/**
* Licensed to Cloudera, Inc. under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Cloudera, Inc. 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 com.cloudera.flume.handlers.avro;
import java.io.IOException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.cloudera.flume.conf.Context;
import com.cloudera.flume.conf.FlumeConfiguration;
import com.cloudera.flume.conf.SourceFactory.SourceBuilder;
import com.cloudera.flume.core.Event;
import com.cloudera.flume.core.EventSource;
import com.cloudera.flume.reporter.ReportEvent;
import com.cloudera.util.Clock;
import com.google.common.base.Preconditions;
/**
* This sets up the port that listens for incoming flumeAvroEvent rpc calls
* using Avro. This class pretty much mimics ThriftEventSource.
*/
public class AvroEventSource extends EventSource.Base {
/*
* In this version I am setting the following constants same as for the thrift
* case. Seems like these constants don't really need to depend on the
* underlying implementation, so maybe we can give them more general names
* later.
*/
final static int DEFAULT_QUEUE_SIZE = FlumeConfiguration.get()
.getThriftQueueSize();
final static long MAX_CLOSE_SLEEP = FlumeConfiguration.get()
.getThriftCloseMaxSleep();
static final Logger LOG = LoggerFactory.getLogger(AvroEventSource.class);
public static final String A_QUEUE_CAPACITY = "queueCapacity";
public static final String A_QUEUE_FREE = "queueFree";
public static final String A_ENQUEUED = "enqueued";
public static final String A_DEQUEUED = "dequeued";
// BytesIN in here (unlike the Thrift version) corresponds to the total bytes
// of Event.body shipped.
public static final String A_BYTES_IN = "bytesIn";
final int port;
private FlumeEventAvroServerImpl svr;
final BlockingQueue<Event> q;
final AtomicLong enqueued = new AtomicLong();
final AtomicLong dequeued = new AtomicLong();
final AtomicLong bytesIn = new AtomicLong();
boolean closed = true;
/**
* Create a Avro event source listening on port with a qsize buffer.
*/
public AvroEventSource(int port, int qsize) {
this.port = port;
this.svr = new FlumeEventAvroServerImpl(port);
this.q = new LinkedBlockingQueue<Event>(qsize);
}
/**
* Get reportable data from the Avro event source.
*/
@Override
synchronized public ReportEvent getMetrics() {
ReportEvent rpt = super.getMetrics();
rpt.setLongMetric(A_QUEUE_CAPACITY, q.size());
rpt.setLongMetric(A_QUEUE_FREE, q.remainingCapacity());
rpt.setLongMetric(A_ENQUEUED, enqueued.get());
rpt.setLongMetric(A_DEQUEUED, dequeued.get());
rpt.setLongMetric(A_BYTES_IN, bytesIn.get());
return rpt;
}
/**
* This constructor allows the for an arbitrary blocking queue implementation.
*/
public AvroEventSource(int port, BlockingQueue<Event> q) {
Preconditions.checkNotNull(q);
this.port = port;
this.q = q;
}
public AvroEventSource(int port) {
this(port, DEFAULT_QUEUE_SIZE);
}
/**
* Exposed for testing.
*/
void enqueue(Event e) throws IOException {
try {
q.put(e);
enqueued.getAndIncrement();
bytesIn.getAndAdd(e.getBody().length);
} catch (InterruptedException e1) {
LOG.error("blocked append was interrupted", e1);
throw new IOException(e1);
}
}
/**
* {@inheritDoc}
*/
@Override
synchronized public void open() throws IOException {
this.svr = new FlumeEventAvroServerImpl(port) {
@Override
public void append(AvroFlumeEvent evt) {
// convert AvroEvent evt -> e
AvroEventAdaptor adapt = new AvroEventAdaptor(evt);
try {
enqueue(adapt.toFlumeEvent());
} catch (IOException e1) {
e1.printStackTrace();
}
super.append(evt);
}
};
LOG.info(String.format("Avro listening server on port %d...", port));
this.svr.start();
this.closed = false;
}
/**
* {@inheritDoc}
*/
@Override
synchronized public void close() throws IOException {
long sz = q.size();
LOG.info(String.format("Queue still has %d elements ...", sz));
// Close down the server
this.svr.close();
// drain the queue
// TODO (jon) parameterize queue drain max sleep is one minute
long maxSleep = MAX_CLOSE_SLEEP;
long start = Clock.unixTime();
while (q.peek() != null) {
if (Clock.unixTime() - start > maxSleep) {
if (sz == q.size()) {
// no progress made, timeout and close it.
LOG
.warn("Close timed out due to no progress. Closing despite having "
+ q.size() + " values still enqueued");
return;
}
// there was some progress, go another cycle.
start = Clock.unixTime();
}
try {
Thread.sleep(100);
} catch (InterruptedException e) {
LOG.error("Unexpected interrupt of close " + e.getMessage(), e);
Thread.currentThread().interrupt();
closed = true;
throw new IOException(e);
}
}
closed = true;
}
/**
* {@inheritDoc}
*/
@Override
public Event next() throws IOException {
try {
Event e = null;
// block until an event shows up
while ((e = q.poll(100, TimeUnit.MILLISECONDS)) == null) {
synchronized (this) {
// or bail out if closed
if (closed) {
return null;
}
}
}
// return the event
synchronized (this) {
dequeued.getAndIncrement();
updateEventProcessingStats(e);
return e;
}
} catch (InterruptedException e) {
throw new IOException("Waiting for queue element was interrupted! "
+ e.getMessage(), e);
}
}
public static SourceBuilder builder() {
return new SourceBuilder() {
@Override
public EventSource build(Context ctx, String... argv) {
Preconditions
.checkArgument(argv.length == 1, "usage: avroSource(port)");
int port = Integer.parseInt(argv[0]);
return new AvroEventSource(port);
}
};
}
}