Files
deb-python-taskflow/taskflow/examples/calculate_in_parallel.py
Joshua Harlow d433a5323f Deprecate engine_conf and prefer engine instead
To avoid having one set of options coming from `engine_conf`
and another set of options coming from `kwargs` and another set
coming from `engine_conf` if it is a URI just start to shift
toward `engine_conf` being deprecated and `engine` being a string
type only (or a URI with additional query parameters) and having
any additional **kwargs that are provided just get merged into the
final engine options.

This adds a new helper function that handles all these various
options and adds in a keyword argument `engine` that will be shifted
to in a future version (in that future version we can also then
remove the `engine_conf` and just stick to a smaller set of option
mechanisms).

It also adjusts all examples to use this new and more easier to
understand format and adjusts tests, conductor interface to use
this new more easily understandable style of getting an engine.

Change-Id: Ic7617057338e0c63775cf38a24643cff6e454950
2014-10-18 13:28:27 -07:00

98 lines
3.8 KiB
Python

# -*- coding: utf-8 -*-
# Copyright (C) 2012-2013 Yahoo! Inc. All Rights Reserved.
#
# 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.
import logging
import os
import sys
logging.basicConfig(level=logging.ERROR)
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
import taskflow.engines
from taskflow.patterns import linear_flow as lf
from taskflow.patterns import unordered_flow as uf
from taskflow import task
# INTRO: This examples shows how a linear flow and a unordered flow can be
# used together to execute calculations in parallel and then use the
# result for the next task/s. The adder task is used for all calculations
# and argument bindings are used to set correct parameters for each task.
# This task provides some values from as a result of execution, this can be
# useful when you want to provide values from a static set to other tasks that
# depend on those values existing before those tasks can run.
#
# NOTE(harlowja): this usage is *depreciated* in favor of a simpler mechanism
# that provides those values on engine running by prepopulating the storage
# backend before your tasks are ran (which accomplishes a similar goal in a
# more uniform manner).
class Provider(task.Task):
def __init__(self, name, *args, **kwargs):
super(Provider, self).__init__(name=name, **kwargs)
self._provide = args
def execute(self):
return self._provide
# This task adds two input variables and returns the result of that addition.
#
# Note that since this task does not have a revert() function (since addition
# is a stateless operation) there are no side-effects that this function needs
# to undo if some later operation fails.
class Adder(task.Task):
def execute(self, x, y):
return x + y
flow = lf.Flow('root').add(
# Provide the initial values for other tasks to depend on.
#
# x1 = 2, y1 = 3, x2 = 5, x3 = 8
Provider("provide-adder", 2, 3, 5, 8,
provides=('x1', 'y1', 'x2', 'y2')),
# Note here that we define the flow that contains the 2 adders to be an
# unordered flow since the order in which these execute does not matter,
# another way to solve this would be to use a graph_flow pattern, which
# also can run in parallel (since they have no ordering dependencies).
uf.Flow('adders').add(
# Calculate 'z1 = x1+y1 = 5'
#
# Rebind here means that the execute() function x argument will be
# satisfied from a previous output named 'x1', and the y argument
# of execute() will be populated from the previous output named 'y1'
#
# The output (result of adding) will be mapped into a variable named
# 'z1' which can then be refereed to and depended on by other tasks.
Adder(name="add", provides='z1', rebind=['x1', 'y1']),
# z2 = x2+y2 = 13
Adder(name="add-2", provides='z2', rebind=['x2', 'y2']),
),
# r = z1+z2 = 18
Adder(name="sum-1", provides='r', rebind=['z1', 'z2']))
# The result here will be all results (from all tasks) which is stored in an
# in-memory storage location that backs this engine since it is not configured
# with persistence storage.
result = taskflow.engines.run(flow, engine='parallel')
print(result)