530 lines
18 KiB
Python
530 lines
18 KiB
Python
|
from __future__ import annotations
|
||
|
|
|
||
|
|
import email
|
||
|
|
import logging
|
||
|
|
import random
|
||
|
|
import re
|
||
|
|
import time
|
||
|
|
import typing
|
||
|
|
from itertools import takewhile
|
||
|
|
from types import TracebackType
|
||
|
|
|
||
|
|
from ..exceptions import (
|
||
|
|
ConnectTimeoutError,
|
||
|
|
InvalidHeader,
|
||
|
|
MaxRetryError,
|
||
|
|
ProtocolError,
|
||
|
|
ProxyError,
|
||
|
|
ReadTimeoutError,
|
||
|
|
ResponseError,
|
||
|
|
)
|
||
|
|
from .util import reraise
|
||
|
|
|
||
|
|
if typing.TYPE_CHECKING:
|
||
|
|
from ..connectionpool import ConnectionPool
|
||
|
|
from ..response import BaseHTTPResponse
|
||
|
|
|
||
|
|
log = logging.getLogger(__name__)
|
||
|
|
|
||
|
|
|
||
|
|
# Data structure for representing the metadata of requests that result in a retry.
|
||
|
|
class RequestHistory(typing.NamedTuple):
|
||
|
|
method: str | None
|
||
|
|
url: str | None
|
||
|
|
error: Exception | None
|
||
|
|
status: int | None
|
||
|
|
redirect_location: str | None
|
||
|
|
|
||
|
|
|
||
|
|
class Retry:
|
||
|
|
"""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:
|
||
|
|
|
||
|
|
.. code-block:: python
|
||
|
|
|
||
|
|
retries = Retry(connect=5, read=2, redirect=5)
|
||
|
|
http = PoolManager(retries=retries)
|
||
|
|
response = http.request("GET", "https://example.com/")
|
||
|
|
|
||
|
|
Or per-request (which overrides the default for the pool):
|
||
|
|
|
||
|
|
.. code-block:: python
|
||
|
|
|
||
|
|
response = http.request("GET", "https://example.com/", retries=Retry(10))
|
||
|
|
|
||
|
|
Retries can be disabled by passing ``False``:
|
||
|
|
|
||
|
|
.. code-block:: python
|
||
|
|
|
||
|
|
response = http.request("GET", "https://example.com/", retries=False)
|
||
|
|
|
||
|
|
Errors will be wrapped in :class:`~urllib3.exceptions.MaxRetryError` unless
|
||
|
|
retries are disabled, in which case the causing exception will be raised.
|
||
|
|
|
||
|
|
:param int total:
|
||
|
|
Total number of retries to allow. Takes precedence over other counts.
|
||
|
|
|
||
|
|
Set to ``None`` to remove this constraint and fall back on other
|
||
|
|
counts.
|
||
|
|
|
||
|
|
Set to ``0`` to fail on the first retry.
|
||
|
|
|
||
|
|
Set to ``False`` to disable and imply ``raise_on_redirect=False``.
|
||
|
|
|
||
|
|
:param int connect:
|
||
|
|
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.
|
||
|
|
|
||
|
|
:param int read:
|
||
|
|
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.
|
||
|
|
|
||
|
|
:param int redirect:
|
||
|
|
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``.
|
||
|
|
|
||
|
|
:param int status:
|
||
|
|
How many times to retry on bad status codes.
|
||
|
|
|
||
|
|
These are retries made on responses, where status code matches
|
||
|
|
``status_forcelist``.
|
||
|
|
|
||
|
|
Set to ``0`` to fail on the first retry of this type.
|
||
|
|
|
||
|
|
:param int other:
|
||
|
|
How many times to retry on other errors.
|
||
|
|
|
||
|
|
Other errors are errors that are not connect, read, redirect or status errors.
|
||
|
|
These errors might be raised after the request was sent to the server, so the
|
||
|
|
request might have side-effects.
|
||
|
|
|
||
|
|
Set to ``0`` to fail on the first retry of this type.
|
||
|
|
|
||
|
|
If ``total`` is not set, it's a good idea to set this to 0 to account
|
||
|
|
for unexpected edge cases and avoid infinite retry loops.
|
||
|
|
|
||
|
|
:param Collection allowed_methods:
|
||
|
|
Set of uppercased HTTP method verbs that we should retry on.
|
||
|
|
|
||
|
|
By default, we only retry on methods which are considered to be
|
||
|
|
idempotent (multiple requests with the same parameters end with the
|
||
|
|
same state). See :attr:`Retry.DEFAULT_ALLOWED_METHODS`.
|
||
|
|
|
||
|
|
Set to a ``None`` value to retry on any verb.
|
||
|
|
|
||
|
|
:param Collection status_forcelist:
|
||
|
|
A set of integer HTTP status codes that we should force a retry on.
|
||
|
|
A retry is initiated if the request method is in ``allowed_methods``
|
||
|
|
and the response status code is in ``status_forcelist``.
|
||
|
|
|
||
|
|
By default, this is disabled with ``None``.
|
||
|
|
|
||
|
|
:param float backoff_factor:
|
||
|
|
A backoff factor to apply between attempts after the second try
|
||
|
|
(most errors are resolved immediately by a second try without a
|
||
|
|
delay). urllib3 will sleep for::
|
||
|
|
|
||
|
|
{backoff factor} * (2 ** ({number of previous retries}))
|
||
|
|
|
||
|
|
seconds. If `backoff_jitter` is non-zero, this sleep is extended by::
|
||
|
|
|
||
|
|
random.uniform(0, {backoff jitter})
|
||
|
|
|
||
|
|
seconds. For example, if the backoff_factor is 0.1, then :func:`Retry.sleep` will
|
||
|
|
sleep for [0.0s, 0.2s, 0.4s, 0.8s, ...] between retries. No backoff will ever
|
||
|
|
be longer than `backoff_max`.
|
||
|
|
|
||
|
|
By default, backoff is disabled (factor set to 0).
|
||
|
|
|
||
|
|
:param bool raise_on_redirect: 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.
|
||
|
|
|
||
|
|
:param bool raise_on_status: Similar meaning to ``raise_on_redirect``:
|
||
|
|
whether we should raise an exception, or return a response,
|
||
|
|
if status falls in ``status_forcelist`` range and retries have
|
||
|
|
been exhausted.
|
||
|
|
|
||
|
|
:param tuple history: The history of the request encountered during
|
||
|
|
each call to :meth:`~Retry.increment`. The list is in the order
|
||
|
|
the requests occurred. Each list item is of class :class:`RequestHistory`.
|
||
|
|
|
||
|
|
:param bool respect_retry_after_header:
|
||
|
|
Whether to respect Retry-After header on status codes defined as
|
||
|
|
:attr:`Retry.RETRY_AFTER_STATUS_CODES` or not.
|
||
|
|
|
||
|
|
:param Collection remove_headers_on_redirect:
|
||
|
|
Sequence of headers to remove from the request when a response
|
||
|
|
indicating a redirect is returned before firing off the redirected
|
||
|
|
request.
|
||
|
|
"""
|
||
|
|
|
||
|
|
#: Default methods to be used for ``allowed_methods``
|
||
|
|
DEFAULT_ALLOWED_METHODS = frozenset(
|
||
|
|
["HEAD", "GET", "PUT", "DELETE", "OPTIONS", "TRACE"]
|
||
|
|
)
|
||
|
|
|
||
|
|
#: Default status codes to be used for ``status_forcelist``
|
||
|
|
RETRY_AFTER_STATUS_CODES = frozenset([413, 429, 503])
|
||
|
|
|
||
|
|
#: Default headers to be used for ``remove_headers_on_redirect``
|
||
|
|
DEFAULT_REMOVE_HEADERS_ON_REDIRECT = frozenset(["Cookie", "Authorization"])
|
||
|
|
|
||
|
|
#: Default maximum backoff time.
|
||
|
|
DEFAULT_BACKOFF_MAX = 120
|
||
|
|
|
||
|
|
# Backward compatibility; assigned outside of the class.
|
||
|
|
DEFAULT: typing.ClassVar[Retry]
|
||
|
|
|
||
|
|
def __init__(
|
||
|
|
self,
|
||
|
|
total: bool | int | None = 10,
|
||
|
|
connect: int | None = None,
|
||
|
|
read: int | None = None,
|
||
|
|
redirect: bool | int | None = None,
|
||
|
|
status: int | None = None,
|
||
|
|
other: int | None = None,
|
||
|
|
allowed_methods: typing.Collection[str] | None = DEFAULT_ALLOWED_METHODS,
|
||
|
|
status_forcelist: typing.Collection[int] | None = None,
|
||
|
|
backoff_factor: float = 0,
|
||
|
|
backoff_max: float = DEFAULT_BACKOFF_MAX,
|
||
|
|
raise_on_redirect: bool = True,
|
||
|
|
raise_on_status: bool = True,
|
||
|
|
history: tuple[RequestHistory, ...] | None = None,
|
||
|
|
respect_retry_after_header: bool = True,
|
||
|
|
remove_headers_on_redirect: typing.Collection[
|
||
|
|
str
|
||
|
|
] = DEFAULT_REMOVE_HEADERS_ON_REDIRECT,
|
||
|
|
backoff_jitter: float = 0.0,
|
||
|
|
) -> None:
|
||
|
|
self.total = total
|
||
|
|
self.connect = connect
|
||
|
|
self.read = read
|
||
|
|
self.status = status
|
||
|
|
self.other = other
|
||
|
|
|
||
|
|
if redirect is False or total is False:
|
||
|
|
redirect = 0
|
||
|
|
raise_on_redirect = False
|
||
|
|
|
||
|
|
self.redirect = redirect
|
||
|
|
self.status_forcelist = status_forcelist or set()
|
||
|
|
self.allowed_methods = allowed_methods
|
||
|
|
self.backoff_factor = backoff_factor
|
||
|
|
self.backoff_max = backoff_max
|
||
|
|
self.raise_on_redirect = raise_on_redirect
|
||
|
|
self.raise_on_status = raise_on_status
|
||
|
|
self.history = history or ()
|
||
|
|
self.respect_retry_after_header = respect_retry_after_header
|
||
|
|
self.remove_headers_on_redirect = frozenset(
|
||
|
|
h.lower() for h in remove_headers_on_redirect
|
||
|
|
)
|
||
|
|
self.backoff_jitter = backoff_jitter
|
||
|
|
|
||
|
|
def new(self, **kw: typing.Any) -> Retry:
|
||
|
|
params = dict(
|
||
|
|
total=self.total,
|
||
|
|
connect=self.connect,
|
||
|
|
read=self.read,
|
||
|
|
redirect=self.redirect,
|
||
|
|
status=self.status,
|
||
|
|
other=self.other,
|
||
|
|
allowed_methods=self.allowed_methods,
|
||
|
|
status_forcelist=self.status_forcelist,
|
||
|
|
backoff_factor=self.backoff_factor,
|
||
|
|
backoff_max=self.backoff_max,
|
||
|
|
raise_on_redirect=self.raise_on_redirect,
|
||
|
|
raise_on_status=self.raise_on_status,
|
||
|
|
history=self.history,
|
||
|
|
remove_headers_on_redirect=self.remove_headers_on_redirect,
|
||
|
|
respect_retry_after_header=self.respect_retry_after_header,
|
||
|
|
backoff_jitter=self.backoff_jitter,
|
||
|
|
)
|
||
|
|
|
||
|
|
params.update(kw)
|
||
|
|
return type(self)(**params) # type: ignore[arg-type]
|
||
|
|
|
||
|
|
@classmethod
|
||
|
|
def from_int(
|
||
|
|
cls,
|
||
|
|
retries: Retry | bool | int | None,
|
||
|
|
redirect: bool | int | None = True,
|
||
|
|
default: Retry | bool | int | None = None,
|
||
|
|
) -> Retry:
|
||
|
|
"""Backwards-compatibility for the old retries format."""
|
||
|
|
if retries is None:
|
||
|
|
retries = default if default is not None else cls.DEFAULT
|
||
|
|
|
||
|
|
if isinstance(retries, Retry):
|
||
|
|
return retries
|
||
|
|
|
||
|
|
redirect = bool(redirect) and None
|
||
|
|
new_retries = cls(retries, redirect=redirect)
|
||
|
|
log.debug("Converted retries value: %r -> %r", retries, new_retries)
|
||
|
|
return new_retries
|
||
|
|
|
||
|
|
def get_backoff_time(self) -> float:
|
||
|
|
"""Formula for computing the current backoff
|
||
|
|
|
||
|
|
:rtype: float
|
||
|
|
"""
|
||
|
|
# We want to consider only the last consecutive errors sequence (Ignore redirects).
|
||
|
|
consecutive_errors_len = len(
|
||
|
|
list(
|
||
|
|
takewhile(lambda x: x.redirect_location is None, reversed(self.history))
|
||
|
|
)
|
||
|
|
)
|
||
|
|
if consecutive_errors_len <= 1:
|
||
|
|
return 0
|
||
|
|
|
||
|
|
backoff_value = self.backoff_factor * (2 ** (consecutive_errors_len - 1))
|
||
|
|
if self.backoff_jitter != 0.0:
|
||
|
|
backoff_value += random.random() * self.backoff_jitter
|
||
|
|
return float(max(0, min(self.backoff_max, backoff_value)))
|
||
|
|
|
||
|
|
def parse_retry_after(self, retry_after: str) -> float:
|
||
|
|
seconds: float
|
||
|
|
# Whitespace: https://tools.ietf.org/html/rfc7230#section-3.2.4
|
||
|
|
if re.match(r"^\s*[0-9]+\s*$", retry_after):
|
||
|
|
seconds = int(retry_after)
|
||
|
|
else:
|
||
|
|
retry_date_tuple = email.utils.parsedate_tz(retry_after)
|
||
|
|
if retry_date_tuple is None:
|
||
|
|
raise InvalidHeader(f"Invalid Retry-After header: {retry_after}")
|
||
|
|
|
||
|
|
retry_date = email.utils.mktime_tz(retry_date_tuple)
|
||
|
|
seconds = retry_date - time.time()
|
||
|
|
|
||
|
|
seconds = max(seconds, 0)
|
||
|
|
|
||
|
|
return seconds
|
||
|
|
|
||
|
|
def get_retry_after(self, response: BaseHTTPResponse) -> float | None:
|
||
|
|
"""Get the value of Retry-After in seconds."""
|
||
|
|
|
||
|
|
retry_after = response.headers.get("Retry-After")
|
||
|
|
|
||
|
|
if retry_after is None:
|
||
|
|
return None
|
||
|
|
|
||
|
|
return self.parse_retry_after(retry_after)
|
||
|
|
|
||
|
|
def sleep_for_retry(self, response: BaseHTTPResponse) -> bool:
|
||
|
|
retry_after = self.get_retry_after(response)
|
||
|
|
if retry_after:
|
||
|
|
time.sleep(retry_after)
|
||
|
|
return True
|
||
|
|
|
||
|
|
return False
|
||
|
|
|
||
|
|
def _sleep_backoff(self) -> None:
|
||
|
|
backoff = self.get_backoff_time()
|
||
|
|
if backoff <= 0:
|
||
|
|
return
|
||
|
|
time.sleep(backoff)
|
||
|
|
|
||
|
|
def sleep(self, response: BaseHTTPResponse | None = None) -> None:
|
||
|
|
"""Sleep between retry attempts.
|
||
|
|
|
||
|
|
This method will respect a server's ``Retry-After`` response header
|
||
|
|
and sleep the duration of the time requested. If that is not present, it
|
||
|
|
will use an exponential backoff. By default, the backoff factor is 0 and
|
||
|
|
this method will return immediately.
|
||
|
|
"""
|
||
|
|
|
||
|
|
if self.respect_retry_after_header and response:
|
||
|
|
slept = self.sleep_for_retry(response)
|
||
|
|
if slept:
|
||
|
|
return
|
||
|
|
|
||
|
|
self._sleep_backoff()
|
||
|
|
|
||
|
|
def _is_connection_error(self, err: Exception) -> bool:
|
||
|
|
"""Errors when we're fairly sure that the server did not receive the
|
||
|
|
request, so it should be safe to retry.
|
||
|
|
"""
|
||
|
|
if isinstance(err, ProxyError):
|
||
|
|
err = err.original_error
|
||
|
|
return isinstance(err, ConnectTimeoutError)
|
||
|
|
|
||
|
|
def _is_read_error(self, err: Exception) -> bool:
|
||
|
|
"""Errors that occur after the request has been started, so we should
|
||
|
|
assume that the server began processing it.
|
||
|
|
"""
|
||
|
|
return isinstance(err, (ReadTimeoutError, ProtocolError))
|
||
|
|
|
||
|
|
def _is_method_retryable(self, method: str) -> bool:
|
||
|
|
"""Checks if a given HTTP method should be retried upon, depending if
|
||
|
|
it is included in the allowed_methods
|
||
|
|
"""
|
||
|
|
if self.allowed_methods and method.upper() not in self.allowed_methods:
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
|
||
|
|
def is_retry(
|
||
|
|
self, method: str, status_code: int, has_retry_after: bool = False
|
||
|
|
) -> bool:
|
||
|
|
"""Is this method/status code retryable? (Based on allowlists and control
|
||
|
|
variables such as the number of total retries to allow, whether to
|
||
|
|
respect the Retry-After header, whether this header is present, and
|
||
|
|
whether the returned status code is on the list of status codes to
|
||
|
|
be retried upon on the presence of the aforementioned header)
|
||
|
|
"""
|
||
|
|
if not self._is_method_retryable(method):
|
||
|
|
return False
|
||
|
|
|
||
|
|
if self.status_forcelist and status_code in self.status_forcelist:
|
||
|
|
return True
|
||
|
|
|
||
|
|
return bool(
|
||
|
|
self.total
|
||
|
|
and self.respect_retry_after_header
|
||
|
|
and has_retry_after
|
||
|
|
and (status_code in self.RETRY_AFTER_STATUS_CODES)
|
||
|
|
)
|
||
|
|
|
||
|
|
def is_exhausted(self) -> bool:
|
||
|
|
"""Are we out of retries?"""
|
||
|
|
retry_counts = [
|
||
|
|
x
|
||
|
|
for x in (
|
||
|
|
self.total,
|
||
|
|
self.connect,
|
||
|
|
self.read,
|
||
|
|
self.redirect,
|
||
|
|
self.status,
|
||
|
|
self.other,
|
||
|
|
)
|
||
|
|
if x
|
||
|
|
]
|
||
|
|
if not retry_counts:
|
||
|
|
return False
|
||
|
|
|
||
|
|
return min(retry_counts) < 0
|
||
|
|
|
||
|
|
def increment(
|
||
|
|
self,
|
||
|
|
method: str | None = None,
|
||
|
|
url: str | None = None,
|
||
|
|
response: BaseHTTPResponse | None = None,
|
||
|
|
error: Exception | None = None,
|
||
|
|
_pool: ConnectionPool | None = None,
|
||
|
|
_stacktrace: TracebackType | None = None,
|
||
|
|
) -> Retry:
|
||
|
|
"""Return a new Retry object with incremented retry counters.
|
||
|
|
|
||
|
|
:param response: A response object, or None, if the server did not
|
||
|
|
return a response.
|
||
|
|
:type response: :class:`~urllib3.response.BaseHTTPResponse`
|
||
|
|
:param Exception error: An error encountered during the request, or
|
||
|
|
None if the response was received successfully.
|
||
|
|
|
||
|
|
:return: A new ``Retry`` object.
|
||
|
|
"""
|
||
|
|
if self.total is False and error:
|
||
|
|
# Disabled, indicate to re-raise the error.
|
||
|
|
raise reraise(type(error), error, _stacktrace)
|
||
|
|
|
||
|
|
total = self.total
|
||
|
|
if total is not None:
|
||
|
|
total -= 1
|
||
|
|
|
||
|
|
connect = self.connect
|
||
|
|
read = self.read
|
||
|
|
redirect = self.redirect
|
||
|
|
status_count = self.status
|
||
|
|
other = self.other
|
||
|
|
cause = "unknown"
|
||
|
|
status = None
|
||
|
|
redirect_location = None
|
||
|
|
|
||
|
|
if error and self._is_connection_error(error):
|
||
|
|
# Connect retry?
|
||
|
|
if connect is False:
|
||
|
|
raise reraise(type(error), error, _stacktrace)
|
||
|
|
elif connect is not None:
|
||
|
|
connect -= 1
|
||
|
|
|
||
|
|
elif error and self._is_read_error(error):
|
||
|
|
# Read retry?
|
||
|
|
if read is False or method is None or not self._is_method_retryable(method):
|
||
|
|
raise reraise(type(error), error, _stacktrace)
|
||
|
|
elif read is not None:
|
||
|
|
read -= 1
|
||
|
|
|
||
|
|
elif error:
|
||
|
|
# Other retry?
|
||
|
|
if other is not None:
|
||
|
|
other -= 1
|
||
|
|
|
||
|
|
elif response and response.get_redirect_location():
|
||
|
|
# Redirect retry?
|
||
|
|
if redirect is not None:
|
||
|
|
redirect -= 1
|
||
|
|
cause = "too many redirects"
|
||
|
|
response_redirect_location = response.get_redirect_location()
|
||
|
|
if response_redirect_location:
|
||
|
|
redirect_location = response_redirect_location
|
||
|
|
status = response.status
|
||
|
|
|
||
|
|
else:
|
||
|
|
# Incrementing because of a server error like a 500 in
|
||
|
|
# status_forcelist and the given method is in the allowed_methods
|
||
|
|
cause = ResponseError.GENERIC_ERROR
|
||
|
|
if response and response.status:
|
||
|
|
if status_count is not None:
|
||
|
|
status_count -= 1
|
||
|
|
cause = ResponseError.SPECIFIC_ERROR.format(status_code=response.status)
|
||
|
|
status = response.status
|
||
|
|
|
||
|
|
history = self.history + (
|
||
|
|
RequestHistory(method, url, error, status, redirect_location),
|
||
|
|
)
|
||
|
|
|
||
|
|
new_retry = self.new(
|
||
|
|
total=total,
|
||
|
|
connect=connect,
|
||
|
|
read=read,
|
||
|
|
redirect=redirect,
|
||
|
|
status=status_count,
|
||
|
|
other=other,
|
||
|
|
history=history,
|
||
|
|
)
|
||
|
|
|
||
|
|
if new_retry.is_exhausted():
|
||
|
|
reason = error or ResponseError(cause)
|
||
|
|
raise MaxRetryError(_pool, url, reason) from reason # type: ignore[arg-type]
|
||
|
|
|
||
|
|
log.debug("Incremented Retry for (url='%s'): %r", url, new_retry)
|
||
|
|
|
||
|
|
return new_retry
|
||
|
|
|
||
|
|
def __repr__(self) -> str:
|
||
|
|
return (
|
||
|
|
f"{type(self).__name__}(total={self.total}, connect={self.connect}, "
|
||
|
|
f"read={self.read}, redirect={self.redirect}, status={self.status})"
|
||
|
|
)
|
||
|
|
|
||
|
|
|
||
|
|
# For backwards compatibility (equivalent to pre-v1.9):
|
||
|
|
Retry.DEFAULT = Retry(3)
|