taskflow/taskflow/examples/alphabet_soup.py

94 lines
3.2 KiB
Python

# -*- 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 fractions
import functools
import logging
import os
import string
import sys
import time
logging.basicConfig(level=logging.ERROR)
self_dir = os.path.abspath(os.path.dirname(__file__))
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
sys.path.insert(0, self_dir)
from taskflow import engines
from taskflow import exceptions
from taskflow.patterns import linear_flow
from taskflow import task
# In this example we show how a simple linear set of tasks can be executed
# using local processes (and not threads or remote workers) with minimal (if
# any) modification to those tasks to make them safe to run in this mode.
#
# This is useful since it allows further scaling up your workflows when thread
# execution starts to become a bottleneck (which it can start to be due to the
# GIL in python). It also offers a intermediary scalable runner that can be
# used when the scale and/or setup of remote workers is not desirable.
def progress_printer(task, event_type, details):
# This callback, attached to each task will be called in the local
# process (not the child processes)...
progress = details.pop('progress')
progress = int(progress * 100.0)
print("Task '%s' reached %d%% completion" % (task.name, progress))
class AlphabetTask(task.Task):
# Second delay between each progress part.
_DELAY = 0.1
# This task will run in X main stages (each with a different progress
# report that will be delivered back to the running process...). The
# initial 0% and 100% are triggered automatically by the engine when
# a task is started and finished (so that's why those are not emitted
# here).
_PROGRESS_PARTS = [fractions.Fraction("%s/5" % x) for x in range(1, 5)]
def execute(self):
for p in self._PROGRESS_PARTS:
self.update_progress(p)
time.sleep(self._DELAY)
print("Constructing...")
soup = linear_flow.Flow("alphabet-soup")
for letter in string.ascii_lowercase:
abc = AlphabetTask(letter)
abc.notifier.register(task.EVENT_UPDATE_PROGRESS,
functools.partial(progress_printer, abc))
soup.add(abc)
try:
print("Loading...")
e = engines.load(soup, engine='parallel', executor='processes')
print("Compiling...")
e.compile()
print("Preparing...")
e.prepare()
print("Running...")
e.run()
print("Done: %s" % e.statistics)
except exceptions.NotImplementedError as e:
print(e)