perf-lint

Overview

Catch performance test quality issues before they reach production. perf-lint statically analyses your JMeter .jmx, k6 .js/.ts, and Gatling .scala/.kt scripts and reports violations: missing think times, hardcoded values, absent assertions, unrealistic ramp patterns, and more.

Install it in seconds, run it locally or in CI, and get an instant quality score.

pip install perf-lint-tool
perf-lint check tests/

Every file gets a quality score (0–100, grade A–F) based on its violations. The free CLI shows 18 essential rules. Connect to your dashboard to unlock all 53.

Quick Start

# Install
pip install perf-lint-tool

# Analyse a file or directory
perf-lint check test.jmx
perf-lint check tests/ --severity warning

# Auto-fix safe violations in place
perf-lint check test.jmx --fix

# Preview fixes without applying them
perf-lint check test.jmx --fix-dry-run

# Output JSON or SARIF for CI tooling
perf-lint check tests/ --format json
perf-lint check tests/ --format sarif --output results.sarif

What It Detects

53 rules spanning three frameworks — every rule has a clear message, a suggestion, and a fix example.

Framework	Rules	Auto-fixable
Apache JMeter	25	15
k6	15	7
Gatling	13	3
Total	53	25

Example violations detected:

• Missing HTTP Cache Manager / Cookie Manager
• Zero or unrealistic think time (BeanShell timers, constant-only timers)
• Hardcoded hostnames, ports, and auth tokens
• Missing assertions and response checks
• Ramp-up periods too short for the target load
• Missing correlation / dynamic variable extraction
• No thresholds or graceful stop in k6
• At-once user injection in Gatling

Tier Breakdown

perf-lint runs all 53 rules locally — your scripts never leave your machine. The free CLI shows the 18 most actionable hygiene rules. Connect an API key to see the full picture in your dashboard.

GitHub Action

Add perf-lint to any workflow in under a minute:

- uses: markslilley/perf-lint-action@v1
  with:
    paths: tests/
    severity: warning
    upload_sarif: 'true'        # Surface violations in GitHub Code Scanning
    api_key: ${{ secrets.PERF_LINT_API_KEY }}

Outputs: violations, score, grade — use them in subsequent steps or in PR status checks.

Available on the GitHub Marketplace.

CI/CD Integration

GitHub Actions

name: perf-lint
on: [push, pull_request]

jobs:
  lint:
    runs-on: ubuntu-latest
    permissions:
      security-events: write   # Required for SARIF upload
    steps:
      - uses: actions/checkout@v4
      - uses: markslilley/perf-lint-action@v1
        with:
          paths: tests/
          upload_sarif: 'true'
          api_key: ${{ secrets.PERF_LINT_API_KEY }}

Any CI (pip + CLI)

pip install perf-lint-tool
perf-lint check tests/ --severity warning --format json --output results.json

Configuration

Create a .perf-lint.yml at the root of your repository to customise behaviour:

# .perf-lint.yml
severity: warning        # Minimum severity to report

rules:
  JMX003:
    severity: error      # Escalate a rule
  JMX013:
    enabled: false       # Silence a rule

ignore_paths:
  - "tests/fixtures/**"
  - "**/*.bak.jmx"

Generate a starter config:

perf-lint init

How the Score Works

Each file is scored 0–100 based on its violations:

score = max(0, 100 − (errors × 15) − (warnings × 5) − (infos × 1))

Score	Grade
90–100	A
75–89	B
60–74	C
40–59	D
0–39	F

The overall score is the unweighted average across all analysed files.

Why perf-lint?

Problem	Without perf-lint	With perf-lint
Missing think time	Discovered during test run (too late)	Caught at commit time
Hardcoded hostnames	Breaks in CI, prod environments silently	ERROR flagged immediately
No assertions	Tests pass even when application fails	Detected before merge
BeanShell timers	Performance bottleneck in production run	Highlighted with fix suggestion
Unrealistic ramp-up	Results invalidated — wasted test run	Caught before execution

Open Source

perf-lint is open source under the MIT licence.

• GitHub: markslilley/perf-lint
• PyPI: perf-lint-tool
• GitHub Action: markslilley/perf-lint-action
• Dashboard: perflint.martkos-it.co.uk

Contributions, bug reports, and rule requests welcome.