Load Testing with Locust.io

Transcript

1. LOCUST.IO Load Testing Made Easy James Carr Infrastructure Engineering Director, Zapier
2. TONIGHT ➤ Brief discussion on load testing ➤ Introduction to locust.io ➤ Quickstart Demo + Distributed Demo ➤ In depth details ➤ More Demos! ➤ load testing non-http services ➤ using influxDB + Grafana to graph response times
3. LOAD TESTING Why it matters
4. PROVISIONING ➤ Without load testing, we’re left to make educated guesses ➤ sometimes we can reason about capacity by performing canaries, then applying mathematics ➤ Even so, it’s good to know when the breaking point is of a single service ➤ and be able to scale out accordingly ➤ Being able to scientifically prove limits and responsiveness is very important!
5. STYLES OF TESTING
6. EXISTING TOOLS
7. ANTI-FEATURE ➤GUI to Write Tests ➤Declarative ➤Expensive Scaling
9. SOME UNMET NEEDS ➤ Want to be able to write in the language we primarily develop in (python) ➤ Also wanted to leverage existing client code ➤ Even use auth details from Vault ➤ Want to test non-http services (rabbitmq, memcached, kafka, etc.) ➤ Be able to easily spin up a swarm on EC2 ➤ A dashboard GUI of some kind would be a little nice too
10. ENTER LOCUST.IO
11. “ pip install locustio locust -f locustfile.py
14. CAN USE EXISTING CODEBASE TOO!
15. LOUST.IO ➤ found randomly while looking for a good tool to benchmark mcrouter + N memcached boxes ➤ Tests are written completely in python ➤ Very Flexible… can do anything you can do in python ➤ Can do multi-step tests ➤ e.g. login, set and get this value, etc. ➤ Can run in a distributed environment with many workers
16. DEMO - Quick Start Example - Distributed Example
17. THE LOCUST CLASS ➤ Locust - represents a single user. Locust will spawn one instance of the class for each user being simulated ➤ `task_set` - points to a TaskSet class that defines the behavior of the user ➤ min_wait and max_wait - the minimum and maximum time a user may wait between requests, randomized
18. TASKSET ➤ Methods decorated with @task are executed ➤ providing a number to @task will weight it ➤ task1 will run more often than task2 ➤ on_start - called when a simulated user starts the TaskSet
19. HTTPLOCUST ➤ The HttpLocust contains convenience methods for interacting over http ➤ self.client - HttpSession implementation of requests.Session ➤ The source code of this is a GREAT place to read if you want to extend Locust to support non-http protocols
20. DEMO Load Testing RabbitMQ
21. SOME FURTHER EXPLORATION…
22. WORKING WITH EVENTS ➤ locust.events - fire events on various different things ➤ can be appended to quite easily to add handlers
23. ➤ Obviously there’s a lot of interesting things we can do with event handling ➤ Very crucial if you make your own custom Locust class to define startup / shutdown behaviors ➤ One interesting way to use them: building a custom metric collection mechanism.
24. LOCUST.IO + INFLUXDB + GRAFANA
25. FINAL DEMO
26. CLOSING THOUGHTS ➤ Use docker-swarm + EC2 for quick load test swarming ➤ Some rough edges… more built for hacking versus declaratively defining tests ➤ https://github.com/jamescarr/locust.io-demo ➤ Questions?