blob: f39d7f0effe24aa960fe1a540a12d7e6b7c83ac7 [file] [log] [blame]
#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""API allowing control over some mapreduce implementation details."""
__all__ = ["Hooks"]
class Hooks(object):
"""Allows subclasses to control some aspects of mapreduce execution.
control.start_map accepts an optional "hooks" argument that can be passed a
subclass of this class.
"""
def __init__(self, mapreduce_spec):
"""Initializes a Hooks class.
Args:
mapreduce_spec: The mapreduce.model.MapreduceSpec for the current
mapreduce.
"""
self.mapreduce_spec = mapreduce_spec
def enqueue_worker_task(self, task, queue_name):
"""Enqueues a worker task that is used to run the mapper.
Args:
task: A taskqueue.Task that must be queued in order for the mapreduce
mappers to be run. The task is named.
queue_name: The queue where the task should be run e.g. "default".
Raises:
NotImplementedError: to indicate that the default worker queueing strategy
should be used.
"""
raise NotImplementedError()
def enqueue_kickoff_task(self, task, queue_name):
"""Enqueues a task that is used to start the mapreduce.
This hook will be called within a transaction scope.
Hook should add task transactionally.
Args:
task: A taskqueue.Task that must be queued to run KickOffJobHandler.
queue_name: The queue where the task should be run e.g. "default".
Raises:
NotImplementedError: to indicate that the default mapreduce start strategy
should be used.
"""
raise NotImplementedError()
def enqueue_done_task(self, task, queue_name):
"""Enqueues a task that is triggered when the mapreduce completes.
This hook will be called within a transaction scope.
Hook should add task transactionally.
Args:
task: A taskqueue.Task that must be queued in order for the client to be
notified when the mapreduce is complete.
queue_name: The queue where the task should be run e.g. "default".
Raises:
NotImplementedError: to indicate that the default mapreduce notification
strategy should be used.
"""
raise NotImplementedError()
def enqueue_controller_task(self, task, queue_name):
"""Enqueues a task that is used to monitor the mapreduce process.
Args:
task: A taskqueue.Task that must be queued in order for updates to the
mapreduce process to be properly tracked. The task is named.
queue_name: The queue where the task should be run e.g. "default".
Raises:
NotImplementedError: to indicate that the default mapreduce tracking
strategy should be used.
"""
raise NotImplementedError()