63c6730248
When a conductor is running it is quite useful to be able to how long each engine step takes. To enable this information being output, add a notifier to the base conductor and use it in the blocking conductor to emit events around engine activities. This makes it possible to track the timing (or other information that can be gathered from these events) in a non-intrusive manner. In the `99_bottles.py` demo we also now use this to be able to easily see what the conductor is actively doing (without having to enable the more verbose DEBUG level logging). Change-Id: Ifd8ff38f82fc8135fe5fec4c8e41f0e06f4fdee3
192 lines
6.8 KiB
Python
192 lines
6.8 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 logging
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import os
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import sys
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import time
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logging.basicConfig(level=logging.ERROR)
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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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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():
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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(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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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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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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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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job_backend.post("song-from-%s" % my_name, book=lb)
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def main():
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if len(sys.argv) == 1:
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sys.stderr.write("%s p|c\n" % os.path.basename(sys.argv[0]))
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elif sys.argv[1] == 'p':
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run_poster()
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elif sys.argv[1] == 'c':
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run_conductor()
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else:
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sys.stderr.write("%s p|c\n" % os.path.basename(sys.argv[0]))
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if __name__ == '__main__':
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main()
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