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# -*- coding: utf-8 -*-
# Copyright (C) 2014 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)
from taskflow import engines
from taskflow.patterns import linear_flow as lf
from taskflow.patterns import unordered_flow as uf
from taskflow import task
# INTRO: This is the defacto hello world equivalent for taskflow; it shows how
# an overly simplistic workflow can be created that runs using different
# engines using different styles of execution (all can be used to run in
# parallel if a workflow is provided that is parallelizable).
class PrinterTask(task.Task):
def __init__(self, name, show_name=True, inject=None):
super(PrinterTask, self).__init__(name, inject=inject)
self._show_name = show_name
def execute(self, output):
if self._show_name:
print("%s: %s" % (self.name, output))
else:
print(output)
# This will be the work that we want done, which for this example is just to
# print 'hello world' (like a song) using different tasks and different
# execution models.
song = lf.Flow("beats")
# Unordered flows when ran can be ran in parallel; and a chorus is everyone
# singing at once of course!
hi_chorus = uf.Flow('hello')
world_chorus = uf.Flow('world')
for (name, hello, world) in [('bob', 'hello', 'world'),
('joe', 'hellooo', 'worllllld'),
('sue', "helloooooo!", 'wooorllld!')]:
hi_chorus.add(PrinterTask("%s@hello" % name,
# This will show up to the execute() method of
# the task as the argument named 'output' (which
# will allow us to print the character we want).
inject={'output': hello}))
world_chorus.add(PrinterTask("%s@world" % name,
inject={'output': world}))
# The composition starts with the conductor and then runs in sequence with
# the chorus running in parallel, but no matter what the 'hello' chorus must
# always run before the 'world' chorus (otherwise the world will fall apart).
song.add(PrinterTask("conductor@begin",
show_name=False, inject={'output': "*ding*"}),
hi_chorus,
world_chorus,
PrinterTask("conductor@end",
show_name=False, inject={'output': "*dong*"}))
# Run in parallel using eventlet green threads...
try:
import eventlet as _eventlet # noqa
except ImportError:
# No eventlet currently active, skip running with it...
pass
else:
print("-- Running in parallel using eventlet --")
e = engines.load(song, executor='greenthreaded', engine='parallel',
max_workers=1)
e.run()
# Run in parallel using real threads...
print("-- Running in parallel using threads --")
e = engines.load(song, executor='threaded', engine='parallel',
max_workers=1)
e.run()
# Run in parallel using external processes...
print("-- Running in parallel using processes --")
e = engines.load(song, executor='processes', engine='parallel',
max_workers=1)
e.run()
# Run serially (aka, if the workflow could have been ran in parallel, it will
# not be when ran in this mode)...
print("-- Running serially --")
e = engines.load(song, engine='serial')
e.run()
print("-- Statistics gathered --")
print(e.statistics)
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