88898570ad
When this is ran without any arguments just run it locally by starting a producer, then a conductor, then stopping after it finishes the first song request. This allows this example to be ran during unit testing to make sure it functions as expected (with zero return code). Change-Id: I26c210e2c993e770955985c9c779d303eb8c0616
222 lines
8.0 KiB
Python
222 lines
8.0 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import contextlib
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import functools
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import logging
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import os
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import sys
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import time
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top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
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os.pardir,
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os.pardir))
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sys.path.insert(0, top_dir)
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from taskflow.conductors import backends as conductor_backends
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from taskflow import engines
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from taskflow.jobs import backends as job_backends
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from taskflow.patterns import linear_flow as lf
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from taskflow.persistence import backends as persistence_backends
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from taskflow.persistence import logbook
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from taskflow import task
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from taskflow.types import timing
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from oslo_utils import uuidutils
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# Instructions!
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#
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# 1. Install zookeeper (or change host listed below)
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# 2. Download this example, place in file '99_bottles.py'
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# 3. Run `python 99_bottles.py p` to place a song request onto the jobboard
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# 4. Run `python 99_bottles.py c` a few times (in different shells)
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# 5. On demand kill previously listed processes created in (4) and watch
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# the work resume on another process (and repeat)
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# 6. Keep enough workers alive to eventually finish the song (if desired).
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ME = os.getpid()
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ZK_HOST = "localhost:2181"
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JB_CONF = {
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'hosts': ZK_HOST,
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'board': 'zookeeper',
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'path': '/taskflow/99-bottles-demo',
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}
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PERSISTENCE_URI = r"sqlite:////tmp/bottles.db"
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TAKE_DOWN_DELAY = 1.0
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PASS_AROUND_DELAY = 3.0
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HOW_MANY_BOTTLES = 99
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class TakeABottleDown(task.Task):
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def execute(self, bottles_left):
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sys.stdout.write('Take one down, ')
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sys.stdout.flush()
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time.sleep(TAKE_DOWN_DELAY)
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return bottles_left - 1
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class PassItAround(task.Task):
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def execute(self):
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sys.stdout.write('pass it around, ')
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sys.stdout.flush()
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time.sleep(PASS_AROUND_DELAY)
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class Conclusion(task.Task):
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def execute(self, bottles_left):
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sys.stdout.write('%s bottles of beer on the wall...\n' % bottles_left)
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sys.stdout.flush()
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def make_bottles(count):
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# This is the function that will be called to generate the workflow
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# and will also be called to regenerate it on resumption so that work
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# can continue from where it last left off...
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s = lf.Flow("bottle-song")
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take_bottle = TakeABottleDown("take-bottle-%s" % count,
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inject={'bottles_left': count},
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provides='bottles_left')
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pass_it = PassItAround("pass-%s-around" % count)
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next_bottles = Conclusion("next-bottles-%s" % (count - 1))
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s.add(take_bottle, pass_it, next_bottles)
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for bottle in reversed(list(range(1, count))):
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take_bottle = TakeABottleDown("take-bottle-%s" % bottle,
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provides='bottles_left')
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pass_it = PassItAround("pass-%s-around" % bottle)
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next_bottles = Conclusion("next-bottles-%s" % (bottle - 1))
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s.add(take_bottle, pass_it, next_bottles)
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return s
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def run_conductor(only_run_once=False):
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# This continuously consumers until its stopped via ctrl-c or other
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# kill signal...
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event_watches = {}
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# This will be triggered by the conductor doing various activities
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# with engines, and is quite nice to be able to see the various timing
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# segments (which is useful for debugging, or watching, or figuring out
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# where to optimize).
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def on_conductor_event(cond, event, details):
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print("Event '%s' has been received..." % event)
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print("Details = %s" % details)
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if event.endswith("_start"):
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w = timing.StopWatch()
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w.start()
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base_event = event[0:-len("_start")]
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event_watches[base_event] = w
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if event.endswith("_end"):
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base_event = event[0:-len("_end")]
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try:
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w = event_watches.pop(base_event)
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w.stop()
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print("It took %0.3f seconds for event '%s' to finish"
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% (w.elapsed(), base_event))
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except KeyError:
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pass
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if event == 'running_end' and only_run_once:
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cond.stop()
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print("Starting conductor with pid: %s" % ME)
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my_name = "conductor-%s" % ME
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persist_backend = persistence_backends.fetch(PERSISTENCE_URI)
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with contextlib.closing(persist_backend):
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with contextlib.closing(persist_backend.get_connection()) as conn:
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conn.upgrade()
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job_backend = job_backends.fetch(my_name, JB_CONF,
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persistence=persist_backend)
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job_backend.connect()
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with contextlib.closing(job_backend):
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cond = conductor_backends.fetch('blocking', my_name, job_backend,
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persistence=persist_backend)
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on_conductor_event = functools.partial(on_conductor_event, cond)
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cond.notifier.register(cond.notifier.ANY, on_conductor_event)
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# Run forever, and kill -9 or ctrl-c me...
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try:
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cond.run()
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finally:
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cond.stop()
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cond.wait()
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def run_poster():
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# This just posts a single job and then ends...
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print("Starting poster with pid: %s" % ME)
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my_name = "poster-%s" % ME
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persist_backend = persistence_backends.fetch(PERSISTENCE_URI)
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with contextlib.closing(persist_backend):
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with contextlib.closing(persist_backend.get_connection()) as conn:
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conn.upgrade()
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job_backend = job_backends.fetch(my_name, JB_CONF,
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persistence=persist_backend)
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job_backend.connect()
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with contextlib.closing(job_backend):
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# Create information in the persistence backend about the
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# unit of work we want to complete and the factory that
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# can be called to create the tasks that the work unit needs
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# to be done.
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lb = logbook.LogBook("post-from-%s" % my_name)
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fd = logbook.FlowDetail("song-from-%s" % my_name,
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uuidutils.generate_uuid())
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lb.add(fd)
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with contextlib.closing(persist_backend.get_connection()) as conn:
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conn.save_logbook(lb)
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engines.save_factory_details(fd, make_bottles,
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[HOW_MANY_BOTTLES], {},
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backend=persist_backend)
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# Post, and be done with it!
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jb = job_backend.post("song-from-%s" % my_name, book=lb)
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print("Posted: %s" % jb)
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print("Goodbye...")
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def main_local():
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# Run locally typically this is activating during unit testing when all
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# the examples are made sure to still function correctly...
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global TAKE_DOWN_DELAY
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global PASS_AROUND_DELAY
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global JB_CONF
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# Make everything go much faster (so that this finishes quickly).
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PASS_AROUND_DELAY = 0.01
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TAKE_DOWN_DELAY = 0.01
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JB_CONF['path'] = JB_CONF['path'] + "-" + uuidutils.generate_uuid()
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run_poster()
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run_conductor(only_run_once=True)
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def main():
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if len(sys.argv) == 1:
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main_local()
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elif sys.argv[1] in ('p', 'c'):
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if sys.argv[-1] == "v":
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logging.basicConfig(level=5)
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else:
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logging.basicConfig(level=logging.ERROR)
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if sys.argv[1] == 'p':
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run_poster()
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else:
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run_conductor()
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else:
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sys.stderr.write("%s p|c (v?)\n" % os.path.basename(sys.argv[0]))
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if __name__ == '__main__':
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main()
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