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https://issues.apache.org/jira/browse/APEXMALHAR-2085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15351837#comment-15351837
]
ASF GitHub Bot commented on APEXMALHAR-2085:
--------------------------------------------
Github user chinmaykolhatkar commented on a diff in the pull request:
https://github.com/apache/apex-malhar/pull/319#discussion_r68658531
--- Diff:
library/src/main/java/org/apache/apex/malhar/lib/window/impl/AbstractWindowedOperator.java
---
@@ -0,0 +1,490 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.apex.malhar.lib.window.impl;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+import javax.validation.ValidationException;
+
+import org.joda.time.Duration;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.apex.malhar.lib.window.Accumulation;
+import org.apache.apex.malhar.lib.window.ControlTuple;
+import org.apache.apex.malhar.lib.window.TriggerOption;
+import org.apache.apex.malhar.lib.window.Tuple;
+import org.apache.apex.malhar.lib.window.Window;
+import org.apache.apex.malhar.lib.window.WindowOption;
+import org.apache.apex.malhar.lib.window.WindowState;
+import org.apache.apex.malhar.lib.window.WindowedOperator;
+import org.apache.apex.malhar.lib.window.WindowedStorage;
+import org.apache.hadoop.classification.InterfaceStability;
+
+import com.google.common.base.Function;
+
+import com.datatorrent.api.Context;
+import com.datatorrent.api.DefaultInputPort;
+import com.datatorrent.api.DefaultOutputPort;
+import com.datatorrent.api.annotation.InputPortFieldAnnotation;
+import com.datatorrent.common.util.BaseOperator;
+
+/**
+ * This is the abstract windowed operator class that implements most of
the windowing, triggering, and accumulating
+ * concepts. The subclass of this abstract class is supposed to provide
the implementation of how the accumulated
+ * values are stored in the storage.
+ *
+ * @param <InputT> The type of the input tuple
+ * @param <OutputT> The type of the output tuple
+ * @param <DataStorageT> The type of the data storage
+ * @param <AccumulationT> The type of the accumulation
+ */
[email protected]
+public abstract class AbstractWindowedOperator<InputT, OutputT,
DataStorageT extends WindowedStorage, AccumulationT extends Accumulation>
+ extends BaseOperator implements WindowedOperator<InputT>
+{
+
+ protected WindowOption windowOption;
+ protected TriggerOption triggerOption;
+ protected long allowedLatenessMillis = -1;
+ protected WindowedStorage<WindowState> windowStateMap;
+
+ private Function<InputT, Long> timestampExtractor;
+
+ private long currentWatermark;
+ private boolean triggerAtWatermark;
+ private long earlyTriggerCount;
+ private long earlyTriggerMillis;
+ private long lateTriggerCount;
+ private long lateTriggerMillis;
+ private long currentDerivedTimestamp = -1;
+ private long windowWidthMillis;
+ protected DataStorageT dataStorage;
+ protected DataStorageT retractionStorage;
+ protected AccumulationT accumulation;
+
+ private static final transient Logger LOG =
LoggerFactory.getLogger(AbstractWindowedOperator.class);
+
+ public final transient DefaultInputPort<Tuple<InputT>> input = new
DefaultInputPort<Tuple<InputT>>()
+ {
+ @Override
+ public void process(Tuple<InputT> tuple)
+ {
+ processTuple(tuple);
+ }
+ };
+
+ // TODO: This port should be removed when Apex Core has native support
for custom control tuples
+ @InputPortFieldAnnotation(optional = true)
+ public final transient DefaultInputPort<ControlTuple> controlInput = new
DefaultInputPort<ControlTuple>()
+ {
+ @Override
+ public void process(ControlTuple tuple)
+ {
+ if (tuple instanceof ControlTuple.Watermark) {
+ processWatermark((ControlTuple.Watermark)tuple);
+ }
+ }
+ };
+
+
+ // TODO: multiple input ports for join operations
+
+ public final transient DefaultOutputPort<Tuple<OutputT>> output = new
DefaultOutputPort<>();
+
+ // TODO: This port should be removed when Apex Core has native support
for custom control tuples
+ public final transient DefaultOutputPort<ControlTuple> controlOutput =
new DefaultOutputPort<>();
+
+ /**
+ * Process the incoming data tuple
+ *
+ * @param tuple
+ */
+ public void processTuple(Tuple<InputT> tuple)
+ {
+ long timestamp = extractTimestamp(tuple);
+ if (isTooLate(timestamp)) {
+ dropTuple(tuple);
+ } else {
+ Tuple.WindowedTuple<InputT> windowedTuple = getWindowedValue(tuple);
+ // do the accumulation
+ accumulateTuple(windowedTuple);
+
+ for (Window window : windowedTuple.getWindows()) {
+ WindowState windowState = windowStateMap.get(window);
+ windowState.tupleCount++;
+ // process any count based triggers
+ if (windowState.watermarkArrivalTime == -1) {
+ // watermark has not arrived yet, check for early count based
trigger
+ if (earlyTriggerCount > 0 && (windowState.tupleCount %
earlyTriggerCount) == 0) {
+ fireTrigger(window, windowState);
+ }
+ } else {
+ // watermark has arrived, check for late count based trigger
+ if (lateTriggerCount > 0 && (windowState.tupleCount %
lateTriggerCount) == 0) {
+ fireTrigger(window, windowState);
+ }
+ }
+ }
+ }
+ }
+
+ @Override
+ public void setWindowOption(WindowOption windowOption)
+ {
+ this.windowOption = windowOption;
+ if (this.windowOption instanceof WindowOption.GlobalWindow) {
+ windowStateMap.put(Window.GLOBAL_WINDOW, new WindowState());
+ }
+ }
+
+ @Override
+ public void setTriggerOption(TriggerOption triggerOption)
+ {
+ this.triggerOption = triggerOption;
+ for (TriggerOption.Trigger trigger : triggerOption.getTriggerList()) {
+ switch (trigger.getWatermarkOpt()) {
+ case ON_TIME:
+ triggerAtWatermark = true;
+ break;
+ case EARLY:
+ if (trigger instanceof TriggerOption.TimeTrigger) {
+ earlyTriggerMillis =
((TriggerOption.TimeTrigger)trigger).getDuration().getMillis();
+ } else if (trigger instanceof TriggerOption.CountTrigger) {
+ earlyTriggerCount =
((TriggerOption.CountTrigger)trigger).getCount();
+ }
+ break;
+ case LATE:
+ if (trigger instanceof TriggerOption.TimeTrigger) {
+ lateTriggerMillis =
((TriggerOption.TimeTrigger)trigger).getDuration().getMillis();
+ } else if (trigger instanceof TriggerOption.CountTrigger) {
+ lateTriggerCount =
((TriggerOption.CountTrigger)trigger).getCount();
+ }
+ break;
+ default:
+ throw new RuntimeException("Unexpected watermark option: " +
trigger.getWatermarkOpt());
+ }
+ }
+ }
+
+ @Override
+ public void setAllowedLateness(Duration allowedLateness)
+ {
+ this.allowedLatenessMillis = allowedLateness.getMillis();
+ }
+
+ /**
+ * This method sets the storage for the data for each window
+ *
+ * @param storageAgent
+ */
+ public void setDataStorage(DataStorageT storageAgent)
+ {
+ this.dataStorage = storageAgent;
+ }
+
+ /**
+ * This method sets the storage for the retraction data for each window.
Only used when the accumulation mode is ACCUMULATING_AND_RETRACTING
+ *
+ * @param storageAgent
+ */
+ public void setRetractionStorage(DataStorageT storageAgent)
+ {
+ this.retractionStorage = storageAgent;
+ }
+
+ /**
+ * Sets the accumulation, which basically tells the WindowedOperator
what to do if a new tuple comes in and what
+ * to put in the pane when a trigger is fired
+ *
+ * @param accumulation
+ */
+ public void setAccumulation(AccumulationT accumulation)
+ {
+ this.accumulation = accumulation;
+ }
+
+ @Override
+ public void setWindowStateStorage(WindowedStorage<WindowState>
storageAgent)
+ {
+ this.windowStateMap = storageAgent;
+ }
+
+ @Override
+ public void setTimestampExtractor(Function<InputT, Long>
timestampExtractor)
+ {
+ this.timestampExtractor = timestampExtractor;
+ }
+
+ public void validate() throws ValidationException
+ {
+ if (accumulation == null) {
+ throw new ValidationException("Accumulation must be set");
+ }
+ if (dataStorage == null) {
+ throw new ValidationException("Data storage must be set");
+ }
+ if (windowStateMap == null) {
+ throw new ValidationException("Window state storage must be set");
+ }
+ if (triggerOption != null) {
+ if (triggerOption.isFiringOnlyUpdatedPanes()) {
+ if (retractionStorage == null) {
+ throw new ValidationException("A retraction storage is required
for firingOnlyUpdatedPanes option");
+ }
+ if (triggerOption.getAccumulationMode() ==
TriggerOption.AccumulationMode.DISCARDING) {
+ throw new ValidationException("DISCARDING accumulation mode is
not valid for firingOnlyUpdatedPanes option");
+ }
+ }
+ if (triggerOption.getAccumulationMode() ==
TriggerOption.AccumulationMode.ACCUMULATING_AND_RETRACTING &&
+ retractionStorage == null) {
+ throw new ValidationException("A retraction storage is required
for ACCUMULATING_AND_RETRACTING accumulation mode");
+ }
+ }
+ }
+
+ @Override
+ public Tuple.WindowedTuple<InputT> getWindowedValue(Tuple<InputT> input)
+ {
+ Tuple.WindowedTuple<InputT> windowedTuple = new
Tuple.WindowedTuple<>();
+ windowedTuple.setValue(input.getValue());
+ windowedTuple.setTimestamp(extractTimestamp(input));
+ assignWindows(windowedTuple.getWindows(), input);
+ return windowedTuple;
+ }
+
+ private long extractTimestamp(Tuple<InputT> tuple)
+ {
+ if (timestampExtractor == null) {
+ if (tuple instanceof Tuple.TimestampedTuple) {
+ return ((Tuple.TimestampedTuple)tuple).getTimestamp();
+ } else {
+ return 0;
+ }
+ } else {
+ return timestampExtractor.apply(tuple.getValue());
+ }
+ }
+
+ private void assignWindows(List<Window> windows, Tuple<InputT>
inputTuple)
+ {
+ if (windowOption instanceof WindowOption.GlobalWindow) {
+ windows.add(Window.GLOBAL_WINDOW);
+ } else {
+ long timestamp = extractTimestamp(inputTuple);
+ if (windowOption instanceof WindowOption.TimeWindows) {
+
+ for (Window.TimeWindow window :
getTimeWindowsForTimestamp(timestamp)) {
+ if (!windowStateMap.containsWindow(window)) {
+ windowStateMap.put(window, new WindowState());
+ }
+ windows.add(window);
+ }
+ } else if (windowOption instanceof WindowOption.SessionWindows) {
+ assignSessionWindows(windows, timestamp, inputTuple);
+ }
+ }
+ }
+
+ protected void assignSessionWindows(List<Window> windows, long
timestamp, Tuple<InputT> inputTuple)
+ {
+ throw new UnsupportedOperationException();
+ }
+
+ /**
+ * Returns the list of windows TimeWindows for the given timestamp.
+ * If we are doing sliding windows, this will return multiple windows.
Otherwise, only one window will be returned.
+ * Note that this method does not apply to SessionWindows.
+ *
+ * @param timestamp
+ * @return
+ */
+ private List<Window.TimeWindow> getTimeWindowsForTimestamp(long
timestamp)
+ {
+ List<Window.TimeWindow> windows = new ArrayList<>();
+ if (windowOption instanceof WindowOption.TimeWindows) {
+ long durationMillis =
((WindowOption.TimeWindows)windowOption).getDuration().getMillis();
+ long beginTimestamp = timestamp - timestamp % durationMillis;
+ windows.add(new Window.TimeWindow(beginTimestamp, durationMillis));
+ if (windowOption instanceof WindowOption.SlidingTimeWindows) {
+ long slideBy =
((WindowOption.SlidingTimeWindows)windowOption).getSlideByDuration().getMillis();
+ // add the sliding windows front and back
+ // Note: this messes up the order of the window and we might want
to revisit this if the order of the windows
+ // matter
+ for (long slideBeginTimestamp = beginTimestamp - slideBy;
+ slideBeginTimestamp <= timestamp && timestamp <
slideBeginTimestamp + durationMillis;
+ slideBeginTimestamp -= slideBy) {
+ windows.add(new Window.TimeWindow(slideBeginTimestamp,
durationMillis));
+ }
+ for (long slideBeginTimestamp = beginTimestamp + slideBy;
+ slideBeginTimestamp <= timestamp && timestamp <
slideBeginTimestamp + durationMillis;
+ slideBeginTimestamp += slideBy) {
+ windows.add(new Window.TimeWindow(slideBeginTimestamp,
durationMillis));
+ }
+ }
+ } else {
+ throw new IllegalStateException("Unexpected WindowOption");
+ }
+ return windows;
+ }
+
+ @Override
+ public boolean isTooLate(long timestamp)
+ {
+ return allowedLatenessMillis < 0 ? false : (timestamp <
currentWatermark - allowedLatenessMillis);
+ }
+
+ @Override
+ public void dropTuple(Tuple<InputT> input)
+ {
+ // do nothing
+ LOG.debug("Dropping late tuple {}", input);
+ }
+
+
+ @Override
+ public void processWatermark(ControlTuple.Watermark watermark)
+ {
+ currentWatermark = watermark.getTimestamp();
+ long horizon = currentWatermark - allowedLatenessMillis;
+ if (allowedLatenessMillis >= 0) {
+ // purge window that are too late to accept any more input
+ dataStorage.removeUpTo(horizon);
+ }
+
+ for (Iterator<Map.Entry<Window, WindowState>> it =
windowStateMap.iterator(); it.hasNext(); ) {
+ Map.Entry<Window, WindowState> entry = it.next();
+ Window window = entry.getKey();
+ WindowState windowState = entry.getValue();
+ if (allowedLatenessMillis >= 0 && window.getBeginTimestamp() +
window.getDurationMillis() < horizon) {
+ // discard this window because it's too late now
+ it.remove();
+ } else if (window.getBeginTimestamp() + window.getDurationMillis() <
currentWatermark) {
+ // watermark has not arrived for this window before, marking this
window late
+ if (windowState.watermarkArrivalTime == -1) {
+ windowState.watermarkArrivalTime = currentDerivedTimestamp;
+ if (triggerAtWatermark) {
--- End diff --
Shouldn't triggerAtWatermark be a default option?
As per beam specification, trigger at watermark always happens.
> Implement Windowed Operators
> ----------------------------
>
> Key: APEXMALHAR-2085
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-2085
> Project: Apache Apex Malhar
> Issue Type: New Feature
> Reporter: Siyuan Hua
> Assignee: David Yan
>
> As per our recent several discussions in the community. A group of Windowed
> Operators that delivers the window semantic follows the google Data Flow
> model(https://cloud.google.com/dataflow/) is very important.
> The operators should be designed and implemented in a way for
> High-level API
> Beam translation
> Easy to use with other popular operator
> {panel:title=Operator Hierarchy}
> Hierarchy of the operators,
> The windowed operators should cover all possible transformations that require
> window, and batch processing is also considered as special window called
> global window
> {code}
> +-------------------+
> +---------> | WindowedOperator | <--------+
> | +--------+----------+ |
> | ^ ^--------------------------------+
> | | | |
> | | | |
> +------+--------+ +------+------+ +-------+-----+ +------+-----+
> |CombineOperator| |GroupOperator| |KeyedOperator| |JoinOperator|
> +---------------+ +-------------+ +------+------+ +-----+------+
> +---------^ ^ ^
> | | |
> +--------+---+ +-----+----+ +----+----+
> |KeyedCombine| |KeyedGroup| | CoGroup |
> +------------+ +----------+ +---------+
> {code}
> Combine operation includes all operations that combine all tuples in one
> window into one or small number of tuples, Group operation group all tuples
> in one window, Join and CoGroup are used to join and group tuples from
> different inputs.
> {panel}
> {panel:title=Components}
> * Window Component
> It includes configuration, window state that should be checkpointed, etc. It
> should support NonMergibleWindow(fixed or slide) MergibleWindow(Session)
> * Trigger
> It should support early trigger, late trigger with customizable trigger
> behaviour
> * Other related components:
> ** Watermark generator, can be plugged into input source to generate watermark
> ** Tuple schema support:
> It should handle either predefined tuple type or give a declarative API to
> describe the user defined tuple class
> {panel}
> Most component API should be reused in High-Level API
> This is the umbrella ticket, separate tickets would be created for different
> components and operators respectively
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