packages.urllib3.util.retry

Module Contents

Classes

Retry(self,total=10,connect=None,read=None,redirect=None,method_whitelist=DEFAULT_METHOD_WHITELIST,status_forcelist=None,backoff_factor=0,raise_on_redirect=True,_observed_errors=0) Retry configuration.
class Retry(total=10, connect=None, read=None, redirect=None, method_whitelist=DEFAULT_METHOD_WHITELIST, status_forcelist=None, backoff_factor=0, raise_on_redirect=True, _observed_errors=0)

Retry configuration.

Each retry attempt will create a new Retry object with updated values, so they can be safely reused.

Retries can be defined as a default for a pool:

retries = Retry(connect=5, read=2, redirect=5)
http = PoolManager(retries=retries)
response = http.request('GET', 'http://example.com/')

Or per-request (which overrides the default for the pool):

response = http.request('GET', 'http://example.com/', retries=Retry(10))

Retries can be disabled by passing False:

response = http.request('GET', 'http://example.com/', retries=False)

Errors will be wrapped in MaxRetryError unless retries are disabled, in which case the causing exception will be raised.

Parameters:
  • total (int) –

    Total number of retries to allow. Takes precedence over other counts.

    Set to None to remove this constraint and fall back on other counts. It’s a good idea to set this to some sensibly-high value to account for unexpected edge cases and avoid infinite retry loops.

    Set to 0 to fail on the first retry.

    Set to False to disable and imply raise_on_redirect=False.

  • connect (int) –

    How many connection-related errors to retry on.

    These are errors raised before the request is sent to the remote server, which we assume has not triggered the server to process the request.

    Set to 0 to fail on the first retry of this type.

  • read (int) –

    How many times to retry on read errors.

    These errors are raised after the request was sent to the server, so the request may have side-effects.

    Set to 0 to fail on the first retry of this type.

  • redirect (int) –

    How many redirects to perform. Limit this to avoid infinite redirect loops.

    A redirect is a HTTP response with a status code 301, 302, 303, 307 or 308.

    Set to 0 to fail on the first retry of this type.

    Set to False to disable and imply raise_on_redirect=False.

  • method_whitelist (iterable) –

    Set of uppercased HTTP method verbs that we should retry on.

    By default, we only retry on methods which are considered to be indempotent (multiple requests with the same parameters end with the same state). See Retry.DEFAULT_METHOD_WHITELIST.

  • status_forcelist (iterable) –

    A set of HTTP status codes that we should force a retry on.

    By default, this is disabled with None.

  • backoff_factor (float) –

    A backoff factor to apply between attempts. urllib3 will sleep for:

    {backoff factor} * (2 ^ ({number of total retries} - 1))
    

    seconds. If the backoff_factor is 0.1, then sleep() will sleep for [0.1s, 0.2s, 0.4s, …] between retries. It will never be longer than Retry.BACKOFF_MAX.

    By default, backoff is disabled (set to 0).

  • raise_on_redirect (bool) – Whether, if the number of redirects is exhausted, to raise a MaxRetryError, or to return a response with a response code in the 3xx range.
__init__(total=10, connect=None, read=None, redirect=None, method_whitelist=DEFAULT_METHOD_WHITELIST, status_forcelist=None, backoff_factor=0, raise_on_redirect=True, _observed_errors=0)
new(**kw)
from_int(retries, redirect=True, default=None)

Backwards-compatibility for the old retries format.

get_backoff_time()

Formula for computing the current backoff

Return type:float
sleep()

Sleep between retry attempts using an exponential backoff.

By default, the backoff factor is 0 and this method will return immediately.

_is_connection_error(err)

Errors when we’re fairly sure that the server did not receive the request, so it should be safe to retry.

_is_read_error(err)

Errors that occur after the request has been started, so we should assume that the server began processing it.

is_forced_retry(method, status_code)

Is this method/status code retryable? (Based on method/codes whitelists)

is_exhausted()

Are we out of retries?

increment(method=None, url=None, response=None, error=None, _pool=None, _stacktrace=None)

Return a new Retry object with incremented retry counters.

Parameters:
  • response (HTTPResponse) – A response object, or None, if the server did not return a response.
  • error (Exception) – An error encountered during the request, or None if the response was received successfully.
Returns:

A new Retry object.

__repr__()