Recently, I needed to reproduce a problem that was only occurring when the storefront was under heavy load. As a developer, I cannot easily generate realistic load in my environment and I don't have access to a live production system, so I used JMeter to help me out. JMeter is a Java application for performing load tests on web applications. In this post, I'll show how to use JMeter to quickly set up a simple performance test against the Elastic Path Commerce storefront.

I wanted to see how long it would take to perform a search in the storefront for Canon products. In this case, I wanted JMeter to fire the following query a few hundred times using one or more threads: http://demo.elasticpath.com:8080/storefront/search.ep?categoryId=&keyWords=canon&submit=search

First, I created a thread group under the test plan tree node. (Right-click the test plan and choose Add->Thread Group.) If you want to simulate more than one user hitting the same search at the same time, you can set the number of threads in the thread group configuration.

Next, I added a loop controller to my thread group. (Right-click the thread group and click Add->Logic Controller->Loop Controller.) Here, I defined how many times the loop will run. In my case, I checked the Infinite checkbox.

Then, I added an HTTP request to the loop controller. (Right-clicking the loop controller and click Add->Sampler->HTTP Request.) I set the Server Name, Server Port, URL Path, chose GET in the dropdown and set three parameters in the request URL.

At this point, I started the test by clicking Run->Start. JMeter starts to execute the HTTP request I defined in the loop controller. Since I set the loop count to Forever, it will continue to execute until I stop it.

Now, it would be a good idea to attach some reports to debug the execution. I tried a few reports and found that the View Results Tree presented all the information I needed. It shows the raw request sent by JMeter and the response data the server is providing. You can examine the server response to make sure the HTTP request you configured is doing what it is expected to do.

To add a View Results Tree report to your test plan, right-click your HTTP request test, and choose Add->Listener->View Results Tree.

You can finally see the results of each call on the report.

You can build more complex tests, with several simultaneous requests over different URLs. For example, you can configure JMeter to first simulate a user logging in to your application (and hold session information), then a few requests to simulate the user navigating through the web application and then repeat this test a few hundred times using as many threads as you want (or your machine can handle).

Using JMeter, I was able to simulate a sufficently heavy load to reproduce the problem I wanted to reproduce and this post should help you do the same thing if you face a similar problem. For more details on JMeter, go to: http://jakarta.apache.org/jmeter/

Hope you enjoy!