Previously to run a flow client code had to put together the flow,
an engine, logbook, flowdetail, and storage backend. This commit
adds two helper functions, run() and load(), so that simplest usecase
now looks like
taskflow.engines.run(flow)
Client code may also provide configuration for storage and engine if
needed, but if not needed it just works with defaults.
Engines are loaded via stevedore, as drivers in 'taskflow.engines'
backend. Now three entry points are defined in that namespace:
- 'default', for SingleThreadedActionEngine, used by default;
- 'serial', as another synonym for SingleThreadedActionEngine;
- 'parallel', for MultiThreadedActionEngine.
Closes-bug: #1224726
Change-Id: I7f4cb5c8ff7f5f12831ddd0952c202d2fd8cd6ef
130 lines
3.1 KiB
Python
130 lines
3.1 KiB
Python
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import logging
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import os
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import sys
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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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import taskflow.engines
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from taskflow.patterns import graph_flow as gf
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from taskflow.patterns import linear_flow as lf
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from taskflow import task
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def build_frame():
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return 'steel'
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def build_engine():
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return 'honda'
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def build_doors():
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return '2'
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def build_wheels():
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return '4'
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def install_engine(frame, engine):
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return True
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def install_doors(frame, windows_installed, doors):
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return True
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def install_windows(frame, doors):
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return True
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def install_wheels(frame, engine, engine_installed, wheels):
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return True
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def trash(**kwargs):
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print("Throwing away pieces of car!")
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def startup(**kwargs):
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# TODO(harlowja): try triggering reversion here!
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# raise ValueError("Car not verified")
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return True
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def verify(spec, **kwargs):
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for key, value in kwargs.items():
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if spec[key] != value:
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raise Exception("Car doesn't match spec!")
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return True
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def flow_watch(state, details):
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print('Flow => %s' % state)
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def task_watch(state, details):
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print('Task %s => %s' % (details.get('task_name'), state))
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flow = lf.Flow("make-auto").add(
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task.FunctorTask(startup, revert=trash, provides='ran'),
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gf.Flow("install-parts").add(
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task.FunctorTask(build_frame, provides='frame'),
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task.FunctorTask(build_engine, provides='engine'),
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task.FunctorTask(build_doors, provides='doors'),
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task.FunctorTask(build_wheels, provides='wheels'),
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task.FunctorTask(install_engine, provides='engine_installed'),
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task.FunctorTask(install_doors, provides='doors_installed'),
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task.FunctorTask(install_windows, provides='windows_installed'),
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task.FunctorTask(install_wheels, provides='wheels_installed')),
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task.FunctorTask(verify, requires=['frame',
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'engine',
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'doors',
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'wheels',
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'engine_installed',
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'doors_installed',
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'windows_installed',
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'wheels_installed']))
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spec = {
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"frame": 'steel',
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"engine": 'honda',
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"doors": '2',
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"wheels": '4',
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"engine_installed": True,
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"doors_installed": True,
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"windows_installed": True,
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"wheels_installed": True,
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}
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engine = taskflow.engines.load(flow, store={'spec': spec.copy()})
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engine.notifier.register('*', flow_watch)
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engine.task_notifier.register('*', task_watch)
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print("Build a car")
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engine.run()
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spec['doors'] = 5
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engine = taskflow.engines.load(flow, store={'spec': spec.copy()})
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engine.notifier.register('*', flow_watch)
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engine.task_notifier.register('*', task_watch)
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try:
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print("Build a wrong car that doesn't match specification")
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engine.run()
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except Exception as e:
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print("Flow failed: %s" % e)
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