dockrx 0.1.1

Analyze Dockerfiles. Explain size, caching, and security problems with actionable fixes.

DockRx

Analyze Dockerfiles and explain performance, size, caching, and security problems with actionable fixes.

DockRx is built to answer one question well:

How do I improve this Dockerfile?

Instead of stopping at lint-style warnings, DockRx explains impact, prioritizes quick wins, shows copy-paste fixes, and helps you compare before/after improvements.

Try it now — no install required: dockrx.vercel.app is a live web playground where you can paste a Dockerfile and get an instant health report. The CLI adds fix/compare/badge/format and project-context checks.

Alpha note: image-size and build-time numbers in the report are heuristic estimates, not measured from real builds. dockrx fix / suggest auto-fix a subset of rules; others are recommendations only.

Real Example

$ dockrx analyze examples/test

Overall Health
█████████░░░░░░░░░░░
47 / 100
Needs Attention · Grade: F (Poor)

Quick Wins
1. Switch JDK -> JRE runtime          ↓ ~100-300 MB   2 min
2. Add .dockerignore                  ↑ 20-70%        30 sec
3. Remove debug networking tools      ↓ ~15-80 MB     1 min

Estimated Results
↓ ~247 MB image size
↑ ~45% faster builds
↓ 2 security risks

Why DockRx

• diagnosis-oriented output, not just warnings
• rule explanations via dockrx explain
• non-destructive fix previews via dockrx fix (writes Dockerfile.fixed)
• before/after comparison via dockrx compare
• extensible hybrid rule engine for teams

Install

From source (recommended for alpha)

git clone https://github.com/kiwi-07/docrx.git
cd docrx
uv sync
uv run dockrx --version

Naming note: the GitHub repo is docrx, but the installed CLI and Python package are dockrx. Clone into docrx, run the tool as dockrx.

From PyPI

dockrx is published on PyPI:

pip install dockrx
# or
pipx install dockrx
# or run without installing:
uvx --from dockrx dockrx --version

Commands

dockrx analyze .
dockrx analyze Dockerfile
dockrx analyze . --json
dockrx analyze . --score-only

dockrx explain DRX018

dockrx fix . --dry-run --yes
dockrx fix . --yes
dockrx fix . --limit 5

dockrx compare before/ after/
dockrx compare before/ after/ --json

dockrx badge . --format markdown
dockrx suggest . --yes
dockrx format Dockerfile --check

dockrx --version

Full command reference: docs/commands.md

How DockRx Compares to Hadolint

Capability	DockRx	Hadolint
Dockerfile linting	Yes	Yes
Explain impact (size, cache, hardening)	Yes	Limited
ROI-prioritized output	Yes	No
Suggested fixes in output	Yes	Limited
Rule knowledge base (explain)	Yes	No
Non-destructive fix preview	Yes	No
Before/after comparison	Yes	No
Shell linting inside RUN	Limited	Strong
Mature production ecosystem	Early-stage	Very mature

DockRx is not trying to replace Hadolint. Today the best pairing is:

• Hadolint for deep Dockerfile + shell linting
• DockRx for optimization, prioritization, explainability, fixes, and team-facing UX

DockRx is also not a CVE/vulnerability scanner.

Features

• Hybrid rule engine: built-in YAML rules + Python plugins
• Rich terminal diagnosis with health gauge, quick wins, lost points, estimated results, treatment plan
• dockrx explain rule documentation
• dockrx fix / suggest — non-destructive rewrite to Dockerfile.fixed (subset of rules)
• dockrx compare before/after Dockerfile comparison
• dockrx badge health-grade SVG/markdown badges
• dockrx format Dockerfile formatter (--check / --diff safe; --write overwrites in place)
• JSON output for CI or automation
• Project-local rule and plugin overrides
• Configurable via [tool.dockrx] in pyproject.toml

Built-in Rule Coverage

DockRx ships with built-in YAML rules and Python plugins covering:

• cache ordering for npm, pip, Maven, Gradle, Go, and Cargo
• package manager cache cleanup (apt, apk, pip, npm)
• runtime hardening (USER, secrets in ENV, debug tools in runtime)
• image-size reductions (JDK in runtime, large base images, build tools in final stage)
• best practices (HEALTHCHECK, LABEL, .dockerignore, ADD vs COPY)

Configuration

Optional settings in your project's pyproject.toml:

[tool.dockrx]
log-level = "WARNING"
fail-on-severity = "HIGH"          # analyze exit 1 threshold: HIGH|MEDIUM|LOW|INFO|none
default-fix-limit = 3
health-thresholds = { excellent = 90, good = 75, fair = 60, needs-attention = 40 }

JSON Output

dockrx analyze . --json
dockrx compare before/ after/ --json

Roadmap

Now

• static Dockerfile analysis
• rich terminal UX
• explain / fix / compare / badge / suggest / format
• GitHub Action + local extensibility

Next

• image inspection / layer-size analysis
• richer auto-fix coverage
• CLI helpers to scaffold local rules

Later

• HTML reports
• remote rule packs
• VS Code extension

Full roadmap: docs/roadmap.md

Documentation

• Commands: docs/commands.md
• Web playground & API: dockrx.vercel.app · docs/web-api.md
• Extending DockRx: docs/extending.md
• Architecture and scope: docs/architecture.md
• Roadmap: docs/roadmap.md
• Changelog: CHANGELOG.md
• Contributing: CONTRIBUTING.md

Development

uv sync --group dev
uv run pytest
uv run ruff check src/ tests/
uv run dockrx analyze examples/bad
uv run dockrx analyze examples/good
uv run dockrx compare examples/bad examples/good
uv run dockrx fix examples/test --dry-run --yes

License

Apache-2.0