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https://issues.apache.org/jira/browse/APEXMALHAR-1701?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15403872#comment-15403872
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ASF GitHub Bot commented on APEXMALHAR-1701:
--------------------------------------------
Github user chinmaykolhatkar commented on a diff in the pull request:
https://github.com/apache/apex-malhar/pull/335#discussion_r73142681
--- Diff:
library/src/main/java/org/apache/apex/malhar/lib/dedup/AbstractDeduper.java ---
@@ -0,0 +1,459 @@
+/**
+ * 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.dedup;
+
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+
+import javax.validation.constraints.NotNull;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import org.apache.apex.malhar.lib.state.BucketedState;
+import
org.apache.apex.malhar.lib.state.managed.ManagedTimeUnifiedStateImpl;
+import org.apache.apex.malhar.lib.state.managed.TimeBucketAssigner;
+import org.apache.hadoop.classification.InterfaceStability.Evolving;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Maps;
+import com.google.common.util.concurrent.Futures;
+
+import com.datatorrent.api.AutoMetric;
+import com.datatorrent.api.Context;
+import com.datatorrent.api.Context.OperatorContext;
+import com.datatorrent.api.DAG;
+import com.datatorrent.api.DefaultInputPort;
+import com.datatorrent.api.DefaultOutputPort;
+import com.datatorrent.api.Operator;
+import com.datatorrent.api.Operator.ActivationListener;
+import com.datatorrent.api.annotation.OperatorAnnotation;
+import com.datatorrent.lib.fileaccess.FileAccessFSImpl;
+import com.datatorrent.lib.fileaccess.TFileImpl;
+import com.datatorrent.netlet.util.Slice;
+
+/**
+ * Abstract class which allows de-duplicating incoming tuples based on a
configured key.
+ * Also supports expiry mechanism based on a configurable expiry period
configured using {@link TimeBucketAssigner}
+ * in {@link ManagedTimeUnifiedStateImpl}
+ * Following steps are used in identifying the state of a particular tuple:
+ * 1. Check if the time of the tuple falls in an expired bucket. If so,
the tuple is expired
+ * 2. If the tuple is a valid event, it is checked in the store whether
the same key already exists in the
+ * time bucket identified by the event time. If, so, the tuple is a
duplicate.
+ * 3. Otherwise the tuple is a unique tuple.
+ *
+ * @param <T> type of events
+ */
+@Evolving
+@OperatorAnnotation(checkpointableWithinAppWindow = false)
+public abstract class AbstractDeduper<T>
+ implements Operator, Operator.IdleTimeHandler,
ActivationListener<Context>, Operator.CheckpointNotificationListener
+{
+ /**
+ * The input port on which events are received.
+ */
+ public final transient DefaultInputPort<T> input = new
DefaultInputPort<T>()
+ {
+ @Override
+ public final void process(T tuple)
+ {
+ processTuple(tuple);
+ }
+ };
+
+ /**
+ * The output port on which deduped events are emitted.
+ */
+ public final transient DefaultOutputPort<T> unique = new
DefaultOutputPort<>();
+
+ /**
+ * The output port on which duplicate events are emitted.
+ */
+ public final transient DefaultOutputPort<T> duplicate = new
DefaultOutputPort<>();
+
+ /**
+ * The output port on which expired events are emitted.
+ */
+ public final transient DefaultOutputPort<T> expired = new
DefaultOutputPort<>();
+
+ /**
+ * Whether or not the order of tuples be maintained.
+ * Making this "true" might entail some cost in performance, but makes
the operator idempotent.
+ */
+ private boolean preserveTupleOrder = true;
+
+ @NotNull
+ protected final ManagedTimeUnifiedStateImpl managedState = new
ManagedTimeUnifiedStateImpl();
+
+ /**
+ * Map to hold the result of a tuple processing (unique, duplicate,
expired or error) until previous
+ * tuples get processed. This is used only when {@link
#preserveTupleOrder} is true.
+ */
+ private transient Map<T, Decision> decisions;
+ private transient long sleepMillis;
+ private transient Map<T, Future<Slice>> waitingEvents =
Maps.newLinkedHashMap();
+ private transient Map<Slice, Long> asyncEvents = Maps.newLinkedHashMap();
+
+ // Metrics
+ @AutoMetric
+ private transient long uniqueEvents;
+ @AutoMetric
+ private transient long duplicateEvents;
+ @AutoMetric
+ private transient long expiredEvents;
+
+ @Override
+ public void setup(OperatorContext context)
+ {
+ sleepMillis = context.getValue(Context.OperatorContext.SPIN_MILLIS);
+ FileAccessFSImpl fAccessImpl = new TFileImpl.DTFileImpl();
+ fAccessImpl.setBasePath(context.getValue(DAG.APPLICATION_PATH) +
"/bucket_data");
+ managedState.setFileAccess(fAccessImpl);
+ managedState.setup(context);
+
+ if (preserveTupleOrder) {
+ decisions = Maps.newLinkedHashMap();
+ }
+ }
+
+ @Override
+ public void beginWindow(long l)
+ {
+ // Reset Metrics
+ uniqueEvents = 0;
+ duplicateEvents = 0;
+ expiredEvents = 0;
+
+ managedState.beginWindow(l);
+ }
+
+ protected abstract Slice getKey(T event);
+
+ protected abstract long getTime(T event);
+
+ /**
+ * Processes an incoming tuple
+ *
+ * @param tuple
+ */
+ protected void processTuple(T tuple)
+ {
+
+ long time = getTime(tuple);
+ Future<Slice> valFuture = managedState.getAsync(time, getKey(tuple));
+
+ if (valFuture.isDone()) {
+ try {
+ processEvent(tuple, valFuture.get());
+ } catch (InterruptedException | ExecutionException e) {
+ throw new RuntimeException(e);
+ }
+ } else {
+ processWaitingEvent(tuple, valFuture);
+ }
+ }
+
+ /**
+ * Processes a looked-up event
+ *
+ * @param tuple
+ * @param value
+ */
+ protected void processEvent(T tuple, Slice value)
+ {
+ if (value == BucketedState.EXPIRED) {
+ processInvalid(tuple);
+ return;
+ }
+ processValid(tuple, value);
+ }
+
+ /**
+ * Processes a tuple which is waiting for the lookup to return.
+ *
+ * @param tuple The tuple which needs to wait
+ * @param future The future object which will ultimately return the
lookup result
+ */
+ protected void processWaitingEvent(T tuple, Future<Slice> future)
+ {
+ waitingEvents.put(tuple, future);
+ if (preserveTupleOrder) {
+ recordDecision(tuple, Decision.UNKNOWN);
+ }
+ }
+
+ /**
+ * Processes a valid (non-expired) tuple. This tuple may be a unique or
a duplicate.
+ *
+ * @param tuple
+ * The tuple to be processed
+ * @param value
+ * Looked up key of the tuple
+ */
+ protected void processValid(T tuple, Slice value)
+ {
+ if (!preserveTupleOrder || waitingEvents.isEmpty()) {
+ if (value == null) {
+ managedState.put(getTime(tuple), getKey(tuple), getKey(tuple));
+ processUnique(tuple);
+ } else {
+ processDuplicate(tuple);
+ }
+ } else {
+ processWaitingEvent(tuple, Futures.immediateFuture(value));
+ }
+ }
+
+ /**
+ * Processes invalid tuples.
+ *
+ * @param tuple
+ */
+ protected void processInvalid(T tuple)
+ {
+ if (preserveTupleOrder && !decisions.isEmpty()) {
+ recordDecision(tuple, Decision.EXPIRED);
+ } else {
+ processExpired(tuple);
+ }
+ }
+
+ /**
+ * Processes an expired tuple
+ *
+ * @param tuple
+ */
+ protected void processExpired(T tuple)
+ {
+ expiredEvents++;
+ emitExpired(tuple);
+ }
+
+ /**
+ * Processes the duplicate tuple.
+ *
+ * @param tuple
+ * The tuple which is a duplicate
+ */
+ protected void processDuplicate(T tuple)
+ {
+ if (preserveTupleOrder && !decisions.isEmpty()) {
+ recordDecision(tuple, Decision.DUPLICATE);
+ } else {
+ duplicateEvents++;
+ emitDuplicate(tuple);
+ }
+ }
+
+ /**
+ * Processes the unique tuple.
+ *
+ * @param tuple
+ * The tuple which is a unique
+ */
+ protected void processUnique(T tuple)
+ {
+ if (preserveTupleOrder && !decisions.isEmpty()) {
+ recordDecision(tuple, Decision.UNIQUE);
+ } else {
+ uniqueEvents++;
+ emitUnique(tuple);
+ }
+ }
+
+ /**
+ * {@inheritDoc}
+ */
+ @Override
+ public void handleIdleTime()
+ {
+ if (preserveTupleOrder) {
+ emitProcessedTuples();
+ }
+ processAuxiliary(false);
+ }
+
+ /**
+ * Does any auxiliary processing in the idle time of the operator.
+ * Processes any tuples which are waiting for the lookup to return.
+ *
+ * @param finalize Whether or not to wait for future to return
+ */
+ protected void processAuxiliary(boolean finalize)
+ {
+ if (waitingEvents.size() > 0) {
+ Iterator<Map.Entry<T, Future<Slice>>> waitIterator =
waitingEvents.entrySet().iterator();
+ while (waitIterator.hasNext()) {
+ Map.Entry<T, Future<Slice>> waitingEvent = waitIterator.next();
+ T tuple = waitingEvent.getKey();
+ Slice tupleKey = getKey(tuple);
+ long tupleTime = getTime(tuple);
+ Future<Slice> future = waitingEvent.getValue();
+ if (future.isDone() || finalize ) {
+ try {
+ if (future.get() == null && asyncEvents.get(tupleKey) == null)
{
+ managedState.put(tupleTime, tupleKey, tupleKey);
+ asyncEvents.put(tupleKey, tupleTime);
+ processUnique(tuple);
+ } else {
+ processDuplicate(tuple);
+ }
+ } catch (InterruptedException | ExecutionException e) {
+ throw new RuntimeException("handle idle time", e);
+ }
+ waitIterator.remove();
+ }
+ }
+ }
+ }
+
+ @Override
+ public void endWindow()
+ {
+ processAuxiliary(true);
+ if (preserveTupleOrder) {
+ emitProcessedTuples();
+ }
+ Preconditions.checkArgument(waitingEvents.isEmpty());
+ asyncEvents.clear();
+ managedState.endWindow();
+ }
+
+ /**
+ * Records a decision for use later. This is needed to ensure that the
order of incoming tuples is maintained.
+ *
+ * @param tuple
+ * @param d The decision for the tuple
+ */
+ protected void recordDecision(T tuple, Decision d)
+ {
+ decisions.put(tuple, d);
+ }
+
+ /**
+ * Processes tuples for which the decision (unique / duplicate /
expired) has been made.
+ * Breaks once an undecided tuple is found, as we don't want to emit out
of order
+ */
+ protected void emitProcessedTuples()
+ {
+ Iterator<Entry<T, Decision>> entries = decisions.entrySet().iterator();
+ while (entries.hasNext()) {
+ Entry<T, Decision> td = entries.next();
+ switch (td.getValue()) {
+ case UNIQUE:
+ uniqueEvents++;
+ emitUnique(td.getKey());
+ entries.remove();
+ break;
+ case DUPLICATE:
+ duplicateEvents++;
+ emitDuplicate(td.getKey());
+ entries.remove();
+ break;
+ case EXPIRED:
+ expiredEvents++;
+ emitExpired(td.getKey());
+ entries.remove();
+ break;
+ default:
+ /*
+ * Decision for this is still UNKNOWN. Tuple is still waiting
for bucket to be loaded. Break.
+ */
+ break;
+ }
+ }
+ }
+
+ @Override
+ public void teardown()
+ {
+ managedState.teardown();
+ }
+
+ @Override
+ public void beforeCheckpoint(long windowId)
+ {
+ managedState.beforeCheckpoint(windowId);
+ }
+
+ @Override
+ public void checkpointed(long windowId)
+ {
+ managedState.checkpointed(windowId);
+ }
+
+ @Override
+ public void committed(long windowId)
+ {
+ managedState.committed(windowId);
+ }
+
+ protected void emitUnique(T event)
+ {
+ unique.emit(event);
+ }
+
+ protected void emitDuplicate(T event)
+ {
+ duplicate.emit(event);
+ }
+
+ protected void emitExpired(T event)
+ {
+ expired.emit(event);
+ }
+
+ /**
+ * Checks whether output of deduper should preserve the input order
+ */
+ public boolean isOrderedOutput()
+ {
+ return preserveTupleOrder;
+ }
+
+ /**
+ * If set to true, the deduper will emit tuples in the order in which
they were received. Tuples which arrived later
+ * will wait for previous tuples to get processed and emitted. If not
set, the order of tuples may change as tuples
+ * may be emitted out of order as and when they get processed.
+ *
+ * @param orderedOutput
--- End diff --
Incorrect param in javadoc. Also add description to it.
> Deduper : create a deduper backed by Managed State
> --------------------------------------------------
>
> Key: APEXMALHAR-1701
> URL: https://issues.apache.org/jira/browse/APEXMALHAR-1701
> Project: Apache Apex Malhar
> Issue Type: Task
> Components: algorithms
> Reporter: Chandni Singh
> Assignee: Chandni Singh
>
> Need a de-deduplicator operator that is based on Managed State.
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