Load testing is a crucial aspect of web and API based application development as it helps business to identify and address performance issues before an application goes live.
While k6 is a popular tool for load testing, it lacks built-in graphing capabilities when running locally.
Instead, it allows you to export test results in multiple formats including
In this article, we'll take a look at how to convert k6 run CSV test results into graphs and then leverage Jmeter to plot. Lets do it !
The first step is to run your k6 tests and export the results in CSV format.
You can do this by running the following command:
k6 run --out csv=path/to/results.csv script.js
This command will run your k6 script and save the results in a CSV file located at the specified path.
Since we'll be using JMeter's graph generator plugin to create graphs, we need to convert the k6 CSV results to a format that JMeter can understand.
To do this, we'll use a Python3 script.
Here's a script that converts k6 CSV results to a JMeter-compatible CSV:
pythonimport csvimport reoutput_rows = k6_file = 'result/k6_demo_output.csv'output_file = 'result/converted.csv'convertible_names = ['.*']def convert_to_jmeter_row(row):timestamp = int(row['timestamp']) * 1000elapsed = int(float(row['metric_value']))label = row['metric_name']responseCode = '200'responseMessage = 'OK'threadName = row['scenario']dataType = 'text'success = 'true'failureMessage = ''bytes = 1sentBytes = 2grpThreads = 1allThreads = 1url = row['metric_name']Latency = elapsedIdleTime = 0Connect = 0return [timestamp,elapsed,label,responseCode,responseMessage,threadName,dataType,success,failureMessage,bytes,sentBytes,grpThreads,allThreads,url,Latency,IdleTime,Connect]def in_row(row_name):for row in convertible_names:if re.match(row, row_name):return Truereturn Falsewith open(k6_file, newline='') as file:reader = csv.DictReader(file, delimiter=',')for row in reader:if in_row(row['metric_name']):output_rows.append(convert_to_jmeter_row(row))with open(output_file, 'w', newline='') as file:writer = csv.writer(file)writer.writerow('timeStamp,elapsed,label,responseCode,responseMessage,threadName,dataType,success,failureMessage,bytes,sentBytes,grpThreads,allThreads,URL,Latency,IdleTime,Connect'.split(','))for row in output_rows:writer.writerow(row)
Save this script to a file, say
convert.py, and update the
convertible_names to include the regular expressions you wish the script to match on. In the example above we're including all (
'.*') which will pull in
additional metadata unrelated to response such as
vus_max. We'd recommend to use this script with custom names that are set using K6 Trends. Otherwise, K6 aggregates everything into http_req_duration.
To run the script:
This script will convert the k6 CSV results to JMeter-compatible CSV and save them in a new file located at the specified path.
Once you have the JMeter-compatible CSV file, you can import it into JMeter and use JMeter's graph generator plugin to create graphs.
Here's how to do it:
And that's it! 🙌🏼
With these simple steps, you can easily convert k6 run CSV test results into graphs using JMeter's graph generator plugin.
Happy performance testing and result analysis!