114 lines
3.4 KiB
Python
114 lines
3.4 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# Copyright (C) 2014 Ivan Melnikov <iv at altlinux dot org>
|
|
#
|
|
# 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 import task
|
|
|
|
# INTRO: pseudo-scoping by adding prefixes
|
|
|
|
# Sometimes you need scoping -- e.g. for adding several
|
|
# similar subflows to one flow to do same stuff for different
|
|
# data. But current version of TaskFlow does not allow that
|
|
# directly, so you have to resort to some kind of trickery.
|
|
# One (and more or less recommended, if not the only) way of
|
|
# solving the problem is to transform every task name, it's
|
|
# provides and requires values -- e.g. by adding prefix to them.
|
|
# This example shows how this could be done.
|
|
|
|
|
|
# The example task is simple: for each specified person, fetch
|
|
# his or her phone number from phone book and call.
|
|
|
|
|
|
PHONE_BOOK = {
|
|
'jim': '444',
|
|
'joe': '555',
|
|
'iv_m': '666',
|
|
'josh': '777'
|
|
}
|
|
|
|
|
|
class FetchNumberTask(task.Task):
|
|
"""Task that fetches number from phone book."""
|
|
|
|
default_provides = 'number'
|
|
|
|
def execute(self, person):
|
|
print('Fetching number for %s.' % person)
|
|
return PHONE_BOOK[person.lower()]
|
|
|
|
|
|
class CallTask(task.Task):
|
|
"""Task that calls person by number."""
|
|
|
|
def execute(self, person, number):
|
|
print('Calling %s %s.' % (person, number))
|
|
|
|
# This is how it works for one person:
|
|
|
|
simple_flow = lf.Flow('simple one').add(
|
|
FetchNumberTask(),
|
|
CallTask())
|
|
print('Running simple flow:')
|
|
taskflow.engines.run(simple_flow, store={'person': 'Josh'})
|
|
|
|
|
|
# To call several people you'll need a factory function that will
|
|
# make a flow with given prefix for you. We need to add prefix
|
|
# to task names, their provides and requires values. For requires,
|
|
# we use `rebind` argument of task constructor.
|
|
def subflow_factory(prefix):
|
|
def pr(what):
|
|
return '%s-%s' % (prefix, what)
|
|
|
|
return lf.Flow(pr('flow')).add(
|
|
FetchNumberTask(pr('fetch'),
|
|
provides=pr('number'),
|
|
rebind=[pr('person')]),
|
|
CallTask(pr('call'),
|
|
rebind=[pr('person'), pr('number')])
|
|
)
|
|
|
|
|
|
def call_them_all():
|
|
# Let's call them all. We need a flow:
|
|
flow = lf.Flow('call-them-prefixed')
|
|
|
|
# We'll also need to inject person names with prefixed argument
|
|
# name to storage to satisfy task requirements.
|
|
persons = {}
|
|
|
|
for person in ('Jim', 'Joe', 'Josh'):
|
|
prefix = person.lower()
|
|
persons['%s-person' % prefix] = person
|
|
flow.add(subflow_factory(prefix))
|
|
taskflow.engines.run(flow, store=persons)
|
|
|
|
print('\nCalling many people using prefixed factory:')
|
|
call_them_all()
|