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https://issues.apache.org/jira/browse/BEAM-6188?focusedWorklogId=177591&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-177591
]
ASF GitHub Bot logged work on BEAM-6188:
----------------------------------------
Author: ASF GitHub Bot
Created on: 20/Dec/18 17:00
Start Date: 20/Dec/18 17:00
Worklog Time Spent: 10m
Work Description: lgajowy commented on a change in pull request #7226:
[BEAM-6188] Unbouded synthetic source
URL: https://github.com/apache/beam/pull/7226#discussion_r243346489
##########
File path:
sdks/java/io/synthetic/src/main/java/org/apache/beam/sdk/io/synthetic/SyntheticUnboundedSource.java
##########
@@ -0,0 +1,215 @@
+/*
+ * 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.beam.sdk.io.synthetic;
+
+import com.google.common.primitives.Longs;
+import java.util.List;
+import java.util.NoSuchElementException;
+import java.util.stream.Collectors;
+import javax.annotation.Nullable;
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.coders.ByteArrayCoder;
+import org.apache.beam.sdk.coders.Coder;
+import org.apache.beam.sdk.coders.KvCoder;
+import org.apache.beam.sdk.io.UnboundedSource;
+import org.apache.beam.sdk.io.synthetic.delay.ReaderDelay;
+import org.apache.beam.sdk.options.PipelineOptions;
+import org.apache.beam.sdk.values.KV;
+import org.joda.time.Instant;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/** A {@link SyntheticUnboundedSource} that reads {@code KV<byte[], byte[]>}.
*/
+@Experimental(Experimental.Kind.SOURCE_SINK)
+public class SyntheticUnboundedSource
+ extends UnboundedSource<KV<byte[], byte[]>, SyntheticRecordsCheckpoint> {
+
+ private static final long serialVersionUID = 0;
+
+ private static final Logger LOG =
LoggerFactory.getLogger(SyntheticUnboundedSource.class);
+
+ private final SyntheticSourceOptions sourceOptions;
+
+ private final BundleSplitter bundleSplitter;
+
+ private final long startOffset;
+
+ private final long endOffset;
+
+ public SyntheticUnboundedSource(SyntheticSourceOptions sourceOptions) {
+ this(0, sourceOptions.numRecords, sourceOptions);
+ }
+
+ private SyntheticUnboundedSource(
+ long startOffset, long endOffset, SyntheticSourceOptions sourceOptions) {
+ this.sourceOptions = sourceOptions;
+ this.bundleSplitter = new BundleSplitter(sourceOptions);
+ this.startOffset = startOffset;
+ this.endOffset = endOffset;
+ }
+
+ @Override
+ public Coder<KV<byte[], byte[]>> getOutputCoder() {
+ return KvCoder.of(ByteArrayCoder.of(), ByteArrayCoder.of());
+ }
+
+ @Override
+ public void validate() {
+ super.validate();
+ sourceOptions.validate();
+ }
+
+ @Override
+ public Coder<SyntheticRecordsCheckpoint> getCheckpointMarkCoder() {
+ return SyntheticRecordsCheckpoint.CODER;
+ }
+
+ @Override
+ public UnboundedReader<KV<byte[], byte[]>> createReader(
+ PipelineOptions options, @Nullable SyntheticRecordsCheckpoint
checkpoint) {
+
+ if (checkpoint == null) {
+ return new SyntheticUnboundedReader(this);
+ } else {
+ return new SyntheticUnboundedReader(
+ new SyntheticUnboundedSource(
+ checkpoint.getStartPosition(), checkpoint.getEndPosition(),
sourceOptions));
+ }
+ }
+
+ @Override
+ public List<SyntheticUnboundedSource> split(int desiredNumSplits,
PipelineOptions options) {
+ int desiredNumBundles =
+ sourceOptions.forceNumInitialBundles != null
+ ? sourceOptions.forceNumInitialBundles
+ : desiredNumSplits;
+
+ List<SyntheticUnboundedSource> splits =
+ bundleSplitter
+ .getBundleSizes(desiredNumBundles, startOffset, endOffset)
+ .stream()
+ .map(
+ offsetRange ->
+ new SyntheticUnboundedSource(
+ offsetRange.getFrom(), offsetRange.getTo(),
sourceOptions))
+ .collect(Collectors.toList());
+ LOG.info("Split into {} bundles of sizes: {}", splits.size(), splits);
+
+ return splits;
+ }
+
+ @Override
+ public boolean requiresDeduping() {
+ return true;
+ }
+
+ private class SyntheticUnboundedReader extends UnboundedReader<KV<byte[],
byte[]>> {
+
+ private final SyntheticUnboundedSource source;
+
+ private KV<byte[], byte[]> currentKVPair;
+
+ private long currentOffset;
+
+ private Instant processingTime;
+
+ private Instant eventTime;
+
+ private SyntheticWatermark syntheticWatermark;
+
+ private ReaderDelay delay;
+
+ public SyntheticUnboundedReader(SyntheticUnboundedSource source) {
+ this.currentKVPair = null;
+ this.delay = new ReaderDelay(sourceOptions);
+ this.source = source;
+ this.currentOffset = 0;
+ this.syntheticWatermark = new SyntheticWatermark(sourceOptions);
+ }
+
+ @Override
+ public SyntheticUnboundedSource getCurrentSource() {
+ return source;
+ }
+
+ @Override
+ public KV<byte[], byte[]> getCurrent() throws NoSuchElementException {
+ if (currentKVPair == null) {
+ throw new NoSuchElementException(
+ "Current record is unavailable because either the reader is "
+ + "at the beginning of the input and start() or advance()
wasn't called, "
+ + "or the last start() or advance() returned false.");
+ }
+ return currentKVPair;
+ }
+
+ @Override
+ public Instant getCurrentTimestamp() throws NoSuchElementException {
+ if (eventTime == null) {
+ throw new NoSuchElementException(
+ "Current timestamp is unavailable because either the reader is "
+ + "at the beginning of the input and start() or advance()
wasn't called, "
+ + "or the last start() or advance() returned false.");
+ }
+ return eventTime;
+ }
+
+ @Override
+ public boolean start() {
+ currentOffset = SyntheticUnboundedSource.this.startOffset;
+ delay.delayStart(currentOffset);
+ return advance();
+ }
+
+ @Override
+ public boolean advance() {
+ currentOffset++;
+
+ processingTime = new Instant();
+ eventTime =
processingTime.minus(sourceOptions.nextProcessingTimeDelay(currentOffset));
+
+ SyntheticSourceOptions.Record record =
+ getCurrentSource().sourceOptions.genRecord(currentOffset);
+ currentKVPair = record.kv;
+
+ delay.delayRecord(record);
+
+ return currentOffset < source.endOffset;
Review comment:
I investigated today and unfortunately, this won't be enough for streaming
scenarios. In order to stop the pipeline (with DONE state) after all records
are generated we need to do something like Nexmark does:
```
if(currentOffset >= source.endOffset) {
watermark = BoundedWindow.TIMESTAMP_MAX_VALUE;
return false;
} else {
return true;
}
```
Thanks to this the pipeline won't hang infinitely waiting for new records.
I'm going to extend this PR with those changes tomorrow but giving a heads up
in case you want to provide some feedback about this.
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Issue Time Tracking
-------------------
Worklog Id: (was: 177591)
Time Spent: 3h (was: 2h 50m)
> Create unbounded synthetic source
> ---------------------------------
>
> Key: BEAM-6188
> URL: https://issues.apache.org/jira/browse/BEAM-6188
> Project: Beam
> Issue Type: Sub-task
> Components: testing
> Reporter: Lukasz Gajowy
> Assignee: Lukasz Gajowy
> Priority: Major
> Time Spent: 3h
> Remaining Estimate: 0h
>
> It is needed for streaming scenarios. It should provide ways to reason about
> time and recovering from checkpoints.
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