Introduction to k6.io
How to use k6 for performance testing
agenda
but first..
why performance testing?
We use technology on a daily basis and have been accustomed to instant gratification.
“While customers will forgive and forget the odd bug, crash, or period of site maintenance, they will not tolerate a site that doesn't move at the speed they’ve become accustomed to.”
- Dr. John Bates, CEO, Eggplant from Slow Websites Are Silent Killers for Businesses
Performance Testing
Front End/Client Side
Back End/Server Side
types of performance test
- Load testing
- Soak testing
- Stress testing
What is k6?
k6 is a developer-centric, free and open-source load testing tool built for making performance testing a productive and enjoyable experience - k6 docs
k6 services
k6 open source
k6 cloud
Why was k6 created?
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Tests written in JavaScript
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Flexible
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Test scripting (load testing as code)
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Test recording
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Integrates well with CI/CD pipelines
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Test visualisation with New Relic, Grafana and others!
k6
import http from 'k6/http';
import { sleep } from 'k6';
export default function () {
http.get('https://test.k6.io');
sleep(1);
}
-
Virtual Users (VUs)
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Metrics
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Checks
-
Thresholds
k6 key concepts
virtual users
export const options = {
vus: 10,
duration: '1h',
};
export const options = {
stages: [
{ duration: '1m', target: 10 },
{ duration: '1m', target: 20 },
{ duration: '1m', target: 0 },
]
};
export default function () {
http.get('http://test.k6.io/');
}
metrics
running (00m03.8s), 0/1 VUs, 1 complete and 0 interrupted iterations
default ✓ [======================================] 1 VUs 00m03.8s/10m0s 1/1 iters, 1 per VU
data_received..................: 22 kB 5.7 kB/s
data_sent......................: 742 B 198 B/s
http_req_blocked...............: avg=1.05s min=1.05s med=1.05s max=1.05s p(90)=1.05s p(95)=1.05s
http_req_connecting............: avg=334.26ms min=334.26ms med=334.26ms max=334.26ms p(90)=334.26ms p(95)=334.26ms
http_req_duration..............: avg=2.7s min=2.7s med=2.7s max=2.7s p(90)=2.7s p(95)=2.7s
{ expected_response:true }...: avg=2.7s min=2.7s med=2.7s max=2.7s p(90)=2.7s p(95)=2.7s
http_req_failed................: 0.00% ✓ 0 ✗ 1
http_req_receiving.............: avg=112.41µs min=112.41µs med=112.41µs max=112.41µs p(90)=112.41µs p(95)=112.41µs
http_req_sending...............: avg=294.48µs min=294.48µs med=294.48µs max=294.48µs p(90)=294.48µs p(95)=294.48µs
http_req_tls_handshaking.......: avg=700.6ms min=700.6ms med=700.6ms max=700.6ms p(90)=700.6ms p(95)=700.6ms
http_req_waiting...............: avg=2.7s min=2.7s med=2.7s max=2.7s p(90)=2.7s p(95)=2.7s
http_reqs......................: 1 0.266167/s
iteration_duration.............: avg=3.75s min=3.75s med=3.75s max=3.75s p(90)=3.75s p(95)=3.75s
iterations.....................: 1 0.266167/s
vus............................: 1 min=1 max=1
vus_max........................: 1 min=1 max=1checks
import { check } from 'k6';
import http from 'k6/http';
export default function () {
const res = http.get('http://test.k6.io/');
check(res, {
'is status 200': (r) => r.status === 200,
});
}
k6 run script.js
...
✓ is status 200
...
checks.........................: 100.00% ✓ 1 ✗ 0
data_received..................: 11 kB 12 kB/s
thresholds
import http from 'k6/http';
export const options = {
thresholds: {
http_req_failed: ['rate<0.01'], // http errors should be less than 1%
http_req_duration: ['p(95)<200'], // 95% of requests should be below 200ms
},
};
export default function () {
http.get('https://test-api.k6.io/public/crocodiles/1/');
}
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Tests written in JavaScript
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Load generation distribution not included in the open source version
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Node JS libraries not compatible with k6
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TypeScript support requires a lot of boilerplate so might not be ideal if you want something quick
limitations
demonstration
questions?
Introduction to k6.io
How to use k6 for load testing