Stress Testing with stress_test.py

stress_test.py is an advanced and dependency-free HTTP load and stress testing tool written in Python, designed specifically for developers and system administrators who need to assess the performance limits of their websites, APIs, or servers. By using the Python standard library (compatible with Python 3.8+), this tool enables users to conduct thorough capacity tests without the need for additional installations. It is compatible with macOS, Linux, and Chromebook environments.

Key Features

• Dependency-Free: Operates solely with Python's standard library.
• Configurable Traffic Mapping: Users can define various traffic stages to simulate how the server handles increasing loads, revealing performance breakpoints.
• Comprehensive Reporting: Outputs include latency percentiles, throughput rates, and error metrics across four formats: text, JSON, CSV, and a standalone HTML report.

How It Works

The tool executes stress tests by sending HTTP requests to any server specified in the user-defined allowlist.txt. The following operational modes are available:

• Staged Testing: Execute multiple stages of varying traffic loads.
• Open-Loop Rate Testing: Send requests at a fixed rate, simulating real user scenarios.
• Capacity Search: Automatically ramp up the request rates until performance objectives are breached, effectively locating the server’s maximum operational capacity.

Core Concepts

• Stages: Each test can consist of several configurable stages to observe how performance degrades as load increases. For instance, you can establish stages for warming up the server, ramping up the request load, sustaining that load, and then cooling down.
• Latency Measurement: The tool accurately reports latency through metric percentiles (p50, p95, p99), enabling users to focus on performance aspects that matter most.

Getting Started

Performing a basic stress test is straightforward. Below is an example sequence to get started:

1. Set Up Allowlist: Add your server or API to allowlist.txt.

   echo "example.com" >> allowlist.txt
   

2. Run a Simple Test: Execute a basic test with the following command:

   python3 stress_test.py https://example.com/ --i-own-this
   

3. Advanced Configuration: Use multiple processes and configure your test profile to simulate heavier load:

   python3 stress_test.py https://example.com/ --i-own-this --profile heavy --processes 8 --pipeline 16 --html report.html
   

Important Usage Guidelines

Please ensure that testing is conducted only on servers owned or permitted to be tested. It is crucial to respect the legality and ethics of load testing — unauthorized testing can lead to severe legal consequences.

Use Cases

Primarily intended for:

• Developers seeking to optimize their applications for performance under load.
• System Administrators who need to validate the robustness of infrastructure before high-traffic events.
• Quality Assurance Engineers aiming for performance benchmarks during CI/CD pipelines.

For more detailed options and advanced setups, consult the full option reference and built-in profiles outlined in the README.