/*
* Copyright 2012-2016 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.
*/
import java.nio.charset.CharacterCodingException;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.InvalidStateException;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.ShutdownException;
import com.amazonaws.services.kinesis.clientlibrary.exceptions.ThrottlingException;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessor;
import com.amazonaws.services.kinesis.clientlibrary.interfaces.IRecordProcessorCheckpointer;
import com.amazonaws.services.kinesis.clientlibrary.types.ShutdownReason;
import com.amazonaws.services.kinesis.model.Record;
/**
* Processes records and checkpoints progress.
*/
public class AmazonKinesisApplicationSampleRecordProcessor implements IRecordProcessor {
private static final Log LOG = LogFactory.getLog(AmazonKinesisApplicationSampleRecordProcessor.class);
private String kinesisShardId;
// Backoff and retry settings
private static final long BACKOFF_TIME_IN_MILLIS = 3000L;
private static final int NUM_RETRIES = 10;
// Checkpoint about once a minute
private static final long CHECKPOINT_INTERVAL_MILLIS = 60000L;
private long nextCheckpointTimeInMillis;
private final CharsetDecoder decoder = Charset.forName("UTF-8").newDecoder();
/**
* {@inheritDoc}
*/
@Override
public void initialize(String shardId) {
LOG.info("Initializing record processor for shard: " + shardId);
this.kinesisShardId = shardId;
}
/**
* {@inheritDoc}
*/
@Override
public void processRecords(List<Record> records, IRecordProcessorCheckpointer checkpointer) {
LOG.info("Processing " + records.size() + " records from " + kinesisShardId);
// Process records and perform all exception handling.
processRecordsWithRetries(records);
// Checkpoint once every checkpoint interval.
if (System.currentTimeMillis() > nextCheckpointTimeInMillis) {
checkpoint(checkpointer);
nextCheckpointTimeInMillis = System.currentTimeMillis() + CHECKPOINT_INTERVAL_MILLIS;
}
}
/**
* Process records performing retries as needed. Skip "poison pill" records.
*
* @param records Data records to be processed.
*/
private void processRecordsWithRetries(List<Record> records) {
for (Record record : records) {
boolean processedSuccessfully = false;
for (int i = 0; i < NUM_RETRIES; i++) {
try {
//
// Logic to process record goes here.
//
processSingleRecord(record);
processedSuccessfully = true;
break;
} catch (Throwable t) {
LOG.warn("Caught throwable while processing record " + record, t);
}
// backoff if we encounter an exception.
try {
Thread.sleep(BACKOFF_TIME_IN_MILLIS);
} catch (InterruptedException e) {
LOG.debug("Interrupted sleep", e);
}
}
if (!processedSuccessfully) {
LOG.error("Couldn't process record " + record + ". Skipping the record.");
}
}
}
/**
* Process a single record.
*
* @param record The record to be processed.
*/
private void processSingleRecord(Record record) {
// TODO Add your own record processing logic here
String data = null;
try {
// For this app, we interpret the payload as UTF-8 chars.
data = decoder.decode(record.getData()).toString();
// Assume this record came from AmazonKinesisSample and log its age.
long recordCreateTime = new Long(data.substring("testData-".length()));
long ageOfRecordInMillis = System.currentTimeMillis() - recordCreateTime;
LOG.info(record.getSequenceNumber() + ", " + record.getPartitionKey() + ", " + data + ", Created "
+ ageOfRecordInMillis + " milliseconds ago.");
} catch (NumberFormatException e) {
LOG.info("Record does not match sample record format. Ignoring record with data; " + data);
} catch (CharacterCodingException e) {
LOG.error("Malformed data: " + data, e);
}
}
/**
* {@inheritDoc}
*/
@Override
public void shutdown(IRecordProcessorCheckpointer checkpointer, ShutdownReason reason) {
LOG.info("Shutting down record processor for shard: " + kinesisShardId);
// Important to checkpoint after reaching end of shard, so we can start processing data from child shards.
if (reason == ShutdownReason.TERMINATE) {
checkpoint(checkpointer);
}
}
/** Checkpoint with retries.
* @param checkpointer
*/
private void checkpoint(IRecordProcessorCheckpointer checkpointer) {
LOG.info("Checkpointing shard " + kinesisShardId);
for (int i = 0; i < NUM_RETRIES; i++) {
try {
checkpointer.checkpoint();
break;
} catch (ShutdownException se) {
// Ignore checkpoint if the processor instance has been shutdown (fail over).
LOG.info("Caught shutdown exception, skipping checkpoint.", se);
break;
} catch (ThrottlingException e) {
// Backoff and re-attempt checkpoint upon transient failures
if (i >= (NUM_RETRIES - 1)) {
LOG.error("Checkpoint failed after " + (i + 1) + "attempts.", e);
break;
} else {
LOG.info("Transient issue when checkpointing - attempt " + (i + 1) + " of "
+ NUM_RETRIES, e);
}
} catch (InvalidStateException e) {
// This indicates an issue with the DynamoDB table (check for table, provisioned IOPS).
LOG.error("Cannot save checkpoint to the DynamoDB table used by the Amazon Kinesis Client Library.", e);
break;
}
try {
Thread.sleep(BACKOFF_TIME_IN_MILLIS);
} catch (InterruptedException e) {
LOG.debug("Interrupted sleep", e);
}
}
}
}