On Load testing
A short intro about load testing with the remarkable tool that is Gatling.
whois
% IANA WHOIS server
% for more information on IANA, visit http://www.iana.org
% This query returned 1 object
domain: vcz.fr
status: ACTIVE
hold: TIGHT
press: ➡️ TO CONTINUE
What is
Testing?
Probably you now
Oh no, here he goes about tests again 😭
credits: Unsplash
What it is
Ensuring, at different stages, that the service you are building, operates how you intended.
how: behaviors under extreme inputs, feature implementation, project architecture, dependencies, security, interactions between services, performance, error recoverability, etc.
What you get
Less deployment failures, development hell / churn / cost, quality issues, time to market, reputational damage.
Better deployment frequency, healthier teams, project durability / profitability.
The Test Pyramid
credits: Mike Cohn
More expensive
Faster
Other types of tests?!
My code WORKS!!
Yes, but does it work well?
A well-developed application may still be subject to security, performance, architectural, resilience, cost, etc. issues.
You can of course follow logs, metrics, traces and KPIs after the fact but what if you shorten the cycle?
Today, we are interested in
Load Testing
But the other ones are cool too!
What is
Load
Testing?
Behaviors
How each individual will use my service? Different user groups, profiles, personas have different impacts on our systems.
Crowd effects
How a large population of individuals can impact our systems? What happens when they focus on a page and when they disperse? What effect did load on a page have on the others?
The anatomy of a Load Test
The anatomy of a Load Test (bis)
Request
VU
(Virtual User)
Scenario
+ think time
Open model
Inject a given number of VUs per unit of time.
No negative feedback: application will receive load at the same rate even if
down.
Suited for pushing queue-based systems.
Closed model
Maintain a given number of active VU.
Negative feedback: application slows down, VUs complete slower.
Suited for pushing interactive systems.
There are different types of Load Tests!
- Stress tests: reach limits to find bottlenecks
- Benchmarks: evaluate relative performance
- Soak tests: evaluate capacity over long periods of time
- Spike testing: check reactions to sudden load peaks
- Scalability testing: validate horizontal and vertical scaling
- Configuration testing: A/B test configuration changes
Check this out!
Ok, we're done with this
What
about
Gatling?
Founded in 2012 in France 🐓
Open source and Enterprise
Heavy-weight of Load Testing
IDE plugins, protocol-agnostic, recorder, HTML reports, etc.
To get started
Good to know
- Handles the load testing
- You take care of the logic
- I hope you love Scala or Java
- Pretty easy to run and automate
- Do not push too far if local machine
I want to scale my tests!
Synchronize the following commands:
- Start as many injectors as you need;
- Configure your scripts and classes;
- Start in "no report" mode;
- Retrieve all simulation logs;
- Generate the final report.
👋