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import logging
import os
import sys
logging.basicConfig(level=logging.ERROR)
top_dir = os.path.abspath(os.path.join(os.path.dirname(__file__),
os.pardir,
os.pardir))
sys.path.insert(0, top_dir)
import taskflow.engines
from taskflow.patterns import linear_flow as lf
from taskflow import task
# In this example LinearFlow is used to group four tasks to
# calculate value. Added task is used twice. In the first case
# it uses default parameters ('x' and 'y') and in the second one
# arguments are binding with 'z' and 'd' keys from engine storage.
# Multiplier task uses binding too, but explicitly shows that 'z'
# parameter is binded with 'a' key from engine storage.
class Provider(task.Task):
def __init__(self, name, *args, **kwargs):
super(Provider, self).__init__(name=name, **kwargs)
self._provide = args
def execute(self):
return self._provide
class Adder(task.Task):
def __init__(self, name, provides=None, rebind=None):
super(Adder, self).__init__(name=name, provides=provides,
rebind=rebind)
def execute(self, x, y):
return x + y
class Multiplier(task.Task):
def __init__(self, name, multiplier, provides=None, rebind=None):
super(Multiplier, self).__init__(name=name, provides=provides,
rebind=rebind)
self._multiplier = multiplier
def execute(self, z):
return z * self._multiplier
flow = lf.Flow('root').add(
# x = 2, y = 3, d = 5
Provider("provide-adder", 2, 3, 5, provides=('x', 'y', 'd')),
# z = x+y = 5
Adder("add-1", provides='z'),
# a = z+d = 10
Adder("add-2", provides='a', rebind=['z', 'd']),
# r = a*3 = 30
Multiplier("multi", 3, provides='r', rebind={'z': 'a'})
)
results = taskflow.engines.run(flow)
print results
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