Load Impact 4.0 Trial Guide
The purpose of this document is to aid you in exploring the primary features available in Load Impact 4.0 as you go through your evaluation. Version 4.0 utilizes k6, an open source load testing tool that is freely available on GitHub. Version 4.0 can be used via the web GUI or from the command line locally, using k6. Both methods allow you to run tests on our cloud infrastructure, for larger load tests, and access our advanced result analysis features - Load Impact Insights. Note: Locally executed tests must triggered from k6 locally.
- URL Test
- Creating a test from Browser Activity (Using the Chrome Recorder)
- Creating a test from Browser Activity (Converting a HAR file)
- Using k6 locally with the Load Impact Cloud
- Downloading k6
- Results analysis
- Next Steps/Automating testing
- How can I get help?
- Additional resources
- How to create a HAR recording
The simplest way to run your first load test is to run a URL test from the Load Impact User Interface.
When you click on Create New Test you’ll see this screen:
Figure 1: Test creation options
Select Test URLs, you will then proceed to this screen:
Figure 2, Test URL input screen
Input the target URL for the site, endpoint or system you want to test.
Upon run/save and run, our URL analyzer visits the URL entered. We analyze the requests being made to completely load the page, including external requests. We create a script from this analysis and use that to run your test. This test is similar to a user visiting that URL, loading all the contents, then closing the tab.
It’s advised that you use the option to filter domains. This allows you to specify which domains you want to be included when generating the script. Generally speaking, you should not test third party resources. For example, trackers, analytic tools, advertising pixels, etc. Depending on your need, you may or may not want to include any Content Delivery Network (CDN) resources.
Domain filtering example: if you are testing test.loadimpact.com, you would use loadimpact.com as the domain filter.
Enter your URLs and test parameters then click the SAVE AND RUN button to start your test.
Next, take a look at your test results:
Figure 3, The performance status section provides a high level overview of the performance of your test. You should consider the following when analyzing your results.
- This test ramps to 50 Virtual Users over 1 minute, stays at 50 Virtual Users for 1 minute, ramps down to 0 Virtual Users over 1 minute.
- If Thresholds were configured, the number of passed
Thresholds / Total Thresholds
- Failed Thresholds return non zero exit codes
- If Checks were configured, the number of passing
Checks / Total Checks
- Checks will not fail a test, nor can they halt execution
- Checks are often used with a Threshold and Custom Metrics
- The number of URLs with a status code
<400 / Total requests
Some Ideal performance result correlations
- Flat response times with rising Virtual Users
- Increasing throughput/request rate with rising Virtual Users
- Low number of errors/error rate not increasing with rising Virtual users
Additional resources can be found in the Results Analysis section at the bottom of this page.
Creating a test from Browser Activity (Using the Chrome Recorder)
When running performance tests, you should make your test cases as realistic as possible. An easy way to do this is to record a browser session. Use the Load Impact k6 Test Script Recorder, available in the Chrome Web Store.
Click on Create New Test and select Browser recording, as shown in Figure 1 above.
Follow the steps as shown in the Load Impact UI to download the chrome extension, start a recording, stop recording, save the test script, and run the test. Then, check your test results.
Creating a test from Browser Activity (Converting a HAR file)
A second way to create realistic tests is to capture activity in your browser and save it as a HAR file. Here is a list of tools that can output HAR files from another document in this knowledge base.
Also note: k6 has a built-in HAR converter that will read HAR files and convert them to k6 test scripts that can then be executed. Refer to this document on converting HAR files locally.
Click on Create New Test and select HAR file upload, as shown in Figure 1 above.
Figure 4, Browser recording input
The HAR file upload allows you to take a recorded browser session, where you emulated real user behavior, and convert that into a k6 script. The requests made in this session will be identical to the ones you made - so if you logged into a system, that will also be attempted. If your system uses any tokens to prevent CSRF attacks, it’s likely that you will see some 400 level responses (since the token has since expired).
Similar to the URL analyzer, you can also filter domains. We advise you to take the same care as mentioned above to limit the test to domains you are able to and want to test.
Simply upload your HAR file, set your test parameters and then click SAVE AND RUN.
Check your test results, as before.
Click on Create New Test and select Scripting as shown on the right side of Figure 1 above. You will see that the in-app script editor is pre-populated with a sample test script. You can edit this script to meet your needs.
Figure 5, In app scripting
Using k6 locally with the Load Impact Cloud
To realize the full value out of Load Impact 4.0, download and install k6 on your local machine. This enables you to run tests that are local behind your firewall, local with result streaming into our cloud service, or on the Load Impact cloud service with results in the cloud all by using the command line.
By working locally, you can use your favorite IDE to write your scripts, create custom modules or libraries to share with your team, and utilize any version control you already have in place. This knowledge base contains sample scripts and code snippets to help you get started.
Aside from where the load generates from and the results output, the script itself remains unchanged between execution modes. This allows you to shift testing left to be available in the development cycle.
k6 is available directly from our GitHub repository. You may also utilize the following install methods:
$ sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 379CE192D401AB61 $ echo "deb https://dl.bintray.com/loadimpact/deb stable main" | sudo tee -a /etc/apt/sources.list $ sudo apt-get update $ sudo apt-get install k6
$ wget https://bintray.com/loadimpact/rpm/rpm -O bintray-loadimpact-rpm.repo $ sudo mv bintray-loadimpact-rpm.repo /etc/yum.repos.d/ $ sudo yum install k6
brew tap loadimpact/k6 brew install k6
Refer to installation options in the k6 docs for additional information
Utilizing k6 locally to trigger tests
Once you’ve installed k6, try these commands to try the different execution modes:
Local Execution with local output
This mode is useful for validations and smoke tests. Load generated from your local machine with output to stdout
Local Execution with cloud streaming output
This mode is useful for testing behind the firewall. Cloud output enables you to analyze your results within Load Impact’s cloud platform. In stdout, you are given a link to the test result to watch in real-time.
Cloud Execution triggered from local command line
This mode allows you to scale to a large number of Virtual Users on demand, utilizing Load Impact’s cloud infrastructure. Your script and it’s dependencies (if applicable) are uploading to our cloud service and then executed. In stdout, you are given a link to the test result to watch in real-time.
Refer to the following resources for more information on result analysis:
Next Steps/Automating testing
As a best practice, building automation into your development cycle for testing provides a multitude of benefits, such as:
- Deploying higher quality code, faster
- Improving efficiencies
- Detecting performance issues, before they become problems in production
Load Impact 4.0 and k6 are designed to fit nicely into automation pipelines or custom processes you’ve already created. The most popular CI tools, such as Circle CI, GitLab, Jenkins, Team City, etc. support making command line calls. This allows k6 to fit nicely into these workflows and build processes. Enabling you to run tests as part of the build process, and halt those builds, should a failing result be returned.
The frequency in which you run tests varies from organization to organization. Our best practice recommendation is to run tests with your nightly builds.
How can I get help?
The Load Impact Support and Client Success teams are here to help should you have questions. You can utilize the icon in the lower right corner of this page to start a chat or email us at support [at] loadimpact.com.