Developer’s Guide

Developing VulnScout

Requirements

Docker or Podman (rootless or with your user in the docker group)
Node.js 22 (via NVM) is required to develop the frontend without issues. Installation guide: nvm

nvm install 22
nvm use 22

Project Structure

Directory	Purpose
`src/`	Python/Flask backend (controllers, models, routes, helpers)
`frontend/`	React + TypeScript frontend (Vite, Tailwind CSS)
`tests/`	Backend unit, integration, end-to-end and webapp tests
`frontend/tests/`	Frontend unit tests (Jest + Testing Library)
`src/migrations/`	Alembic database migrations
`.vulnscout/`	Local cache, outputs and example input files

Modify the Backend

The backend is a Flask application located in src/. When running in dev mode the local src/ directory is mounted into the container, so any change is picked up immediately without rebuilding the image.

Start the container in dev mode:

./vulnscout --dev start

Or start with inputs and the web UI in one step:

./vulnscout --dev --serve \
  --add-spdx /path/to/sbom.spdx.json \
  --add-cve-check /path/to/cve-check.json

Flask will run with --debug when DEV_MODE=true is set in the container, enabling auto-reload on Python file changes.

Modify the Frontend

By default, the frontend/ directory is not mounted into the container. To get hot-reload for frontend changes, run VulnScout in dev mode — this starts the backend container and a Vite dev server on the host side:

./vulnscout --dev start

Or combined with a serve command that also loads input files:

./vulnscout --dev --serve \
  --add-spdx /path/to/sbom.spdx.json \
  --add-cve-check /path/to/cve-check.json

The Vite dev server reads VITE_API_URL from frontend/.env (created automatically from the config, default: http://localhost:7275) to proxy API requests to the backend container.

If node_modules are not yet installed, the script will run npm install automatically.

Note: Dev mode requires npm to be available on the host. Use NVM 22 to ensure compatibility.

Testing the Project

We use CQFD to run testing tools in a container.

Quick Setup with CQFD

Step 1: Setup CQFD and Docker/Podman

Install Docker: https://docs.docker.com/engine/install/
Or install Podman: https://podman.io/docs/installation

If using Docker, make sure it runs without requiring sudo. To do so, add your user to the docker group:

sudo groupadd docker
sudo usermod -aG docker $USER

Log out and log back in to apply the changes.

Install CQFD:

git clone https://github.com/savoirfairelinux/cqfd.git
cd cqfd
sudo make install

For more information, visit the CQFD GitHub repository.

Step 2: Initialise CQFD for this Project

Once installed, initialise the container image:

cqfd init

Note: This only needs to be done once, unless the container definition (.cqfd/docker/Dockerfile) is modified.

Step 3: Run Tests with CQFD

To run all tests using CQFD, execute the following command:

cqfd

You can also run the tests separately:

cqfd -b test_backend
cqfd -b test_frontend
cqfd -b test_ci

Running Tests Locally (without CQFD)

Backend

Activate the virtual environment and install dev dependencies first:

python3 -m venv .venv
source .venv/bin/activate
pip install -r requirements/dev.txt

Then run the tests:

# All unit tests
pytest tests/unit_tests/

# All webapp (API) tests
pytest tests/webapp_tests/

# All tests with coverage report in terminal
pytest --cov=src tests/

# All tests with HTML coverage report
pytest --cov-report html --cov=src tests/

# Type checking
mypy --config-file tests/tox.ini

Frontend

cd frontend
npm install
npm run test          # unit tests
npm run coverage      # tests + coverage report
npm run lint          # ESLint
npm run build         # production build check

Setting a Custom Version

The container version is set at build time via the VULNSCOUT_VERSION Docker build argument (defined in the Dockerfile). It is baked into the image as both an environment variable (ENV VULNSCOUT_VERSION) and the OCI label org.opencontainers.image.version.

To build the image with a custom version:

docker build --build-arg VULNSCOUT_VERSION=v1.2.3 -t vulnscout:v1.2.3 .

The version is then available at runtime:

Inside the container: via the VULNSCOUT_VERSION environment variable (used by the Flask /api/version endpoint and entrypoint.sh --version).
From the host: via docker inspect on the image label (used by ./vulnscout --version).

Note: The ci/release_tag.sh script automates version bumps by updating the ARG VULNSCOUT_VERSION line in the Dockerfile along with other version references.

Testing the Docker Image

You can test the Docker image using the provided tests Makefile. To build and test the Docker image, run:

make -C tests docker_build docker_test docker_clean

Optionally set a custom tag:

export BUILD_TAG="my-local-test"
make -C tests docker_build docker_test docker_clean

Code Quality and Linting

Python Backend (Flask)

Task	Command
Linter	`flake8 src`
Type checking	`mypy --config-file tox.ini`
Unit tests	`pytest`
Coverage (terminal)	`pytest --cov=src`
Coverage (HTML)	`pytest --cov-report html --cov=src`

Frontend (React + TypeScript)

Task	Command
Dev server	`npm run dev`
Build	`npm run build`
Unit tests	`npm run test` (uses Jest + Testing Library)
Linter	`npm run lint` (ESLint)
Coverage report	`npm run coverage`

Bash Scripts (`vulnscout` and `entrypoint.sh`)

Task	Command
Linter	`shellcheck vulnscout src/entrypoint.sh`

Note: Running make -C tests test will execute all linters and tests. If pre-commit is installed, flake8 will also run on every commit. With CQFD, use cqfd -b test to run the full suite.

Pre-commit Hook

We use pre-commit to automatically run flake8 before every commit.

To enable it:

pip install pre-commit
pre-commit install

This helps enforce code quality and consistency across all contributions.

Building the Documentation

Full documentation is available in the doc/ directory as a Sphinx project.

Local Build

Install the required Python packages:

pip install sphinx myst-parser sphinx-rtd-theme

Then build the HTML documentation:

make -C doc html

The generated pages are in doc/build/html/. Open doc/build/html/index.html in your browser.

Building with CQFD

If you use CQFD, you can build the documentation inside the CQFD container:

cqfd -b documentation

The generated documentation will be available in doc/build/html/ on the host.

Release Process

VulnScout follows a semantic versioning strategy with development versions between releases.

Version Numbering Strategy

The versioning workflow follows these steps:

Current stable version: v0.9.1 (example - keep for now)
Before creating a release tag: Bump version to v0.10
First PR after release: Bump version to v0.10-dev
Feature PRs: Continue development with -dev suffix
Repeat the cycle