扩展AbstractJavaSamplerClient时应如何管理连接？

Question

I am looking to extend AbstractJavaSamplerClient so that I can fire messages to RabbitMQ. The current setup I have is:

• Have connection and channel objects as instance members
• Create the connection and channel connection in setupTest()
• Send the messages in runTest()
• Clean up the connection in teardownTest()

Code:

package com.the.package.samplers.TheSampler

import ...
...

public final class TheSampler extends AbstractJavaSamplerClient {
    private final ConnectionFactory factory = new ConnectionFactory();
    private Connection connection = null;
    private Channel channel = null;
    ...

    @Override
    public Arguments getDefaultParameters() {
        Arguments parameters = new Arguments();
        ...
        return parameters;

    @Override
    public void setupTest(JavaSamplerContext context) {
        ...
        factory.setHost(host);
        factory.setVirtualHost(vhost);
        factory.setPort(port);
        factory.setUsername(username);
        factory.setPassword(password);

        routingKey = queue;

        try {
            connection = factory.newConnection();
            channel = connection.createChannel();
            channel.exchangeDeclare(exchange, EXCHANGE_TYPE, true);
            channel.queueDeclare(queue, true, false, false, null);
            channel.queueBind(queue, exchange, routingKey);
        }
        catch(IOException e) {
            ...
        }
    }

    @Override
    public SampleResult runTest(JavaSamplerContext context) {
        ...
        channel.basicPublish(exchange, routingKey, null, message.getBytes());
        ...
    }

    @Override
    public void teardownTest(JavaSamplerContext context) {
        try {
            channel.close();
            connection.close();
        }
        catch(IOException e) {
            ...
        }
    }
}

After running the JMeter test with 5 threads for some time, the message rate drops and I start seeing the following exception (repeated indefinitely):

ERROR - jmeter.threads.JMeterThread: Error while processing sampler 'Java Request' : com.rabbitmq.client.AlreadyClosedException: connection is already closed due to connection error; cause: java.net.SocketException: Connection reset
    at com.rabbitmq.client.impl.AMQChannel.ensureIsOpen(AMQChannel.java:190)
    at com.rabbitmq.client.impl.AMQChannel.transmit(AMQChannel.java:291)
    at com.rabbitmq.client.impl.ChannelN.basicPublish(ChannelN.java:647)
    at com.rabbitmq.client.impl.ChannelN.basicPublish(ChannelN.java:630)
    at com.rabbitmq.client.impl.ChannelN.basicPublish(ChannelN.java:621)
    at com.the.package.samplers.TheSampler.runTest(TheSampler.java:102)
    at org.apache.jmeter.protocol.java.sampler.JavaSampler.sample(JavaSampler.java:191)
    at org.apache.jmeter.threads.JMeterThread.process_sampler(JMeterThread.java:434)
    at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:261)
    at java.lang.Thread.run(Unknown Source)

I tried to be a bit more safe by creating and closing the connection and channel objects in runTest() , but that incurred a huge performance hit (fires at a max of 50 messages per second, and previously was in the thousands).

Is there a way to safely create a connection to RabbitMQ when extending AbstractJavaSamplerClient and running with multiple threads?

Answer 1

I don't see any issue in your code from what you show.

Where is JMeter located regarding rabbitmq server ? ie is there a firewall between them ?

You should check this:

• https://www.rabbitmq.com/reliability.html

Detecting Dead TCP Connections with Heartbeats