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"""
This module is the requests implementation of Pipeline ABC
"""
from __future__ import absolute_import # we have a "requests" module that conflicts with "requests" on Py2.7
import logging
import time
from typing import TYPE_CHECKING, List, Callable, Iterator, Any, Union, Dict, Optional # pylint: disable=unused-import
from azure.core.exceptions import (
AzureError,
ClientAuthenticationError,
ServiceRequestError,
)
from ._base import HTTPPolicy
from ._base_async import AsyncHTTPPolicy
from ._retry import RetryPolicy
_LOGGER = logging.getLogger(__name__)
[docs]class AsyncRetryPolicy(RetryPolicy, AsyncHTTPPolicy):
"""Async flavor of the retry policy.
The async retry policy in the pipeline can be configured directly, or tweaked on a per-call basis.
:keyword int retry_total: Total number of retries to allow. Takes precedence over other counts.
Default value is 10.
:keyword int retry_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. Default value is 3.
:keyword int retry_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. Default value is 3.
:keyword int retry_status: How many times to retry on bad status codes. Default value is 3.
:keyword float retry_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).
Retry policy will sleep for: `{backoff factor} * (2 ** ({number of total retries} - 1))`
seconds. If the backoff_factor is 0.1, then the retry will sleep
for [0.0s, 0.2s, 0.4s, ...] between retries. The default value is 0.8.
:keyword int retry_backoff_max: The maximum back off time. Default value is 120 seconds (2 minutes).
.. admonition:: Example:
.. literalinclude:: ../samples/test_example_async.py
:start-after: [START async_retry_policy]
:end-before: [END async_retry_policy]
:language: python
:dedent: 4
:caption: Configuring an async retry policy.
"""
async def _sleep_for_retry(self, response, transport): # pylint:disable=invalid-overridden-method
"""Sleep based on the Retry-After response header value.
:param response: The PipelineResponse object.
:type response: ~azure.core.pipeline.PipelineResponse
:param transport: The HTTP transport type.
"""
retry_after = self.get_retry_after(response)
if retry_after:
await transport.sleep(retry_after)
return True
return False
async def _sleep_backoff(self, settings, transport): # pylint:disable=invalid-overridden-method
"""Sleep using exponential backoff. Immediately returns if backoff is 0.
:param dict settings: The retry settings.
:param transport: The HTTP transport type.
"""
backoff = self.get_backoff_time(settings)
if backoff <= 0:
return
await transport.sleep(backoff)
[docs] async def sleep(self, settings, transport, response=None): # pylint:disable=invalid-overridden-method
"""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.
:param dict settings: The retry settings.
:param transport: The HTTP transport type.
:param response: The PipelineResponse object.
:type response: ~azure.core.pipeline.PipelineResponse
"""
if response:
slept = await self._sleep_for_retry(response, transport)
if slept:
return
await self._sleep_backoff(settings, transport)
[docs] async def send(self, request): # pylint:disable=invalid-overridden-method
"""Uses the configured retry policy to send the request to the next policy in the pipeline.
:param request: The PipelineRequest object
:type request: ~azure.core.pipeline.PipelineRequest
:return: Returns the PipelineResponse or raises error if maximum retries exceeded.
:rtype: ~azure.core.pipeline.PipelineResponse
:raise: ~azure.core.exceptions.AzureError if maximum retries exceeded.
:raise: ~azure.core.exceptions.ClientAuthenticationError if authentication fails
"""
retry_active = True
response = None
retry_settings = self.configure_retries(request.context.options)
self._configure_positions(request, retry_settings)
absolute_timeout = retry_settings['timeout']
is_response_error = True
while retry_active:
try:
start_time = time.time()
self._configure_timeout(request, absolute_timeout, is_response_error)
response = await self.next.send(request)
if self.is_retry(retry_settings, response):
retry_active = self.increment(retry_settings, response=response)
if retry_active:
await self.sleep(retry_settings, request.context.transport, response=response)
is_response_error = True
continue
break
except ClientAuthenticationError: # pylint:disable=try-except-raise
# the authentication policy failed such that the client's request can't
# succeed--we'll never have a response to it, so propagate the exception
raise
except AzureError as err:
if self._is_method_retryable(retry_settings, request.http_request):
retry_active = self.increment(retry_settings, response=request, error=err)
if retry_active:
await self.sleep(retry_settings, request.context.transport)
if isinstance(err, ServiceRequestError):
is_response_error = False
else:
is_response_error = True
continue
raise err
finally:
end_time = time.time()
if absolute_timeout:
absolute_timeout -= (end_time - start_time)
self.update_context(response.context, retry_settings)
return response