README.md

Python Module

Build, test, lint, and containerize Python applications with Dagger. Auto-detects pip, uv, or poetry.

Requirements

• Dagger v0.20.3 or later
• Python 3.x (version from .python-version file, defaults to 3)

Functions

Function	Description	Key Parameters
PythonVersion	Extract Python version from .python-version	--
Base	Container with Python and source mounted	--
Install	Run package manager install (pip, uv, or poetry)	--
Lint	Run a Python linter	linter (string, optional, default: ruff), args ([]string, optional)
Test	Run tests	runner (string, optional, default: pytest), args ([]string, optional)
Build	Build wheel/sdist and return output directory	outDir (string, optional, default: dist)
Container	Build production container (distroless)	entrypoint (string, optional, default: python), entrypointArgs ([]string, optional)
DebugContainer	Build Alpine-based debug container	entrypoint, entrypointArgs
Publish	Build and push container to registry	entrypoint, entrypointArgs, imageName ([]string, required), registry, username, password

Package Manager Detection

The module auto-detects the package manager:

Lockfile/Config	Package Manager	Install Command
uv.lock	uv	uv sync --frozen
pyproject.toml with [tool.poetry]	poetry	poetry install
requirements.txt	pip	pip install -r requirements.txt
Otherwise	pip	pip install .

Usage Examples

Extract Python version:

dagger call -m github.com/kdihalas/dagger/python --source . python-version

Run tests:

dagger call -m github.com/kdihalas/dagger/python --source . test

Run tests with arguments:

dagger call -m github.com/kdihalas/dagger/python --source . test --args "-v" --args "--tb=short"

Use a different test runner:

dagger call -m github.com/kdihalas/dagger/python --source . test --runner unittest

Run linter:

dagger call -m github.com/kdihalas/dagger/python --source . lint

Use a different linter:

dagger call -m github.com/kdihalas/dagger/python --source . lint --linter flake8

Build distribution:

dagger call -m github.com/kdihalas/dagger/python --source . build

Build a production container:

dagger call -m github.com/kdihalas/dagger/python --source . container --entrypoint python --entrypoint-args "-m,myapp"

Build a debug container:

dagger call -m github.com/kdihalas/dagger/python --source . debug-container

Publish to a registry:

dagger call -m github.com/kdihalas/dagger/python --source . publish \
  --entrypoint python \
  --entrypoint-args "-m,myapp" \
  --image-name myapp:latest \
  --registry docker.io \
  --username myuser \
  --password env:DOCKER_PASSWORD

GitHub Actions

Use the Python module in GitHub Actions to test, lint, and containerize your Python applications:

name: Build Python App

on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  test-and-build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v6
      - uses: dagger/dagger-for-github@v8.4.1
        with:
          version: "0.20.3"
      - name: Run tests
        run: dagger -m github.com/kdihalas/dagger/python call --source . test
      - name: Run linter
        run: dagger -m github.com/kdihalas/dagger/python call --source . lint
      - name: Build distribution
        run: dagger -m github.com/kdihalas/dagger/python call --source . build --out-dir dist
      - name: Build container
        run: dagger -m python call --source . container \
          --entrypoint github.com/kdihalas/dagger/python \
          --entrypoint-args "-m,myapp"
      - name: Publish container
        run: dagger -m github.com/kdihalas/dagger/python call --source . publish \
          --entrypoint python \
          --entrypoint-args "-m,myapp" \
          --image-name myapp:latest \
          --registry docker.io \
          --username ${{ secrets.DOCKER_USERNAME }} \
          --password ${{ secrets.DOCKER_PASSWORD }}