How to implement retry mechanism into Python Requests library?

Question

I would like to add a retry mechanism to Python Requests library, so scripts that are using it will retry for non-fatal errors. At this moment I do consider three kind of errors to be recoverable: - HTTP return codes 502, 503, 504 - host not found (less important now) - request timeout At the first stage I do want to retry specified 5xx requests every minute. I want to be able to add this functionality transparently, without having to manually implement recovery for each HTTP call made from inside these scripts or libraries that are using Python Requests.

Accepted Answer

I was able to obtain the desired level of reliability by extending `requests.Session` class.

Here is the code https://bitbucket.org/bspeakmon/jira-python/src/a7fca855394402f58507ca4056de87ccdbd6a213/jira/resilientsession.py?at=master

EDIT That code was:

```
from requests import Session
from requests.exceptions import ConnectionError
import logging
import time

class ResilientSession(Session):

"""
    This class is supposed to retry requests that do return temporary errors.

At this moment it supports: 502, 503, 504
    """

def __recoverable(self, error, url, request, counter=1):
        if hasattr(error,'status_code'):
            if error.status_code in [502, 503, 504]:
                error = "HTTP %s" % error.status_code
            else:
                return False
        DELAY = 10 * counter
        logging.warn("Got recoverable error [%s] from %s %s, retry #%s in %ss" % (error, request, url, counter, DELAY))
        time.sleep(DELAY)
        return True

def get(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).get(url, **kwargs)
            except ConnectionError as e:
                r = e.message
            if self.__recoverable(r, url, 'GET', counter):
                continue
            return r

def post(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).post(url, **kwargs)
            except ConnectionError as e:
                r = e.message
            if self.__recoverable(r, url, 'POST', counter):
                continue
            return r

def delete(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).delete(url, **kwargs)
            except ConnectionError as e:
                r = e.message
            if self.__recoverable(r, url, 'DELETE', counter):
                continue
            return r

def put(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).put(url, **kwargs)
            except ConnectionError as e:
                r = e.message

if self.__recoverable(r, url, 'PUT', counter):
                continue
            return r

def head(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).head(url, **kwargs)
            except ConnectionError as e:
                r = e.message
            if self.__recoverable(r, url, 'HEAD', counter):
                continue
            return r

def patch(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).patch(url, **kwargs)
            except ConnectionError as e:
                r = e.message

if self.__recoverable(r, url, 'PATCH', counter):
                continue
            return r

def options(self, url, **kwargs):
        counter = 0
        while True:
            counter += 1
            try:
                r = super(ResilientSession, self).options(url, **kwargs)
            except ConnectionError as e:
                r = e.message

if self.__recoverable(r, url, 'OPTIONS', counter):
                continue
            return r
```

How to implement retry mechanism into Python Requests library?

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