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Efficient reliable UDP unicast, UDP multicast, and IPC transport protocol.
/*
* Copyright 2014-2021 Real Logic Limited.
*
* Licensed 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
*
* https://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 io.aeron.samples.cluster.tutorial;
import io.aeron.cluster.client.AeronCluster;
import io.aeron.cluster.client.EgressListener;
import io.aeron.cluster.codecs.EventCode;
import io.aeron.driver.MediaDriver;
import io.aeron.driver.ThreadingMode;
import io.aeron.logbuffer.Header;
import org.agrona.DirectBuffer;
import org.agrona.ExpandableArrayBuffer;
import org.agrona.MutableDirectBuffer;
import org.agrona.concurrent.BackoffIdleStrategy;
import org.agrona.concurrent.IdleStrategy;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;
import static io.aeron.samples.cluster.tutorial.BasicAuctionClusteredService.*;
import static io.aeron.samples.cluster.tutorial.BasicAuctionClusteredServiceNode.calculatePort;
/**
* Client for communicating with {@link BasicAuctionClusteredService}.
*/
// tag::client[]
public class BasicAuctionClusterClient implements EgressListener
// end::client[]
{
private final MutableDirectBuffer actionBidBuffer = new ExpandableArrayBuffer();
private final IdleStrategy idleStrategy = new BackoffIdleStrategy();
private final long customerId;
private final int numOfBids;
private final int bidIntervalMs;
private long correlationId = ThreadLocalRandom.current().nextLong();
private long lastBidSeen = 100;
/**
* Construct a new cluster client for the auction.
*
* @param customerId for the client.
* @param numOfBids to make as a client.
* @param bidIntervalMs between the bids.
*/
public BasicAuctionClusterClient(final long customerId, final int numOfBids, final int bidIntervalMs)
{
this.customerId = customerId;
this.numOfBids = numOfBids;
this.bidIntervalMs = bidIntervalMs;
}
/**
* {@inheritDoc}
*/
// tag::response[]
public void onMessage(
final long clusterSessionId,
final long timestamp,
final DirectBuffer buffer,
final int offset,
final int length,
final Header header)
{
final long correlationId = buffer.getLong(offset + CORRELATION_ID_OFFSET);
final long customerId = buffer.getLong(offset + CUSTOMER_ID_OFFSET);
final long currentPrice = buffer.getLong(offset + PRICE_OFFSET);
final boolean bidSucceed = 0 != buffer.getByte(offset + BID_SUCCEEDED_OFFSET);
lastBidSeen = currentPrice;
printOutput(
"SessionMessage(" + clusterSessionId + ", " + correlationId + "," +
customerId + ", " + currentPrice + ", " + bidSucceed + ")");
}
/**
* {@inheritDoc}
*/
public void onSessionEvent(
final long correlationId,
final long clusterSessionId,
final long leadershipTermId,
final int leaderMemberId,
final EventCode code,
final String detail)
{
printOutput(
"SessionEvent(" + correlationId + ", " + leadershipTermId + ", " +
leaderMemberId + ", " + code + ", " + detail + ")");
}
/**
* {@inheritDoc}
*/
public void onNewLeader(
final long clusterSessionId,
final long leadershipTermId,
final int leaderMemberId,
final String ingressEndpoints)
{
printOutput("NewLeader(" + clusterSessionId + ", " + leadershipTermId + ", " + leaderMemberId + ")");
}
// end::response[]
private void bidInAuction(final AeronCluster aeronCluster)
{
long keepAliveDeadlineMs = 0;
long nextBidDeadlineMs = System.currentTimeMillis() + ThreadLocalRandom.current().nextInt(1000);
int bidsLeftToSend = numOfBids;
while (!Thread.currentThread().isInterrupted())
{
final long currentTimeMs = System.currentTimeMillis();
if (nextBidDeadlineMs <= currentTimeMs && bidsLeftToSend > 0)
{
final long price = lastBidSeen + ThreadLocalRandom.current().nextInt(10);
final long correlationId = sendBid(aeronCluster, price);
nextBidDeadlineMs = currentTimeMs + ThreadLocalRandom.current().nextInt(bidIntervalMs);
keepAliveDeadlineMs = currentTimeMs + 1_000; // <1>
--bidsLeftToSend;
printOutput(
"Sent(" + (correlationId) + ", " + customerId + ", " + price + ") bidsRemaining=" +
bidsLeftToSend);
}
else if (keepAliveDeadlineMs <= currentTimeMs) // <2>
{
if (bidsLeftToSend > 0)
{
aeronCluster.sendKeepAlive();
keepAliveDeadlineMs = currentTimeMs + 1_000; // <3>
}
else
{
break;
}
}
idleStrategy.idle(aeronCluster.pollEgress());
}
}
// tag::publish[]
private long sendBid(final AeronCluster aeronCluster, final long price)
{
final long correlationId = this.correlationId++;
actionBidBuffer.putLong(CORRELATION_ID_OFFSET, correlationId); // <1>
actionBidBuffer.putLong(CUSTOMER_ID_OFFSET, customerId);
actionBidBuffer.putLong(PRICE_OFFSET, price);
idleStrategy.reset();
while (aeronCluster.offer(actionBidBuffer, 0, BID_MESSAGE_LENGTH) < 0) // <2>
{
idleStrategy.idle(aeronCluster.pollEgress()); // <3>
}
return correlationId;
}
// end::publish[]
/**
* Ingress endpoints generated from a list of hostnames.
*
* @param hostnames for the cluster members.
* @return a formatted string of ingress endpoints for connecting to a cluster.
*/
public static String ingressEndpoints(final List hostnames)
{
final StringBuilder sb = new StringBuilder();
for (int i = 0; i < hostnames.size(); i++)
{
sb.append(i).append('=');
sb.append(hostnames.get(i)).append(':').append(
calculatePort(i, BasicAuctionClusteredServiceNode.CLIENT_FACING_PORT_OFFSET));
sb.append(',');
}
sb.setLength(sb.length() - 1);
return sb.toString();
}
private void printOutput(final String message)
{
System.out.println(message);
}
/**
* Main method for launching the process.
*
* @param args passed to the process.
*/
public static void main(final String[] args)
{
final int customerId = Integer.parseInt(System.getProperty("aeron.cluster.tutorial.customerId")); // <1>
final int numOfBids = Integer.parseInt(System.getProperty("aeron.cluster.tutorial.numOfBids")); // <2>
final int bidIntervalMs = Integer.parseInt(System.getProperty("aeron.cluster.tutorial.bidIntervalMs")); // <3>
final String[] hostnames = System.getProperty(
"aeron.cluster.tutorial.hostnames", "localhost,localhost,localhost").split(",");
final String ingressEndpoints = ingressEndpoints(Arrays.asList(hostnames));
final BasicAuctionClusterClient client = new BasicAuctionClusterClient(customerId, numOfBids, bidIntervalMs);
// tag::connect[]
try (
MediaDriver mediaDriver = MediaDriver.launchEmbedded(new MediaDriver.Context() // <1>
.threadingMode(ThreadingMode.SHARED)
.dirDeleteOnStart(true)
.dirDeleteOnShutdown(true));
AeronCluster aeronCluster = AeronCluster.connect(
new AeronCluster.Context()
.egressListener(client) // <2>
.egressChannel("aeron:udp?endpoint=localhost:0") // <3>
.aeronDirectoryName(mediaDriver.aeronDirectoryName())
.ingressChannel("aeron:udp") // <4>
.ingressEndpoints(ingressEndpoints))) // <5>
{
// end::connect[]
client.bidInAuction(aeronCluster);
}
}
}