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https://issues.apache.org/jira/browse/BEAM-8537?focusedWorklogId=371338&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-371338
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ASF GitHub Bot logged work on BEAM-8537:
----------------------------------------
Author: ASF GitHub Bot
Created on: 14/Jan/20 03:57
Start Date: 14/Jan/20 03:57
Worklog Time Spent: 10m
Work Description: boyuanzz commented on pull request #10375: [BEAM-8537]
Provide WatermarkEstimator to track watermark
URL: https://github.com/apache/beam/pull/10375#discussion_r366142878
##########
File path: sdks/python/apache_beam/runners/common.py
##########
@@ -495,6 +525,162 @@ def invoke_process(self,
windowed_value, self.process_method(windowed_value.value))
+class _ThreadsafeWatermarkEstimator(object):
+ """A threadsafe wrapper which wraps a WatermarkEstimator with locking
+ mechanism to guarantee multi-thread safety.
+ """
+ def __init__(self, watermark_estimator, lock):
+ if not isinstance(watermark_estimator, iobase.WatermarkEstimator):
+ raise ValueError('Initializing Threadsafe requires a WatermarkEstimator')
+ self._watermark_estimator = watermark_estimator
+ self._lock = lock
+
+ def __getattr__(self, attr):
+ if hasattr(self._watermark_estimator, attr):
+ def method_wrapper(*args, **kw):
+ with self._lock:
+ return getattr(self._watermark_estimator, attr)(*args, **kw)
+ return method_wrapper
+ raise AttributeError(attr)
+
+ def get_estimator_state(self):
+ # The caller should hold the lock before entering this function.
+ return self._watermark_estimator.get_estimator_state()
+
+ def current_watermark(self):
+ # The caller should hold the lock before entering this function.
+ return self._watermark_estimator.current_watermark()
+
+ def observe_timestamp(self, timestamp):
+ if not isinstance(timestamp, Timestamp):
+ raise ValueError('Input of observe_timestamp should be a Timestamp '
+ 'object')
+ with self._lock:
+ self._watermark_estimator.observe_timestamp(timestamp)
+
+
+class _ThreadsafeRestrictionTracker(object):
+ """A thread-safe wrapper which wraps a `RestritionTracker`.
+
+ This wrapper guarantees synchronization of modifying restrictions across
+ multi-thread.
+ """
+
+ def __init__(self, restriction_tracker, lock):
+ if not isinstance(restriction_tracker, iobase.RestrictionTracker):
+ raise ValueError(
+ 'Initialize ThreadsafeRestrictionTracker requires'
+ 'RestrictionTracker.')
+ self._restriction_tracker = restriction_tracker
+ # Records an absolute timestamp when defer_remainder is called.
+ self._deferred_timestamp = None
+ self._lock = lock
+ self._deferred_residual = None
+ self._deferred_watermark = None
+
+ def current_restriction(self):
+ with self._lock:
+ return self._restriction_tracker.current_restriction()
+
+ def try_claim(self, position):
+ with self._lock:
+ return self._restriction_tracker.try_claim(position)
+
+ def defer_remainder(self, deferred_time=None):
+ """Performs self-checkpoint on current processing restriction with an
+ expected resuming time.
+
+ Self-checkpoint could happen during processing elements. When executing an
+ DoFn.process(), you may want to stop processing an element and resuming
+ later if current element has been processed quit a long time or you also
+ want to have some outputs from other elements. ``defer_remainder()`` can be
+ called on per element if needed.
+
+ Args:
+ deferred_time: A relative ``Duration`` that indicates the ideal time gap
+ between now and resuming, or an absolute ``Timestamp`` for resuming
+ execution time. If the time_delay is None, the deferred work will be
+ executed as soon as possible.
+ """
+
+ # Record current time for calculating deferred_time later.
+ self._deferred_timestamp = Timestamp.now()
+ if (deferred_time and
+ not isinstance(deferred_time, Duration) and
+ not isinstance(deferred_time, Timestamp)):
+ raise ValueError('The timestamp of deter_remainder() should be a '
+ 'Duration or a Timestamp, or None.')
+ self._deferred_watermark = deferred_time
+ checkpoint = self.try_split(0)
+ if checkpoint:
+ _, self._deferred_residual = checkpoint
+
+ def check_done(self):
+ with self._lock:
+ return self._restriction_tracker.check_done()
+
+ def current_progress(self):
+ with self._lock:
+ return self._restriction_tracker.current_progress()
+
+ def try_split(self, fraction_of_remainder):
+ # The caller should hold the lock before entering this function.
Review comment:
Thanks! Changed it to `raise RuntimeError`
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Issue Time Tracking
-------------------
Worklog Id: (was: 371338)
Time Spent: 5h 40m (was: 5.5h)
> Provide WatermarkEstimatorProvider for different types of WatermarkEstimator
> ----------------------------------------------------------------------------
>
> Key: BEAM-8537
> URL: https://issues.apache.org/jira/browse/BEAM-8537
> Project: Beam
> Issue Type: Improvement
> Components: sdk-py-core, sdk-py-harness
> Reporter: Boyuan Zhang
> Assignee: Boyuan Zhang
> Priority: Major
> Time Spent: 5h 40m
> Remaining Estimate: 0h
>
> This is a follow up for in-progress PR:
> https://github.com/apache/beam/pull/9794.
> Current implementation in PR9794 provides a default implementation of
> WatermarkEstimator. For further work, we want to let WatermarkEstimator to be
> a pure Interface. We'll provide a WatermarkEstimatorProvider to be able to
> create a custom WatermarkEstimator per windowed value. It should be similar
> to how we track restriction for SDF:
> WatermarkEstimator <---> RestrictionTracker
> WatermarkEstimatorProvider <---> RestrictionTrackerProvider
> WatermarkEstimatorParam <---> RestrictionDoFnParam
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