Inital Commit
This commit is contained in:
Brett Woodruff
6
Function Source Files/botocore/retries/__init__.py
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6
Function Source Files/botocore/retries/__init__.py
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"""New retry v2 handlers.
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This package obsoletes the botocore/retryhandler.py module and contains
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new retry logic.
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"""
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132
Function Source Files/botocore/retries/adaptive.py
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132
Function Source Files/botocore/retries/adaptive.py
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import logging
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import math
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import threading
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from botocore.retries import bucket, standard, throttling
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logger = logging.getLogger(__name__)
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def register_retry_handler(client):
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clock = bucket.Clock()
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rate_adjustor = throttling.CubicCalculator(
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starting_max_rate=0, start_time=clock.current_time()
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)
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token_bucket = bucket.TokenBucket(max_rate=1, clock=clock)
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rate_clocker = RateClocker(clock)
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throttling_detector = standard.ThrottlingErrorDetector(
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retry_event_adapter=standard.RetryEventAdapter(),
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)
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limiter = ClientRateLimiter(
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rate_adjustor=rate_adjustor,
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rate_clocker=rate_clocker,
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token_bucket=token_bucket,
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throttling_detector=throttling_detector,
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clock=clock,
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)
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client.meta.events.register(
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'before-send',
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limiter.on_sending_request,
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)
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client.meta.events.register(
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'needs-retry',
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limiter.on_receiving_response,
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)
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return limiter
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class ClientRateLimiter:
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_MAX_RATE_ADJUST_SCALE = 2.0
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def __init__(
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self,
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rate_adjustor,
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rate_clocker,
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token_bucket,
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throttling_detector,
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clock,
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):
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self._rate_adjustor = rate_adjustor
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self._rate_clocker = rate_clocker
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self._token_bucket = token_bucket
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self._throttling_detector = throttling_detector
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self._clock = clock
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self._enabled = False
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self._lock = threading.Lock()
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def on_sending_request(self, request, **kwargs):
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if self._enabled:
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self._token_bucket.acquire()
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# Hooked up to needs-retry.
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def on_receiving_response(self, **kwargs):
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measured_rate = self._rate_clocker.record()
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timestamp = self._clock.current_time()
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with self._lock:
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if not self._throttling_detector.is_throttling_error(**kwargs):
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new_rate = self._rate_adjustor.success_received(timestamp)
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else:
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if not self._enabled:
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rate_to_use = measured_rate
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else:
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rate_to_use = min(
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measured_rate, self._token_bucket.max_rate
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)
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new_rate = self._rate_adjustor.error_received(
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rate_to_use, timestamp
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)
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logger.debug(
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"Throttling response received, new send rate: %s "
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"measured rate: %s, token bucket capacity "
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"available: %s",
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new_rate,
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measured_rate,
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self._token_bucket.available_capacity,
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)
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self._enabled = True
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self._token_bucket.max_rate = min(
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new_rate, self._MAX_RATE_ADJUST_SCALE * measured_rate
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)
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class RateClocker:
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"""Tracks the rate at which a client is sending a request."""
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_DEFAULT_SMOOTHING = 0.8
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# Update the rate every _TIME_BUCKET_RANGE seconds.
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_TIME_BUCKET_RANGE = 0.5
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def __init__(
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self,
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clock,
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smoothing=_DEFAULT_SMOOTHING,
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time_bucket_range=_TIME_BUCKET_RANGE,
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):
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self._clock = clock
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self._measured_rate = 0
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self._smoothing = smoothing
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self._last_bucket = math.floor(self._clock.current_time())
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self._time_bucket_scale = 1 / self._TIME_BUCKET_RANGE
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self._count = 0
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self._lock = threading.Lock()
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def record(self, amount=1):
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with self._lock:
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t = self._clock.current_time()
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bucket = (
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math.floor(t * self._time_bucket_scale)
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/ self._time_bucket_scale
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)
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self._count += amount
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if bucket > self._last_bucket:
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current_rate = self._count / float(bucket - self._last_bucket)
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self._measured_rate = (current_rate * self._smoothing) + (
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self._measured_rate * (1 - self._smoothing)
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)
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self._count = 0
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self._last_bucket = bucket
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return self._measured_rate
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@property
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def measured_rate(self):
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return self._measured_rate
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26
Function Source Files/botocore/retries/base.py
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26
Function Source Files/botocore/retries/base.py
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@@ -0,0 +1,26 @@
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class BaseRetryBackoff:
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def delay_amount(self, context):
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"""Calculate how long we should delay before retrying.
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:type context: RetryContext
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"""
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raise NotImplementedError("delay_amount")
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class BaseRetryableChecker:
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"""Base class for determining if a retry should happen.
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This base class checks for specific retryable conditions.
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A single retryable checker doesn't necessarily indicate a retry
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will happen. It's up to the ``RetryPolicy`` to use its
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``BaseRetryableCheckers`` to make the final decision on whether a retry
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should happen.
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"""
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def is_retryable(self, context):
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"""Returns True if retryable, False if not.
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:type context: RetryContext
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"""
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raise NotImplementedError("is_retryable")
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114
Function Source Files/botocore/retries/bucket.py
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114
Function Source Files/botocore/retries/bucket.py
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@@ -0,0 +1,114 @@
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"""This module implements token buckets used for client side throttling."""
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import threading
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import time
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from botocore.exceptions import CapacityNotAvailableError
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class Clock:
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def __init__(self):
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pass
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def sleep(self, amount):
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time.sleep(amount)
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def current_time(self):
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return time.time()
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class TokenBucket:
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_MIN_RATE = 0.5
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def __init__(self, max_rate, clock, min_rate=_MIN_RATE):
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self._fill_rate = None
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self._max_capacity = None
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self._current_capacity = 0
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self._clock = clock
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self._last_timestamp = None
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self._min_rate = min_rate
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self._lock = threading.Lock()
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self._new_fill_rate_condition = threading.Condition(self._lock)
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self.max_rate = max_rate
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@property
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def max_rate(self):
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return self._fill_rate
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@max_rate.setter
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def max_rate(self, value):
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with self._new_fill_rate_condition:
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# Before we can change the rate we need to fill any pending
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# tokens we might have based on the current rate. If we don't
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# do this it means everything since the last recorded timestamp
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# will accumulate at the rate we're about to set which isn't
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# correct.
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self._refill()
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self._fill_rate = max(value, self._min_rate)
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if value >= 1:
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self._max_capacity = value
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else:
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self._max_capacity = 1
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# If we're scaling down, we also can't have a capacity that's
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# more than our max_capacity.
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self._current_capacity = min(
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self._current_capacity, self._max_capacity
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)
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self._new_fill_rate_condition.notify()
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@property
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def max_capacity(self):
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return self._max_capacity
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@property
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def available_capacity(self):
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return self._current_capacity
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def acquire(self, amount=1, block=True):
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"""Acquire token or return amount of time until next token available.
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If block is True, then this method will block until there's sufficient
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capacity to acquire the desired amount.
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If block is False, then this method will return True is capacity
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was successfully acquired, False otherwise.
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"""
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with self._new_fill_rate_condition:
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return self._acquire(amount=amount, block=block)
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def _acquire(self, amount, block):
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self._refill()
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if amount <= self._current_capacity:
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self._current_capacity -= amount
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return True
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else:
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if not block:
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raise CapacityNotAvailableError()
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# Not enough capacity.
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sleep_amount = self._sleep_amount(amount)
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while sleep_amount > 0:
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# Until python3.2, wait() always returned None so we can't
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# tell if a timeout occurred waiting on the cond var.
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# Because of this we'll unconditionally call _refill().
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# The downside to this is that we were waken up via
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# a notify(), we're calling unnecessarily calling _refill() an
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# extra time.
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self._new_fill_rate_condition.wait(sleep_amount)
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self._refill()
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sleep_amount = self._sleep_amount(amount)
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self._current_capacity -= amount
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return True
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def _sleep_amount(self, amount):
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return (amount - self._current_capacity) / self._fill_rate
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def _refill(self):
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timestamp = self._clock.current_time()
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if self._last_timestamp is None:
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self._last_timestamp = timestamp
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return
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current_capacity = self._current_capacity
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fill_amount = (timestamp - self._last_timestamp) * self._fill_rate
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new_capacity = min(self._max_capacity, current_capacity + fill_amount)
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self._current_capacity = new_capacity
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self._last_timestamp = timestamp
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56
Function Source Files/botocore/retries/quota.py
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56
Function Source Files/botocore/retries/quota.py
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@@ -0,0 +1,56 @@
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"""Retry quota implementation.
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"""
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import threading
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class RetryQuota:
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INITIAL_CAPACITY = 500
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def __init__(self, initial_capacity=INITIAL_CAPACITY, lock=None):
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self._max_capacity = initial_capacity
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self._available_capacity = initial_capacity
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if lock is None:
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lock = threading.Lock()
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self._lock = lock
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def acquire(self, capacity_amount):
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"""Attempt to aquire a certain amount of capacity.
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If there's not sufficient amount of capacity available, ``False``
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is returned. Otherwise, ``True`` is returned, which indicates that
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capacity was successfully allocated.
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"""
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# The acquire() is only called when we encounter a retryable
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# response so we aren't worried about locking the entire method.
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with self._lock:
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if capacity_amount > self._available_capacity:
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return False
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self._available_capacity -= capacity_amount
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return True
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def release(self, capacity_amount):
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"""Release capacity back to the retry quota.
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The capacity being released will be truncated if necessary
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to ensure the max capacity is never exceeded.
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"""
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# Implementation note: The release() method is called as part
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# of the "after-call" event, which means it gets invoked for
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# every API call. In the common case where the request is
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# successful and we're at full capacity, we can avoid locking.
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# We can't exceed max capacity so there's no work we have to do.
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if self._max_capacity == self._available_capacity:
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return
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with self._lock:
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amount = min(
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self._max_capacity - self._available_capacity, capacity_amount
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)
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self._available_capacity += amount
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@property
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def available_capacity(self):
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return self._available_capacity
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50
Function Source Files/botocore/retries/special.py
Normal file
50
Function Source Files/botocore/retries/special.py
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@@ -0,0 +1,50 @@
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"""Special cased retries.
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These are additional retry cases we still have to handle from the legacy
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retry handler. They don't make sense as part of the standard mode retry
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module. Ideally we should be able to remove this module.
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"""
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import logging
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from binascii import crc32
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from botocore.retries.base import BaseRetryableChecker
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logger = logging.getLogger(__name__)
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# TODO: This is an ideal candidate for the retryable trait once that's
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# available.
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class RetryIDPCommunicationError(BaseRetryableChecker):
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_SERVICE_NAME = 'sts'
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def is_retryable(self, context):
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service_name = context.operation_model.service_model.service_name
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if service_name != self._SERVICE_NAME:
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return False
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error_code = context.get_error_code()
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return error_code == 'IDPCommunicationError'
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class RetryDDBChecksumError(BaseRetryableChecker):
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_CHECKSUM_HEADER = 'x-amz-crc32'
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_SERVICE_NAME = 'dynamodb'
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def is_retryable(self, context):
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service_name = context.operation_model.service_model.service_name
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if service_name != self._SERVICE_NAME:
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return False
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if context.http_response is None:
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return False
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checksum = context.http_response.headers.get(self._CHECKSUM_HEADER)
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if checksum is None:
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return False
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actual_crc32 = crc32(context.http_response.content) & 0xFFFFFFFF
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if actual_crc32 != int(checksum):
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logger.debug(
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"DynamoDB crc32 checksum does not match, "
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"expected: %s, actual: %s",
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checksum,
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actual_crc32,
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)
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return True
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531
Function Source Files/botocore/retries/standard.py
Normal file
531
Function Source Files/botocore/retries/standard.py
Normal file
@@ -0,0 +1,531 @@
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"""Standard retry behavior.
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This contains the default standard retry behavior.
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It provides consistent behavior with other AWS SDKs.
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The key base classes uses for retries:
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* ``BaseRetryableChecker`` - Use to check a specific condition that
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indicates a retry should happen. This can include things like
|
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max attempts, HTTP status code checks, error code checks etc.
|
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* ``RetryBackoff`` - Use to determine how long we should backoff until
|
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we retry a request. This is the class that will implement delay such
|
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as exponential backoff.
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* ``RetryPolicy`` - Main class that determines if a retry should
|
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happen. It can combine data from a various BaseRetryableCheckers
|
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to make a final call as to whether or not a retry should happen.
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It then uses a ``BaseRetryBackoff`` to determine how long to delay.
|
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* ``RetryHandler`` - The bridge between botocore's event system
|
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used by endpoint.py to manage retries and the interfaces defined
|
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in this module.
|
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|
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This allows us to define an API that has minimal coupling to the event
|
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based API used by botocore.
|
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|
||||
"""
|
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import logging
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import random
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|
||||
from botocore.exceptions import (
|
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ConnectionError,
|
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ConnectTimeoutError,
|
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HTTPClientError,
|
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ReadTimeoutError,
|
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)
|
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from botocore.retries import quota, special
|
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from botocore.retries.base import BaseRetryableChecker, BaseRetryBackoff
|
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|
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DEFAULT_MAX_ATTEMPTS = 3
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logger = logging.getLogger(__name__)
|
||||
|
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|
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def register_retry_handler(client, max_attempts=DEFAULT_MAX_ATTEMPTS):
|
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retry_quota = RetryQuotaChecker(quota.RetryQuota())
|
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|
||||
service_id = client.meta.service_model.service_id
|
||||
service_event_name = service_id.hyphenize()
|
||||
client.meta.events.register(
|
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f'after-call.{service_event_name}', retry_quota.release_retry_quota
|
||||
)
|
||||
|
||||
handler = RetryHandler(
|
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retry_policy=RetryPolicy(
|
||||
retry_checker=StandardRetryConditions(max_attempts=max_attempts),
|
||||
retry_backoff=ExponentialBackoff(),
|
||||
),
|
||||
retry_event_adapter=RetryEventAdapter(),
|
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retry_quota=retry_quota,
|
||||
)
|
||||
|
||||
unique_id = 'retry-config-%s' % service_event_name
|
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client.meta.events.register(
|
||||
'needs-retry.%s' % service_event_name,
|
||||
handler.needs_retry,
|
||||
unique_id=unique_id,
|
||||
)
|
||||
return handler
|
||||
|
||||
|
||||
class RetryHandler:
|
||||
"""Bridge between botocore's event system and this module.
|
||||
|
||||
This class is intended to be hooked to botocore's event system
|
||||
as an event handler.
|
||||
"""
|
||||
|
||||
def __init__(self, retry_policy, retry_event_adapter, retry_quota):
|
||||
self._retry_policy = retry_policy
|
||||
self._retry_event_adapter = retry_event_adapter
|
||||
self._retry_quota = retry_quota
|
||||
|
||||
def needs_retry(self, **kwargs):
|
||||
"""Connect as a handler to the needs-retry event."""
|
||||
retry_delay = None
|
||||
context = self._retry_event_adapter.create_retry_context(**kwargs)
|
||||
if self._retry_policy.should_retry(context):
|
||||
# Before we can retry we need to ensure we have sufficient
|
||||
# capacity in our retry quota.
|
||||
if self._retry_quota.acquire_retry_quota(context):
|
||||
retry_delay = self._retry_policy.compute_retry_delay(context)
|
||||
logger.debug(
|
||||
"Retry needed, retrying request after delay of: %s",
|
||||
retry_delay,
|
||||
)
|
||||
else:
|
||||
logger.debug(
|
||||
"Retry needed but retry quota reached, "
|
||||
"not retrying request."
|
||||
)
|
||||
else:
|
||||
logger.debug("Not retrying request.")
|
||||
self._retry_event_adapter.adapt_retry_response_from_context(context)
|
||||
return retry_delay
|
||||
|
||||
|
||||
class RetryEventAdapter:
|
||||
"""Adapter to existing retry interface used in the endpoints layer.
|
||||
|
||||
This existing interface for determining if a retry needs to happen
|
||||
is event based and used in ``botocore.endpoint``. The interface has
|
||||
grown organically over the years and could use some cleanup. This
|
||||
adapter converts that interface into the interface used by the
|
||||
new retry strategies.
|
||||
|
||||
"""
|
||||
|
||||
def create_retry_context(self, **kwargs):
|
||||
"""Create context based on needs-retry kwargs."""
|
||||
response = kwargs['response']
|
||||
if response is None:
|
||||
# If response is None it means that an exception was raised
|
||||
# because we never received a response from the service. This
|
||||
# could be something like a ConnectionError we get from our
|
||||
# http layer.
|
||||
http_response = None
|
||||
parsed_response = None
|
||||
else:
|
||||
http_response, parsed_response = response
|
||||
# This provides isolation between the kwargs emitted in the
|
||||
# needs-retry event, and what this module uses to check for
|
||||
# retries.
|
||||
context = RetryContext(
|
||||
attempt_number=kwargs['attempts'],
|
||||
operation_model=kwargs['operation'],
|
||||
http_response=http_response,
|
||||
parsed_response=parsed_response,
|
||||
caught_exception=kwargs['caught_exception'],
|
||||
request_context=kwargs['request_dict']['context'],
|
||||
)
|
||||
return context
|
||||
|
||||
def adapt_retry_response_from_context(self, context):
|
||||
"""Modify response back to user back from context."""
|
||||
# This will mutate attributes that are returned back to the end
|
||||
# user. We do it this way so that all the various retry classes
|
||||
# don't mutate any input parameters from the needs-retry event.
|
||||
metadata = context.get_retry_metadata()
|
||||
if context.parsed_response is not None:
|
||||
context.parsed_response.setdefault('ResponseMetadata', {}).update(
|
||||
metadata
|
||||
)
|
||||
|
||||
|
||||
# Implementation note: this is meant to encapsulate all the misc stuff
|
||||
# that gets sent in the needs-retry event. This is mapped so that params
|
||||
# are more clear and explicit.
|
||||
class RetryContext:
|
||||
"""Normalize a response that we use to check if a retry should occur.
|
||||
|
||||
This class smoothes over the different types of responses we may get
|
||||
from a service including:
|
||||
|
||||
* A modeled error response from the service that contains a service
|
||||
code and error message.
|
||||
* A raw HTTP response that doesn't contain service protocol specific
|
||||
error keys.
|
||||
* An exception received while attempting to retrieve a response.
|
||||
This could be a ConnectionError we receive from our HTTP layer which
|
||||
could represent that we weren't able to receive a response from
|
||||
the service.
|
||||
|
||||
This class guarantees that at least one of the above attributes will be
|
||||
non None.
|
||||
|
||||
This class is meant to provide a read-only view into the properties
|
||||
associated with a possible retryable response. None of the properties
|
||||
are meant to be modified directly.
|
||||
|
||||
"""
|
||||
|
||||
def __init__(
|
||||
self,
|
||||
attempt_number,
|
||||
operation_model=None,
|
||||
parsed_response=None,
|
||||
http_response=None,
|
||||
caught_exception=None,
|
||||
request_context=None,
|
||||
):
|
||||
# 1-based attempt number.
|
||||
self.attempt_number = attempt_number
|
||||
self.operation_model = operation_model
|
||||
# This is the parsed response dictionary we get from parsing
|
||||
# the HTTP response from the service.
|
||||
self.parsed_response = parsed_response
|
||||
# This is an instance of botocore.awsrequest.AWSResponse.
|
||||
self.http_response = http_response
|
||||
# This is a subclass of Exception that will be non None if
|
||||
# an exception was raised when retrying to retrieve a response.
|
||||
self.caught_exception = caught_exception
|
||||
# This is the request context dictionary that's added to the
|
||||
# request dict. This is used to story any additional state
|
||||
# about the request. We use this for storing retry quota
|
||||
# capacity.
|
||||
if request_context is None:
|
||||
request_context = {}
|
||||
self.request_context = request_context
|
||||
self._retry_metadata = {}
|
||||
|
||||
# These are misc helper methods to avoid duplication in the various
|
||||
# checkers.
|
||||
def get_error_code(self):
|
||||
"""Check if there was a parsed response with an error code.
|
||||
|
||||
If we could not find any error codes, ``None`` is returned.
|
||||
|
||||
"""
|
||||
if self.parsed_response is None:
|
||||
return
|
||||
error = self.parsed_response.get('Error', {})
|
||||
if not isinstance(error, dict):
|
||||
return
|
||||
return error.get('Code')
|
||||
|
||||
def add_retry_metadata(self, **kwargs):
|
||||
"""Add key/value pairs to the retry metadata.
|
||||
|
||||
This allows any objects during the retry process to add
|
||||
metadata about any checks/validations that happened.
|
||||
|
||||
This gets added to the response metadata in the retry handler.
|
||||
|
||||
"""
|
||||
self._retry_metadata.update(**kwargs)
|
||||
|
||||
def get_retry_metadata(self):
|
||||
return self._retry_metadata.copy()
|
||||
|
||||
|
||||
class RetryPolicy:
|
||||
def __init__(self, retry_checker, retry_backoff):
|
||||
self._retry_checker = retry_checker
|
||||
self._retry_backoff = retry_backoff
|
||||
|
||||
def should_retry(self, context):
|
||||
return self._retry_checker.is_retryable(context)
|
||||
|
||||
def compute_retry_delay(self, context):
|
||||
return self._retry_backoff.delay_amount(context)
|
||||
|
||||
|
||||
class ExponentialBackoff(BaseRetryBackoff):
|
||||
_BASE = 2
|
||||
_MAX_BACKOFF = 20
|
||||
|
||||
def __init__(self, max_backoff=20, random=random.random):
|
||||
self._base = self._BASE
|
||||
self._max_backoff = max_backoff
|
||||
self._random = random
|
||||
|
||||
def delay_amount(self, context):
|
||||
"""Calculates delay based on exponential backoff.
|
||||
|
||||
This class implements truncated binary exponential backoff
|
||||
with jitter::
|
||||
|
||||
t_i = min(rand(0, 1) * 2 ** attempt, MAX_BACKOFF)
|
||||
|
||||
where ``i`` is the request attempt (0 based).
|
||||
|
||||
"""
|
||||
# The context.attempt_number is a 1-based value, but we have
|
||||
# to calculate the delay based on i based a 0-based value. We
|
||||
# want the first delay to just be ``rand(0, 1)``.
|
||||
return min(
|
||||
self._random() * (self._base ** (context.attempt_number - 1)),
|
||||
self._max_backoff,
|
||||
)
|
||||
|
||||
|
||||
class MaxAttemptsChecker(BaseRetryableChecker):
|
||||
def __init__(self, max_attempts):
|
||||
self._max_attempts = max_attempts
|
||||
|
||||
def is_retryable(self, context):
|
||||
under_max_attempts = context.attempt_number < self._max_attempts
|
||||
retries_context = context.request_context.get('retries')
|
||||
if retries_context:
|
||||
retries_context['max'] = max(
|
||||
retries_context.get('max', 0), self._max_attempts
|
||||
)
|
||||
if not under_max_attempts:
|
||||
logger.debug("Max attempts of %s reached.", self._max_attempts)
|
||||
context.add_retry_metadata(MaxAttemptsReached=True)
|
||||
return under_max_attempts
|
||||
|
||||
|
||||
class TransientRetryableChecker(BaseRetryableChecker):
|
||||
_TRANSIENT_ERROR_CODES = [
|
||||
'RequestTimeout',
|
||||
'RequestTimeoutException',
|
||||
'PriorRequestNotComplete',
|
||||
]
|
||||
_TRANSIENT_STATUS_CODES = [500, 502, 503, 504]
|
||||
_TRANSIENT_EXCEPTION_CLS = (
|
||||
ConnectionError,
|
||||
HTTPClientError,
|
||||
)
|
||||
|
||||
def __init__(
|
||||
self,
|
||||
transient_error_codes=None,
|
||||
transient_status_codes=None,
|
||||
transient_exception_cls=None,
|
||||
):
|
||||
if transient_error_codes is None:
|
||||
transient_error_codes = self._TRANSIENT_ERROR_CODES[:]
|
||||
if transient_status_codes is None:
|
||||
transient_status_codes = self._TRANSIENT_STATUS_CODES[:]
|
||||
if transient_exception_cls is None:
|
||||
transient_exception_cls = self._TRANSIENT_EXCEPTION_CLS
|
||||
self._transient_error_codes = transient_error_codes
|
||||
self._transient_status_codes = transient_status_codes
|
||||
self._transient_exception_cls = transient_exception_cls
|
||||
|
||||
def is_retryable(self, context):
|
||||
if context.get_error_code() in self._transient_error_codes:
|
||||
return True
|
||||
if context.http_response is not None:
|
||||
if (
|
||||
context.http_response.status_code
|
||||
in self._transient_status_codes
|
||||
):
|
||||
return True
|
||||
if context.caught_exception is not None:
|
||||
return isinstance(
|
||||
context.caught_exception, self._transient_exception_cls
|
||||
)
|
||||
return False
|
||||
|
||||
|
||||
class ThrottledRetryableChecker(BaseRetryableChecker):
|
||||
# This is the union of all error codes we've seen that represent
|
||||
# a throttled error.
|
||||
_THROTTLED_ERROR_CODES = [
|
||||
'Throttling',
|
||||
'ThrottlingException',
|
||||
'ThrottledException',
|
||||
'RequestThrottledException',
|
||||
'TooManyRequestsException',
|
||||
'ProvisionedThroughputExceededException',
|
||||
'TransactionInProgressException',
|
||||
'RequestLimitExceeded',
|
||||
'BandwidthLimitExceeded',
|
||||
'LimitExceededException',
|
||||
'RequestThrottled',
|
||||
'SlowDown',
|
||||
'PriorRequestNotComplete',
|
||||
'EC2ThrottledException',
|
||||
]
|
||||
|
||||
def __init__(self, throttled_error_codes=None):
|
||||
if throttled_error_codes is None:
|
||||
throttled_error_codes = self._THROTTLED_ERROR_CODES[:]
|
||||
self._throttled_error_codes = throttled_error_codes
|
||||
|
||||
def is_retryable(self, context):
|
||||
# Only the error code from a parsed service response is used
|
||||
# to determine if the response is a throttled response.
|
||||
return context.get_error_code() in self._throttled_error_codes
|
||||
|
||||
|
||||
class ModeledRetryableChecker(BaseRetryableChecker):
|
||||
"""Check if an error has been modeled as retryable."""
|
||||
|
||||
def __init__(self):
|
||||
self._error_detector = ModeledRetryErrorDetector()
|
||||
|
||||
def is_retryable(self, context):
|
||||
error_code = context.get_error_code()
|
||||
if error_code is None:
|
||||
return False
|
||||
return self._error_detector.detect_error_type(context) is not None
|
||||
|
||||
|
||||
class ModeledRetryErrorDetector:
|
||||
"""Checks whether or not an error is a modeled retryable error."""
|
||||
|
||||
# There are return values from the detect_error_type() method.
|
||||
TRANSIENT_ERROR = 'TRANSIENT_ERROR'
|
||||
THROTTLING_ERROR = 'THROTTLING_ERROR'
|
||||
# This class is lower level than ModeledRetryableChecker, which
|
||||
# implements BaseRetryableChecker. This object allows you to distinguish
|
||||
# between the various types of retryable errors.
|
||||
|
||||
def detect_error_type(self, context):
|
||||
"""Detect the error type associated with an error code and model.
|
||||
|
||||
This will either return:
|
||||
|
||||
* ``self.TRANSIENT_ERROR`` - If the error is a transient error
|
||||
* ``self.THROTTLING_ERROR`` - If the error is a throttling error
|
||||
* ``None`` - If the error is neither type of error.
|
||||
|
||||
"""
|
||||
error_code = context.get_error_code()
|
||||
op_model = context.operation_model
|
||||
if op_model is None or not op_model.error_shapes:
|
||||
return
|
||||
for shape in op_model.error_shapes:
|
||||
if shape.metadata.get('retryable') is not None:
|
||||
# Check if this error code matches the shape. This can
|
||||
# be either by name or by a modeled error code.
|
||||
error_code_to_check = (
|
||||
shape.metadata.get('error', {}).get('code') or shape.name
|
||||
)
|
||||
if error_code == error_code_to_check:
|
||||
if shape.metadata['retryable'].get('throttling'):
|
||||
return self.THROTTLING_ERROR
|
||||
return self.TRANSIENT_ERROR
|
||||
|
||||
|
||||
class ThrottlingErrorDetector:
|
||||
def __init__(self, retry_event_adapter):
|
||||
self._modeled_error_detector = ModeledRetryErrorDetector()
|
||||
self._fixed_error_code_detector = ThrottledRetryableChecker()
|
||||
self._retry_event_adapter = retry_event_adapter
|
||||
|
||||
# This expects the kwargs from needs-retry to be passed through.
|
||||
def is_throttling_error(self, **kwargs):
|
||||
context = self._retry_event_adapter.create_retry_context(**kwargs)
|
||||
if self._fixed_error_code_detector.is_retryable(context):
|
||||
return True
|
||||
error_type = self._modeled_error_detector.detect_error_type(context)
|
||||
return error_type == self._modeled_error_detector.THROTTLING_ERROR
|
||||
|
||||
|
||||
class StandardRetryConditions(BaseRetryableChecker):
|
||||
"""Concrete class that implements the standard retry policy checks.
|
||||
|
||||
Specifically:
|
||||
|
||||
not max_attempts and (transient or throttled or modeled_retry)
|
||||
|
||||
"""
|
||||
|
||||
def __init__(self, max_attempts=DEFAULT_MAX_ATTEMPTS):
|
||||
# Note: This class is for convenience so you can have the
|
||||
# standard retry condition in a single class.
|
||||
self._max_attempts_checker = MaxAttemptsChecker(max_attempts)
|
||||
self._additional_checkers = OrRetryChecker(
|
||||
[
|
||||
TransientRetryableChecker(),
|
||||
ThrottledRetryableChecker(),
|
||||
ModeledRetryableChecker(),
|
||||
OrRetryChecker(
|
||||
[
|
||||
special.RetryIDPCommunicationError(),
|
||||
special.RetryDDBChecksumError(),
|
||||
]
|
||||
),
|
||||
]
|
||||
)
|
||||
|
||||
def is_retryable(self, context):
|
||||
return self._max_attempts_checker.is_retryable(
|
||||
context
|
||||
) and self._additional_checkers.is_retryable(context)
|
||||
|
||||
|
||||
class OrRetryChecker(BaseRetryableChecker):
|
||||
def __init__(self, checkers):
|
||||
self._checkers = checkers
|
||||
|
||||
def is_retryable(self, context):
|
||||
return any(checker.is_retryable(context) for checker in self._checkers)
|
||||
|
||||
|
||||
class RetryQuotaChecker:
|
||||
_RETRY_COST = 5
|
||||
_NO_RETRY_INCREMENT = 1
|
||||
_TIMEOUT_RETRY_REQUEST = 10
|
||||
_TIMEOUT_EXCEPTIONS = (ConnectTimeoutError, ReadTimeoutError)
|
||||
|
||||
# Implementation note: We're not making this a BaseRetryableChecker
|
||||
# because this isn't just a check if we can retry. This also changes
|
||||
# state so we have to careful when/how we call this. Making it
|
||||
# a BaseRetryableChecker implies you can call .is_retryable(context)
|
||||
# as many times as you want and not affect anything.
|
||||
|
||||
def __init__(self, quota):
|
||||
self._quota = quota
|
||||
# This tracks the last amount
|
||||
self._last_amount_acquired = None
|
||||
|
||||
def acquire_retry_quota(self, context):
|
||||
if self._is_timeout_error(context):
|
||||
capacity_amount = self._TIMEOUT_RETRY_REQUEST
|
||||
else:
|
||||
capacity_amount = self._RETRY_COST
|
||||
success = self._quota.acquire(capacity_amount)
|
||||
if success:
|
||||
# We add the capacity amount to the request context so we know
|
||||
# how much to release later. The capacity amount can vary based
|
||||
# on the error.
|
||||
context.request_context['retry_quota_capacity'] = capacity_amount
|
||||
return True
|
||||
context.add_retry_metadata(RetryQuotaReached=True)
|
||||
return False
|
||||
|
||||
def _is_timeout_error(self, context):
|
||||
return isinstance(context.caught_exception, self._TIMEOUT_EXCEPTIONS)
|
||||
|
||||
# This is intended to be hooked up to ``after-call``.
|
||||
def release_retry_quota(self, context, http_response, **kwargs):
|
||||
# There's three possible options.
|
||||
# 1. The HTTP response did not have a 2xx response. In that case we
|
||||
# give no quota back.
|
||||
# 2. The HTTP request was successful and was never retried. In
|
||||
# that case we give _NO_RETRY_INCREMENT back.
|
||||
# 3. The API call had retries, and we eventually receive an HTTP
|
||||
# response with a 2xx status code. In that case we give back
|
||||
# whatever quota was associated with the last acquisition.
|
||||
if http_response is None:
|
||||
return
|
||||
status_code = http_response.status_code
|
||||
if 200 <= status_code < 300:
|
||||
if 'retry_quota_capacity' not in context:
|
||||
self._quota.release(self._NO_RETRY_INCREMENT)
|
||||
else:
|
||||
capacity_amount = context['retry_quota_capacity']
|
||||
self._quota.release(capacity_amount)
|
||||
55
Function Source Files/botocore/retries/throttling.py
Normal file
55
Function Source Files/botocore/retries/throttling.py
Normal file
@@ -0,0 +1,55 @@
|
||||
from collections import namedtuple
|
||||
|
||||
CubicParams = namedtuple('CubicParams', ['w_max', 'k', 'last_fail'])
|
||||
|
||||
|
||||
class CubicCalculator:
|
||||
_SCALE_CONSTANT = 0.4
|
||||
_BETA = 0.7
|
||||
|
||||
def __init__(
|
||||
self,
|
||||
starting_max_rate,
|
||||
start_time,
|
||||
scale_constant=_SCALE_CONSTANT,
|
||||
beta=_BETA,
|
||||
):
|
||||
self._w_max = starting_max_rate
|
||||
self._scale_constant = scale_constant
|
||||
self._beta = beta
|
||||
self._k = self._calculate_zero_point()
|
||||
self._last_fail = start_time
|
||||
|
||||
def _calculate_zero_point(self):
|
||||
scaled_value = (self._w_max * (1 - self._beta)) / self._scale_constant
|
||||
k = scaled_value ** (1 / 3.0)
|
||||
return k
|
||||
|
||||
def success_received(self, timestamp):
|
||||
dt = timestamp - self._last_fail
|
||||
new_rate = self._scale_constant * (dt - self._k) ** 3 + self._w_max
|
||||
return new_rate
|
||||
|
||||
def error_received(self, current_rate, timestamp):
|
||||
# Consider not having this be the current measured rate.
|
||||
|
||||
# We have a new max rate, which is the current rate we were sending
|
||||
# at when we received an error response.
|
||||
self._w_max = current_rate
|
||||
self._k = self._calculate_zero_point()
|
||||
self._last_fail = timestamp
|
||||
return current_rate * self._beta
|
||||
|
||||
def get_params_snapshot(self):
|
||||
"""Return a read-only object of the current cubic parameters.
|
||||
|
||||
These parameters are intended to be used for debug/troubleshooting
|
||||
purposes. These object is a read-only snapshot and cannot be used
|
||||
to modify the behavior of the CUBIC calculations.
|
||||
|
||||
New parameters may be added to this object in the future.
|
||||
|
||||
"""
|
||||
return CubicParams(
|
||||
w_max=self._w_max, k=self._k, last_fail=self._last_fail
|
||||
)
|
||||
Reference in New Issue
Block a user