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Use an existing python decorator with variable parameters
#
# pip install tenacity
# Usage:
# → py variable-python-decorators.py 4
# The given maximum attempt number is 4
# We want this function to be retried 5 times
# We want this function to be retried 5 times
# We want this function to be retried 5 times
# We want this function to be retried 5 times
# We want this function to be retried 5 times
# The function was retried 5 times.
# We want this function to be retried only 4 times
# We want this function to be retried only 4 times
# We want this function to be retried only 4 times
# We want this function to be retried only 4 times
# The function was retried 4 times.
#
import sys
from tenacity import retry, stop_after_attempt
# Typically, if the decorators you use are customisable, you
# have to pass parameters in the decorator like this:
max_attempts = 5
@retry(stop=stop_after_attempt(max_attempts))
def constant_decoration():
print "We want this function to be retried {} times".format(max_attempts)
raise Exception("Exception thrown to trigger retry")
def static_decorator():
try:
constant_decoration()
except:
print "The function was retried {} times.".format(max_attempts)
# To obtain a behavior that is variable based on runtime given arguments
# or maybe configuration, you can enhance the decorator like this:
#
# Create your own decarator that forward the call to the underlying decorator
# with the arguments you want
def variable_retry(func):
def _retry(*args):
if args.count > 0:
def call():
func(*args)
variable_max_attempt = int(args[0])
return apply(retry(stop=stop_after_attempt(variable_max_attempt))(call))
else:
return func(*args)
return _retry
# Use your new decorator
@variable_retry
def variable_decoration(given_max_attempts):
print "We want this function to be retried only {} times".format(given_max_attempts)
raise Exception("Exception thrown to trigger retry")
def variable_decorator(given_max_attempts):
try:
variable_decoration(given_max_attempts)
except:
print "The function was retried {} times.".format(given_max_attempts)
def main(args):
given_max_attempts = args[1]
print "The given maximum attempt number is {}".format(given_max_attempts)
static_decorator()
variable_decorator(given_max_attempts)
if __name__ == "__main__":
main(sys.argv)
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