Synnefo » snf-ganeti

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# Copyright (C) 2006, 2007, 2011, 2012 Google Inc.

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"""Module implementing the logic for running hooks.

"""

from ganeti import constants

from ganeti import errors

from ganeti import utils

from ganeti import compat

from ganeti import pathutils

def _RpcResultsToHooksResults(rpc_results):

  """Function to convert RPC results to the format expected by HooksMaster.

  @type rpc_results: dict(node: L{rpc.RpcResult})

  @param rpc_results: RPC results

  @rtype: dict(node: (fail_msg, offline, hooks_results))

  @return: RPC results unpacked according to the format expected by

    L({hooksmaster.HooksMaster}

  """

  return dict((node, (rpc_res.fail_msg, rpc_res.offline, rpc_res.payload))

              for (node, rpc_res) in rpc_results.items())

class HooksMaster(object):

  def __init__(self, opcode, hooks_path, nodes, hooks_execution_fn,

               hooks_results_adapt_fn, build_env_fn, log_fn, htype=None,

               cluster_name=None, master_name=None):

    """Base class for hooks masters.

    This class invokes the execution of hooks according to the behaviour

    specified by its parameters.

    @type opcode: string

    @param opcode: opcode of the operation to which the hooks are tied

    @type hooks_path: string

    @param hooks_path: prefix of the hooks directories

    @type nodes: 2-tuple of lists

    @param nodes: 2-tuple of lists containing nodes on which pre-hooks must be

      run and nodes on which post-hooks must be run

    @type hooks_execution_fn: function that accepts the following parameters:

      (node_list, hooks_path, phase, environment)

    @param hooks_execution_fn: function that will execute the hooks; can be

      None, indicating that no conversion is necessary.

    @type hooks_results_adapt_fn: function

    @param hooks_results_adapt_fn: function that will adapt the return value of

      hooks_execution_fn to the format expected by RunPhase

    @type build_env_fn: function that returns a dictionary having strings as

      keys

    @param build_env_fn: function that builds the environment for the hooks

    @type log_fn: function that accepts a string

    @param log_fn: logging function

    @type htype: string or None

    @param htype: None or one of L{constants.HTYPE_CLUSTER},

     L{constants.HTYPE_NODE}, L{constants.HTYPE_INSTANCE}

    @type cluster_name: string

    @param cluster_name: name of the cluster

    @type master_name: string

    @param master_name: name of the master

    """

    self.opcode = opcode

    self.hooks_path = hooks_path

    self.hooks_execution_fn = hooks_execution_fn

    self.hooks_results_adapt_fn = hooks_results_adapt_fn

    self.build_env_fn = build_env_fn

    self.log_fn = log_fn

    self.htype = htype

    self.cluster_name = cluster_name

    self.master_name = master_name

    self.pre_env = self._BuildEnv(constants.HOOKS_PHASE_PRE)

    (self.pre_nodes, self.post_nodes) = nodes

  def _BuildEnv(self, phase):

    """Compute the environment and the target nodes.

    Based on the opcode and the current node list, this builds the

    environment for the hooks and the target node list for the run.

    """

    if phase == constants.HOOKS_PHASE_PRE:

      prefix = "GANETI_"

    elif phase == constants.HOOKS_PHASE_POST:

      prefix = "GANETI_POST_"

    else:

      raise AssertionError("Unknown phase '%s'" % phase)

    env = {}

    if self.hooks_path is not None:

      phase_env = self.build_env_fn()

      if phase_env:

        assert not compat.any(key.upper().startswith(prefix)

                              for key in phase_env)

        env.update(("%s%s" % (prefix, key), value)

                   for (key, value) in phase_env.items())

    if phase == constants.HOOKS_PHASE_PRE:

      assert compat.all((key.startswith("GANETI_") and

                         not key.startswith("GANETI_POST_"))

                        for key in env)

    elif phase == constants.HOOKS_PHASE_POST:

      assert compat.all(key.startswith("GANETI_POST_") for key in env)

      assert isinstance(self.pre_env, dict)

      # Merge with pre-phase environment

      assert not compat.any(key.startswith("GANETI_POST_")

                            for key in self.pre_env)

      env.update(self.pre_env)

    else:

      raise AssertionError("Unknown phase '%s'" % phase)

    return env

  def _RunWrapper(self, node_list, hpath, phase, phase_env):

    """Simple wrapper over self.callfn.

    This method fixes the environment before executing the hooks.

    """

    env = {

      "PATH": constants.HOOKS_PATH,

      "GANETI_HOOKS_VERSION": constants.HOOKS_VERSION,

      "GANETI_OP_CODE": self.opcode,

      "GANETI_DATA_DIR": pathutils.DATA_DIR,

      "GANETI_HOOKS_PHASE": phase,

      "GANETI_HOOKS_PATH": hpath,

      }

    if self.htype:

      env["GANETI_OBJECT_TYPE"] = self.htype

    if self.cluster_name is not None:

      env["GANETI_CLUSTER"] = self.cluster_name

    if self.master_name is not None:

      env["GANETI_MASTER"] = self.master_name

    if phase_env:

      env = utils.algo.JoinDisjointDicts(env, phase_env)

    # Convert everything to strings

    env = dict([(str(key), str(val)) for key, val in env.iteritems()])

    assert compat.all(key == "PATH" or key.startswith("GANETI_")

                      for key in env)

    return self.hooks_execution_fn(node_list, hpath, phase, env)

  def RunPhase(self, phase, nodes=None):

    """Run all the scripts for a phase.

    This is the main function of the HookMaster.

    It executes self.hooks_execution_fn, and after running

    self.hooks_results_adapt_fn on its results it expects them to be in the form

    {node_name: (fail_msg, [(script, result, output), ...]}).

    @param phase: one of L{constants.HOOKS_PHASE_POST} or

        L{constants.HOOKS_PHASE_PRE}; it denotes the hooks phase

    @param nodes: overrides the predefined list of nodes for the given phase

    @return: the processed results of the hooks multi-node rpc call

    @raise errors.HooksFailure: on communication failure to the nodes

    @raise errors.HooksAbort: on failure of one of the hooks

    """

    if phase == constants.HOOKS_PHASE_PRE:

      if nodes is None:

        nodes = self.pre_nodes

      env = self.pre_env

    elif phase == constants.HOOKS_PHASE_POST:

      if nodes is None:

        nodes = self.post_nodes

      env = self._BuildEnv(phase)

    else:

      raise AssertionError("Unknown phase '%s'" % phase)

    if not nodes:

      # empty node list, we should not attempt to run this as either

      # we're in the cluster init phase and the rpc client part can't

      # even attempt to run, or this LU doesn't do hooks at all

      return

    results = self._RunWrapper(nodes, self.hooks_path, phase, env)

    if not results:

      msg = "Communication Failure"

      if phase == constants.HOOKS_PHASE_PRE:

        raise errors.HooksFailure(msg)

      else:

        self.log_fn(msg)

        return results

    converted_res = results

    if self.hooks_results_adapt_fn:

      converted_res = self.hooks_results_adapt_fn(results)

    errs = []

    for node_name, (fail_msg, offline, hooks_results) in converted_res.items():

      if offline:

        continue

      if fail_msg:

        self.log_fn("Communication failure to node %s: %s", node_name, fail_msg)

        continue

      for script, hkr, output in hooks_results:

        if hkr == constants.HKR_FAIL:

          if phase == constants.HOOKS_PHASE_PRE:

            errs.append((node_name, script, output))

          else:

            if not output:

              output = "(no output)"

            self.log_fn("On %s script %s failed, output: %s" %

                        (node_name, script, output))

    if errs and phase == constants.HOOKS_PHASE_PRE:

      raise errors.HooksAbort(errs)

    return results

  def RunConfigUpdate(self):

    """Run the special configuration update hook

    This is a special hook that runs only on the master after each

    top-level LI if the configuration has been updated.

    """

    phase = constants.HOOKS_PHASE_POST

    hpath = constants.HOOKS_NAME_CFGUPDATE

    nodes = [self.master_name]

    self._RunWrapper(nodes, hpath, phase, self.pre_env)

  @staticmethod

  def BuildFromLu(hooks_execution_fn, lu):

    if lu.HPATH is None:

      nodes = (None, None)

    else:

      nodes = map(frozenset, lu.BuildHooksNodes())

    master_name = cluster_name = None

    if lu.cfg:

      master_name = lu.cfg.GetMasterNode()

      cluster_name = lu.cfg.GetClusterName()

    return HooksMaster(lu.op.OP_ID, lu.HPATH, nodes, hooks_execution_fn,

                       _RpcResultsToHooksResults, lu.BuildHooksEnv,

                       lu.LogWarning, lu.HTYPE, cluster_name, master_name)