cde0dee14e
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
68 lines
1.9 KiB
Python
68 lines
1.9 KiB
Python
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 linear_flow as lf
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from taskflow import task
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# In this example LinearFlow is used to group four tasks to
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# calculate value. Added task is used twice. In the first case
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# it uses default parameters ('x' and 'y') and in the second one
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# arguments are binding with 'z' and 'd' keys from engine storage.
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# Multiplier task uses binding too, but explicitly shows that 'z'
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# parameter is binded with 'a' key from engine storage.
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class Provider(task.Task):
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def __init__(self, name, *args, **kwargs):
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super(Provider, self).__init__(name=name, **kwargs)
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self._provide = args
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def execute(self):
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return self._provide
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class Adder(task.Task):
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def __init__(self, name, provides=None, rebind=None):
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super(Adder, self).__init__(name=name, provides=provides,
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rebind=rebind)
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def execute(self, x, y):
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return x + y
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class Multiplier(task.Task):
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def __init__(self, name, multiplier, provides=None, rebind=None):
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super(Multiplier, self).__init__(name=name, provides=provides,
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rebind=rebind)
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self._multiplier = multiplier
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def execute(self, z):
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return z * self._multiplier
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flow = lf.Flow('root').add(
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# x = 2, y = 3, d = 5
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Provider("provide-adder", 2, 3, 5, provides=('x', 'y', 'd')),
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# z = x+y = 5
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Adder("add-1", provides='z'),
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# a = z+d = 10
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Adder("add-2", provides='a', rebind=['z', 'd']),
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# r = a*3 = 30
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Multiplier("multi", 3, provides='r', rebind={'z': 'a'})
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)
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results = taskflow.engines.run(flow)
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print results
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