Load testing using LOCUST

Locust is an open-source load-testing tool. Load testing is a type of software testing that is conducted to check the tolerance/behavior of the system under a specific expected load. The target of locust is load-testing websites and checking the number of concurrent users a system can handle. During a locust test, a swarm of locusts will attack the target i.e website. The behavior of each locust is configurable and the swarming process is monitored from a web UI in real time. 

Specialty of locust:

• Test scenarios can be written in Python
• Distributed and scalable
• Web-based UI
• Any system can be tested using this tool

Installation: Locust can be installed with pip.

pip install locust

Once the locust is successfully installed, a locust command should be available in your shell. To see more available options:

locust --help

Getting started:

Python3

from locust import HttpUser, TaskSet, task
from locust import ResponseError
import json


class UserBehavior(TaskSet):

    def __init__(self, parent):
        super(UserBehavior, self).__init__(parent)
        self.token = "
        "
        self.headers = {}

    def on_start(self):
        # The on_start method is called
        # when a simulated user starts
        # executing that TaskSet class
        self.token = self.login()
        self.headers = {'Authorization': 'Bearer {}'.format(self.token)}
        self.login()

    def login(self):
        # admin login  and retrieving it's access token
        response = self.client.post( & quot
                                    / login/"
                                    ,
                                    data={'username': 'admin',
                                           'password': 'ZYT5nsg3565!'})

        return json.loads(response._content)['access']


class WebsiteUser(HttpUser):
    # The task_set attribute should point
    # to a TaskSet class which defines
    # the behaviour of the user
    task_set = UserBehavior
    min_wait = 5000
    max_wait = 9000

Start locust: To run the above code, create a Python file named locustfile.py, and open the terminal in the directory of the above created file. Then write the following command in the terminal.

locust

Note: By default locust searches for locustfile.py. After the successful execution of the above command, you should open a browser and hit http://127.0.0.1:8089 The Locust UI will appear like below: