#python locust

Load Testing dengan Locust

Locust adalah sebuah tools yang dapat digunakan seorang Software QA Engineer untuk melakukan load testing aplikasi berbasis website. Load Testing dilakukan untuk mengetahui seberapa kemampuan system yang digunakan, berapa concurrent user dan berapa request per detik yang mampu dihandel oleh aplikasi tersebut.

Start new Locust swarm

Locust akan optimal jika berjalan di Unix Machine, tetapi untuk…

This blog post just summarizes my understanding of the framework. Refer documentation to see snippets to understand the notes below better.

Main features:

1) EventDriven Non-Blocking:

Locust helps achieve concurrency of higher rates than that can be achieved when using multiple threads or light weight process as in java. As each LWP uses some ram and the concurrency is limited by ram and cpu. The CPU’s IO wait time increases and chokes the load average of the system.

In case of locust its built on gevent which in turn is built using greenlet and is tightly couple libevnt kernel lib (/dev/epoll) that propagates events. This event driven approach enables multiple task to execute in a single thread. Similar to javascript single thread event based loop execution.

Hence a greater concurrency or request can be achieved on smaller configuration of ram and cpu.

gevent over greenlet wraps callback structure of libevent to simpler synchronized constructs that can be used to make programming simple and avoid callback hell.

Note: More info of getevn and greenlet will be in separate blog post

2) RealTime metrics:

Locust also enables realtime view of request and response outcome, throughput etc.. unlike other test framework where post test is when we find reports of the test.

Installation:

Note: Ensure you have libeven installed

pip install locustio

or 

easy_install locustio

Note: using virtualenv is better to work with different lib and version of python

Distributed load testing in locust is achieved by pyzmq (ZeroMQ)

The intercommunication across test running in different boxes is through pyzmq

Distributed mode involves master running just the UI and orchestrating the slaves rather than actually running the test. master takes care of dividing the load and number of users across slaves equally and collects statics from the slaves

Master runs a server on its hosts on port 5997(default can be changed) and the slaves when started are specified the host and port of master to connect to

starting master and slave is as simple as

locust -f <path to locust file> --master

locust -f <path to locust file> --slave master-host=<master host ip>