }
        # 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 PrepareRetry(self, _feedback_fn):
      """Prepare the LU to run again.
  
      This method is called if the Exec failed for temporarily lacking resources.
      It is expected to change the state of the LU so that it can be tried again,
      and also change its locking policy to acquire more resources to have a
      better chance of suceeding in the retry.
  
      """
      # pylint: disable=R0201
      raise errors.OpRetryNotSupportedError()
  
    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 UUIDs on which the hook
        should run before the execution and a list of node UUIDs 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 PreparePostHookNodes(self, post_hook_node_uuids):
      """Extend list of nodes to run the post LU hook.
  
      This method allows LUs to change the list of node UUIDs on which the
      post hook should run after the LU has been executed but before the post
      hook is run.
  
      @type post_hook_node_uuids: list
      @param post_hook_node_uuids: The initial list of node UUIDs to run the
        post hook on, as returned by L{BuildHooksNodes}.
      @rtype: list
      @return: list of node UUIDs on which the post hook should run. The default
        implementation returns the passed in C{post_hook_node_uuids}, but
        custom implementations can choose to alter the list.
  
      """
      # For consistency with HooksCallBack we ignore the "could be a function"
      # warning
      # pylint: disable=R0201
      return post_hook_node_uuids
  
    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, allow_forthcoming=False):
      """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.
  
      @param allow_forthcoming: if True, do not insist that the intsance be real;
          the default behaviour is to raise a prerequisite error if the specified
          instance is forthcoming.
  
      """
      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_uuid, self.op.instance_name) = \
        ExpandInstanceUuidAndName(self.cfg, self.op.instance_uuid,
                                  self.op.instance_name)
      self.needed_locks[locking.LEVEL_INSTANCE] = self.op.instance_name
      if not allow_forthcoming:
        if self.cfg.GetInstanceInfo(self.op.instance_uuid).forthcoming:
          raise errors.OpPrereqError(
            "forthcoming instances not supported for this operation")
  
    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_node_uuids = []
      locked_i = self.owned_locks(locking.LEVEL_INSTANCE)
      for _, instance in self.cfg.GetMultiInstanceInfoByName(locked_i):
        wanted_node_uuids.append(instance.primary_node)
        if not primary_only:
          wanted_node_uuids.extend(
            self.cfg.GetInstanceSecondaryNodes(instance.uuid))
  
      if self.recalculate_locks[level] == constants.LOCKS_REPLACE:
        self.needed_locks[level] = wanted_node_uuids
      elif self.recalculate_locks[level] == constants.LOCKS_APPEND:
        self.needed_locks[level].extend(wanted_node_uuids)
      else:
        raise errors.ProgrammerError("Unknown recalculation mode")
  
      del self.recalculate_locks[level]
  
    def AssertReleasedLocks(self, level):
      """Raise AssertionError if the LU holds some locks of the given level.
  
      """
      assert not self.owned_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")
  
    def PreparePostHookNodes(self, post_hook_node_uuids):
      """Empty PreparePostHookNodes for NoHooksLU.
  
      """
      raise AssertionError("PreparePostHookNodes called for NoHooksLU")
  
  
  class Tasklet(object):
    """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(object):
    """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
  
      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)
  