openstack/deb-python-taskflow
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deb-python-taskflow/taskflow/examples/99_bottles.py
Joshua Harlow 7f84bf6e03 99 bottles example trace logging was not being output 
When 'v' was provided as a last argument trace
logging is supposed to be enabled, but it seems like
due to the prior configuration of ERROR level it was not
so this fixes that and only configures the ERROR level
if verbose argument is not present.

Change-Id: I527ab1868e4eb5544e0f502e655ba8fcc5913014
2016-01-20 12:32:24 -08:00

243 lines
8.7 KiB
Python
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# -*- coding: utf-8 -*-
# Copyright (C) 2015 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 contextlib
import functools
import logging
import os
import sys
import time
import traceback
from kazoo import client
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
from taskflow.conductors import backends as conductor_backends
from taskflow import engines
from taskflow.jobs import backends as job_backends
from taskflow import logging as taskflow_logging
from taskflow.patterns import linear_flow as lf
from taskflow.persistence import backends as persistence_backends
from taskflow.persistence import logbook
from taskflow import task
from taskflow.types import timing
from oslo_utils import uuidutils
# Instructions!
#
# 1. Install zookeeper (or change host listed below)
# 2. Download this example, place in file '99_bottles.py'
# 3. Run `python 99_bottles.py p` to place a song request onto the jobboard
# 4. Run `python 99_bottles.py c` a few times (in different shells)
# 5. On demand kill previously listed processes created in (4) and watch
# the work resume on another process (and repeat)
# 6. Keep enough workers alive to eventually finish the song (if desired).
ME = os.getpid()
ZK_HOST = "localhost:2181"
JB_CONF = {
'hosts': ZK_HOST,
'board': 'zookeeper',
'path': '/taskflow/99-bottles-demo',
}
PERSISTENCE_URI = r"sqlite:////tmp/bottles.db"
TAKE_DOWN_DELAY = 1.0
PASS_AROUND_DELAY = 3.0
HOW_MANY_BOTTLES = 99
class TakeABottleDown(task.Task):
def execute(self, bottles_left):
sys.stdout.write('Take one down, ')
sys.stdout.flush()
time.sleep(TAKE_DOWN_DELAY)
return bottles_left - 1
class PassItAround(task.Task):
def execute(self):
sys.stdout.write('pass it around, ')
sys.stdout.flush()
time.sleep(PASS_AROUND_DELAY)
class Conclusion(task.Task):
def execute(self, bottles_left):
sys.stdout.write('%s bottles of beer on the wall...\n' % bottles_left)
sys.stdout.flush()
def make_bottles(count):
# This is the function that will be called to generate the workflow
# and will also be called to regenerate it on resumption so that work
# can continue from where it last left off...
s = lf.Flow("bottle-song")
take_bottle = TakeABottleDown("take-bottle-%s" % count,
inject={'bottles_left': count},
provides='bottles_left')
pass_it = PassItAround("pass-%s-around" % count)
next_bottles = Conclusion("next-bottles-%s" % (count - 1))
s.add(take_bottle, pass_it, next_bottles)
for bottle in reversed(list(range(1, count))):
take_bottle = TakeABottleDown("take-bottle-%s" % bottle,
provides='bottles_left')
pass_it = PassItAround("pass-%s-around" % bottle)
next_bottles = Conclusion("next-bottles-%s" % (bottle - 1))
s.add(take_bottle, pass_it, next_bottles)
return s
def run_conductor(only_run_once=False):
# This continuously consumers until its stopped via ctrl-c or other
# kill signal...
event_watches = {}
# This will be triggered by the conductor doing various activities
# with engines, and is quite nice to be able to see the various timing
# segments (which is useful for debugging, or watching, or figuring out
# where to optimize).
def on_conductor_event(cond, event, details):
print("Event '%s' has been received..." % event)
print("Details = %s" % details)
if event.endswith("_start"):
w = timing.StopWatch()
w.start()
base_event = event[0:-len("_start")]
event_watches[base_event] = w
if event.endswith("_end"):
base_event = event[0:-len("_end")]
try:
w = event_watches.pop(base_event)
w.stop()
print("It took %0.3f seconds for event '%s' to finish"
% (w.elapsed(), base_event))
except KeyError:
pass
if event == 'running_end' and only_run_once:
cond.stop()
print("Starting conductor with pid: %s" % ME)
my_name = "conductor-%s" % ME
persist_backend = persistence_backends.fetch(PERSISTENCE_URI)
with contextlib.closing(persist_backend):
with contextlib.closing(persist_backend.get_connection()) as conn:
conn.upgrade()
job_backend = job_backends.fetch(my_name, JB_CONF,
persistence=persist_backend)
job_backend.connect()
with contextlib.closing(job_backend):
cond = conductor_backends.fetch('blocking', my_name, job_backend,
persistence=persist_backend)
on_conductor_event = functools.partial(on_conductor_event, cond)
cond.notifier.register(cond.notifier.ANY, on_conductor_event)
# Run forever, and kill -9 or ctrl-c me...
try:
cond.run()
finally:
cond.stop()
cond.wait()
def run_poster():
# This just posts a single job and then ends...
print("Starting poster with pid: %s" % ME)
my_name = "poster-%s" % ME
persist_backend = persistence_backends.fetch(PERSISTENCE_URI)
with contextlib.closing(persist_backend):
with contextlib.closing(persist_backend.get_connection()) as conn:
conn.upgrade()
job_backend = job_backends.fetch(my_name, JB_CONF,
persistence=persist_backend)
job_backend.connect()
with contextlib.closing(job_backend):
# Create information in the persistence backend about the
# unit of work we want to complete and the factory that
# can be called to create the tasks that the work unit needs
# to be done.
lb = logbook.LogBook("post-from-%s" % my_name)
fd = logbook.FlowDetail("song-from-%s" % my_name,
uuidutils.generate_uuid())
lb.add(fd)
with contextlib.closing(persist_backend.get_connection()) as conn:
conn.save_logbook(lb)
engines.save_factory_details(fd, make_bottles,
[HOW_MANY_BOTTLES], {},
backend=persist_backend)
# Post, and be done with it!
jb = job_backend.post("song-from-%s" % my_name, book=lb)
print("Posted: %s" % jb)
print("Goodbye...")
def main_local():
# Run locally typically this is activating during unit testing when all
# the examples are made sure to still function correctly...
global TAKE_DOWN_DELAY
global PASS_AROUND_DELAY
global JB_CONF
# Make everything go much faster (so that this finishes quickly).
PASS_AROUND_DELAY = 0.01
TAKE_DOWN_DELAY = 0.01
JB_CONF['path'] = JB_CONF['path'] + "-" + uuidutils.generate_uuid()
run_poster()
run_conductor(only_run_once=True)
def check_for_zookeeper(timeout=1):
sys.stderr.write("Testing for the existence of a zookeeper server...\n")
sys.stderr.write("Please wait....\n")
with contextlib.closing(client.KazooClient()) as test_client:
try:
test_client.start(timeout=timeout)
except test_client.handler.timeout_exception:
sys.stderr.write("Zookeeper is needed for running this example!\n")
traceback.print_exc()
return False
else:
test_client.stop()
return True
def main():
if not check_for_zookeeper():
return
if len(sys.argv) == 1:
main_local()
elif sys.argv[1] in ('p', 'c'):
if sys.argv[-1] == "v":
logging.basicConfig(level=taskflow_logging.TRACE)
else:
logging.basicConfig(level=logging.ERROR)
if sys.argv[1] == 'p':
run_poster()
else:
run_conductor()
else:
sys.stderr.write("%s p|c (v?)\n" % os.path.basename(sys.argv[0]))
if __name__ == '__main__':
main()
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