Pythonic way of retry running a function
exception, python
Solution
Define retry utility:
# Retry utility
# set logging for `retry` channel
import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger('retry')
# Define Exception class for retry
class RetryException(Exception):
u_str = "Exception ({}) raised after {} tries."
def __init__(self, exp, max_retry):
self.exp = exp
self.max_retry = max_retry
def __unicode__(self):
return self.u_str.format(self.exp, self.max_retry)
def __str__(self):
return self.__unicode__()
# Define retry util function
def retry_func(func, max_retry=10):
"""
@param func: The function that needs to be retry
@param max_retry: Maximum retry of `func` function, default is `10`
@return: func
@raise: RetryException if retries exceeded than max_retry
"""
for retry in range(1, max_retry + 1):
try:
return func()
except Exception, e:
logger.info('Failed to call {}, in retry({}/{})'.format(func.func,
retry, max_retry))
else:
raise RetryException(e, max_retry)
Use it:
from functools import partial
import requests
def some_request(uri, post):
req = requests.post(uri, post)
return req
uri = 'http://someuri.com'
post = {'test': 'yes'}
try:
retry_func(partial(some_request, uri, post), max_retry=3)
except RetryException, e:
print(e)
Output:
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): someuri.com
INFO:retry:Failed to call <function some_request at 0x7faaba2318c0>, in retry(1/3)
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): someuri.com
INFO:retry:Failed to call <function some_request at 0x7faaba2318c0>, in retry(2/3)
INFO:requests.packages.urllib3.connectionpool:Starting new HTTP connection (1): someuri.com
INFO:retry:Failed to call <function some_request at 0x7faaba2318c0>, in retry(3/3)
Exception (HTTPConnectionPool(host='someuri.com', port=80): Max retries exceeded with url: / (Caused by <class 'socket.gaierror'>: [Errno -2] Name or service not known)) raised after 3 tries.
Problem
How a Python Professinal would retry running a function that will request a web service(the webservice sometimes fails) The function: ``` def some_request(uri): try: req = requests.post('http://someuri.com', {'test': 'yes'}) except Exception as e: return False return {'id': req.json()['value'], 'other': req.json()['other']} ``` You handle the retry with a while or other python idiom? Give me a clue on how to do it the right way.