Part 2: Industrialize and secure an advanced Python CI/CD pipeline
Published on 18 July 2025
- Introduction
- CI/CD Pipeline Architecture
- Project Structure
- Package Configuration with pyproject.toml
- CI/CD Workflow - Tests and Quality
- Release and Deployment Workflow
- Architecture Diagrams
- Objects and Models of the Pipeline
- Secrets Configuration
- Local Development Scripts
- Best Practices and Recommendations
- Monitoring and Observability
- Conclusion
- Additional Resources
Introduction
In the first part of this series, we built a simple but effective CI/CD pipeline to automate testing and publishing a Python package to PyPI.
It is now time to professionalize this pipeline. In this second part, we are going to:
-
Migrate to the modern pyproject.toml standard,
-
Add quality and safety tools (Black, Mypy, Bandit, Safety)
-
Set up multi-version tests,
-
Integrate a gradual deployment via Test PyPI,
-
Automate versioning and improve pipeline monitoring.
Get ready to move from a functional pipeline to a professional CI/CD infrastructure.
Deploying a Python application to PyPI requires a robust CI/CD pipeline that automates testing, building, and publishing packages. This article details the setup of a complete pipeline using GitHub Actions for a Python CLI application, based on the best practices of the modern Python ecosystem.
CI/CD Pipeline Architecture
The pipeline we are going to build follows a multi-step approach:
@startuml
!theme plain
title Python CI/CD pipeline to PyPI
skinparam backgroundColor #f8f9fa
skinparam componentStyle rectangle
rectangle "Developer" as dev
rectangle "GitHub Repository" as repo {
rectangle ".github/workflows/" as workflows
rectangle "tests/" as tests
rectangle "setup.py / pyproject.toml" as setup
rectangle "requirements.txt" as req
}
rectangle "GitHub Actions" as actions {
rectangle "Test Runner" as test_runner
rectangle "Build" as build
rectangle "Security Scan" as security
rectangle "(No output, as there is no French text provided to translate.)" as quality
}
rectangle "PyPI" as pypi {
rectangle "Test PyPI" as test_pypi
rectangle "Production PyPI" as prod_pypi
}
rectangle "Users" as users
dev --> repo : push/PR
repo --> actions : trigger workflow
actions --> test_runner : run tests
actions --> security : security checks
actions --> quality : code quality
actions --> build : build package
build --> test_pypi : deploy (pre-release)
build --> prod_pypi : deploy (release)
prod_pypi --> users : install package
@enduml
Project Structure
A Python CLI application ready for distribution must adhere to a standardized structure:
playlist-downloader/
├── .github/
│ └── workflows/
│ ├── ci.yml
│ ├── release.yml
│ └── security.yml
├── src/
│ └── playlist_downloader/
│ ├── __init__.py
│ ├── cli.py
│ ├── core/
│ └── adapters/
├── tests/
│ ├── unit/
│ ├── integration/
│ └── conftest.py
├── docs/
├── pyproject.toml
├── requirements.txt
├── requirements-dev.txt
├── MANIFEST.in
├── README.md
├── LICENSE
└── CHANGELOG.md
Package Configuration with pyproject.toml
The file`pyproject.toml`is the modern standard for configuring Python packages:
[build-system]
requires = ["setuptools>=45", "wheel", "setuptools_scm>=6.2"]
build-backend = "setuptools.build_meta"
[project]
name = "playlist-downloader"
authors = [
{name = "Christophe Hérolivier", email = "[email protected]"},
]
description = "CLI tool for YouTube playlist management"
readme = "README.md"
requires-python = ">=3.8"
keywords = ["youtube", "playlist", "cli", "downloader"]
license = {text = "MIT"}
classifiers = [
"Development Status :: 4 - Beta",
"Environment :: Console",
"Intended Audience :: End Users/Desktop",
"License :: OSI Approved :: MIT License",
"Operating System :: OS Independent",
"Programming Language :: Python :: 3",
"Programming Language :: Python :: 3.8",
"Programming Language :: Python :: 3.9",
"Programming Language :: Python :: 3.10",
"Programming Language :: Python :: 3.11",
"Topic :: Multimedia :: Sound/Audio",
"Topic :: Utilities",
]
dependencies = [
"typer>=0.9.0",
"yt-dlp>=2023.7.6",
"google-api-python-client>=2.0.0",
"google-auth-oauthlib>=1.0.0",
"pyyaml>=6.0",
"rich>=13.0.0",
]
dynamic = ["version"]
[project.optional-dependencies]
dev = [
"pytest>=7.0.0",
"pytest-cov>=4.0.0",
"pytest-mock>=3.10.0",
"black>=23.0.0",
"flake8>=6.0.0",
"mypy>=1.0.0",
"pre-commit>=3.0.0",
"tox>=4.0.0",
]
test = [
"pytest>=7.0.0",
"pytest-cov>=4.0.0",
"pytest-mock>=3.10.0",
]
[project.urls]
Homepage = "https://github.com/cheroliv/playlist-downloader"
Documentation = "https://github.com/cheroliv/playlist-downloader#readme"
Repository = "https://github.com/cheroliv/playlist-downloader.git"
"Bug Tracker" = "https://github.com/cheroliv/playlist-downloader/issues"
[project.scripts]
playlist-downloader = "playlist_downloader.cli:main"
[tool.setuptools_scm]
write_to = "src/playlist_downloader/_version.py"
[tool.setuptools.packages.find]
where = ["src"]
[tool.pytest.ini_options]
testpaths = ["tests"]
python_files = ["test_*.py"]
python_classes = ["Test*"]
python_functions = ["test_*"]
addopts = [
"--cov=src/playlist_downloader",
"--cov-report=html",
"--cov-report=term-missing",
"--cov-fail-under=85",
]
[tool.black]
line-length = 88
target-version = ['py38']
include = '\.pyi?$'
extend-exclude = '''
/(
\.eggs
| \.git
| \.hg
| \.mypy_cache
| \.tox
| \.venv
| _build
| buck-out
| build
| dist
)/
'''
[tool.mypy]
python_version = "3.8"
warn_return_any = true
warn_unused_configs = true
disallow_untyped_defs = true
disallow_incomplete_defs = true
check_untyped_defs = true
disallow_untyped_decorators = true
no_implicit_optional = true
warn_redundant_casts = true
warn_unused_ignores = true
warn_no_return = true
warn_unreachable = true
strict_equality = true
[[tool.mypy.overrides]]
module = [
"yt_dlp.*",
"googleapiclient.*",
"google_auth_oauthlib.*",
]
ignore_missing_imports = true
CI/CD Workflow - Tests and Quality
The main workflow (ci.yml) runs the tests on multiple versions of Python :
name: CI
on:
push:
branches: [ main, develop ]
pull_request:
branches: [ main ]
jobs:
test:
runs-on: ubuntu-latest
strategy:
matrix:
python-version: ["3.8", "3.9", "3.10", "3.11"]
steps:
- uses: actions/checkout@v4
with:
fetch-depth: 0
- name: Set up Python ${{ matrix.python-version }}
uses: actions/setup-python@v4
with:
python-version: ${{ matrix.python-version }}
- name: Cache dependencies
uses: actions/cache@v3
with:
path: |
~/.cache/pip
~/.cache/pre-commit
key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements*.txt') }}
restore-keys: |
${{ runner.os }}-pip-
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install -e ".[dev]"
- name: Lint with flake8
run: |
flake8 src tests --count --select=E9,F63,F7,F82 --show-source --statistics
flake8 src tests --count --exit-zero --max-complexity=10 --max-line-length=88 --statistics
- name: Check code formatting with Black
run: black --check src tests
- name: Type checking with mypy
run: mypy src
- name: Run tests with pytest
run: |
pytest tests/ -v --cov=src/playlist_downloader \
--cov-report=xml --cov-report=term-missing
- name: Upload coverage to Codecov
uses: codecov/codecov-action@v3
if: matrix.python-version == '3.11'
with:
file: ./coverage.xml
flags: unittests
name: codecov-umbrella
security:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: "3.11"
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install bandit[toml] safety
- name: Run security checks with bandit
run: bandit -r src/ -f json -o bandit-report.json
- name: Check dependencies with safety
run: safety check --json --output safety-report.json
- name: Upload security reports
uses: actions/upload-artifact@v3
if: always()
with:
name: security-reports
path: |
bandit-report.json
safety-report.json
build:
needs: [test, security]
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
with:
fetch-depth: 0
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: "3.11"
- name: Install build dependencies
run: |
python -m pip install --upgrade pip
pip install build twine
- name: Build package
run: python -m build
- name: Check package with twine
run: twine check dist/*
- name: Upload build artifacts
uses: actions/upload-artifact@v3
with:
name: dist
path: dist/
Release and Deployment Workflow
The release workflow (release.yml) manages the automatic publishing to PyPI :
name: Release
on:
push:
tags:
- 'v*.*.*'
workflow_dispatch:
inputs:
environment:
description: 'Deployment environment'
required: true
default: 'test'
type: choice
options:
- test
- production
env:
PYTHON_VERSION: "3.11"
jobs:
release:
runs-on: ubuntu-latest
environment:
name: ${{ github.event.inputs.environment || (startsWith(github.ref, 'refs/tags/') && 'production' || 'test') }}
steps:
- uses: actions/checkout@v4
with:
fetch-depth: 0
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: ${{ env.PYTHON_VERSION }}
- name: Install dependencies
run: |
python -m pip install --upgrade pip
pip install build twine
- name: Build package
run: python -m build
- name: Check package
run: twine check dist/*
- name: Publish to Test PyPI
if: github.event.inputs.environment == 'test' || (startsWith(github.ref, 'refs/tags/') && contains(github.ref, 'rc'))
env:
TWINE_USERNAME: __token__
TWINE_PASSWORD: ${{ secrets.TEST_PYPI_API_TOKEN }}
run: |
twine upload --repository testpypi dist/*
- name: Publish to PyPI
if: github.event.inputs.environment == 'production' || (startsWith(github.ref, 'refs/tags/') && !contains(github.ref, 'rc'))
env:
TWINE_USERNAME: __token__
TWINE_PASSWORD: ${{ secrets.PYPI_API_TOKEN }}
run: |
twine upload dist/*
- name: Create GitHub Release
if: startsWith(github.ref, 'refs/tags/')
uses: actions/create-release@v1
env:
GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
with:
tag_name: ${{ github.ref }}
release_name: Release ${{ github.ref }}
draft: false
prerelease: ${{ contains(github.ref, 'rc') }}
post-release:
needs: release
runs-on: ubuntu-latest
if: startsWith(github.ref, 'refs/tags/')
steps:
- uses: actions/checkout@v4
- name: Set up Python
uses: actions/setup-python@v4
with:
python-version: ${{ env.PYTHON_VERSION }}
- name: Test installation from PyPI
run: |
sleep 60 # Attendre la propagation sur PyPI
pip install playlist-downloader
playlist-downloader --version
- name: Update documentation
run: |
# Script pour mettre à jour la documentation
echo "Documentation updated for version ${GITHUB_REF#refs/tags/}"
Architecture Diagrams
Sequence Diagram - Release Process
@startuml
!theme plain
title Release sequence to PyPI
actor Developer as dev
participant "GitHub" as gh
participant "GitHub Actions" as ga
participant "Test PyPI" as tpypi
participant "PyPI" as pypi
participant "Users" as users
dev -> gh : git push --tags v1.2.3
gh -> ga : trigger release workflow
ga -> ga : checkout code
ga -> ga : setup Python environment
ga -> ga : install dependencies
ga -> ga : run tests
ga -> ga : build package (wheel + sdist)
ga -> ga : check package with twine
alt Pre-release (rc tag)
ga -> tpypi : upload to Test PyPI
tpypi -> ga : confirm upload
else Stable release
ga -> pypi : upload to PyPI
pypi -> ga : confirm upload
end
ga -> gh : create GitHub release
ga -> ga : test installation from PyPI
users -> pypi : pip install playlist-downloader
pypi -> users : download package
@enduml
State Diagram - Package Life Cycle
@startuml
!theme plain
title States of the Python Package
[*] --> Development
Development --> Testing : commit/PR
Testing --> Development : tests fail
Testing --> Built : tests pass
Built --> TestPyPI : pre-release tag
Built --> PyPI : stable tag
TestPyPI --> PyPI : validation OK
PyPI --> Published
Published --> [*]
state Development {
[*] --> Coding
Coding --> LocalTesting
LocalTesting --> Coding : fix issues
LocalTesting --> ReadyForCI : all tests pass
}
state Testing {
[*] --> CITests
CITests --> SecurityScan
SecurityScan --> QualityCheck
QualityCheck --> BuildValidation
}
@enduml
Deployment Diagram - CI/CD Infrastructure
@startuml
!theme plain
title Deployment Infrastructure
node "GitHub" {
component "Repository" as repo
component "Actions Runner" as runner
component "Secrets Store" as secrets
}
node "PyPI Infrastructure" {
component "PyPI" as pypi
component "Test PyPI" as testpypi
database "Package Index" as index
}
node "Developer Machine" {
component "Git Client" as git
component "Python Environment" as python
component "IDE" as ide
}
node "User Environment" {
component "pip" as pip_client
component "Python Runtime" as py_runtime
}
git --> repo : push code/tags
repo --> runner : trigger workflows
runner --> secrets : read API tokens
runner --> testpypi : upload pre-release
runner --> pypi : upload release
pypi --> index : store package
pip_client --> pypi : download package
py_runtime <-- pip_client : install package
@enduml
Objects and Models of the Pipeline
Class Diagram - CI/CD Models
@startuml
!theme plain
title Models of the CI/CD pipeline
class PipelineConfig {
+python_versions: List[str]
+test_environments: List[str]
+security_checks: bool
+coverage_threshold: float
+validate()
}
class BuildArtifact {
+name: str
+version: str
+wheel_path: str
+sdist_path: str
+checksums: Dict[str, str]
+validate_integrity()
}
class TestResult {
+test_suite: str
+python_version: str
+passed: int
+failed: int
+coverage: float
+duration: float
+is_success(): bool
}
class SecurityReport {
+bandit_issues: List[Issue]
+safety_vulnerabilities: List[Vulnerability]
+severity_level: str
+is_secure(): bool
}
class DeploymentTarget {
+name: str
+url: str
+api_token: str
+environment: str
+deploy(artifact: BuildArtifact)
}
class ReleaseManager {
+version: str
+changelog: str
+artifacts: List[BuildArtifact]
+test_results: List[TestResult]
+security_report: SecurityReport
+deploy_to_test()
+deploy_to_production()
+create_github_release()
}
PipelineConfig ||--o{ TestResult
ReleaseManager *-- BuildArtifact
ReleaseManager *-- SecurityReport
ReleaseManager o-- DeploymentTarget
DeploymentTarget ..> BuildArtifact : uses
@enduml
Secrets Configuration
For the pipeline to work, you must configure the following secrets in GitHub:
GitHub Actions secrets
# Dans Settings > Secrets and variables > Actions
# Token PyPI pour la production
PYPI_API_TOKEN=pypi-...
# Token Test PyPI pour les pré-releases
TEST_PYPI_API_TOKEN=pypi-...
# Token GitHub pour créer les releases
GITHUB_TOKEN=(automatiquement fourni)
# Token Codecov (optionnel)
CODECOV_TOKEN=...
Generation of PyPI Tokens
# 1. Créer un compte sur PyPI et Test PyPI
# 2. Aller dans Account Settings > API tokens
# 3. Créer un token avec scope "Entire account" ou spécifique au projet
# 4. Format du token : pypi-AgEIcHlwaS5vcmc...
Local Development Scripts
To facilitate development, create utility scripts:
Makefile
.PHONY: install test lint format security build clean release-test release-prod
install:
pip install -e ".[dev]"
test:
pytest tests/ -v --cov=src/playlist_downloader
lint:
flake8 src tests
mypy src
format:
black src tests
security:
bandit -r src/
safety check
build:
python -m build
twine check dist/*
clean:
rm -rf build/ dist/ *.egg-info/
find . -type d -name __pycache__ -delete
find . -name "*.pyc" -delete
release-test: clean build
twine upload --repository testpypi dist/*
release-prod: clean build
twine upload dist/*
pre-commit: format lint test security
@echo "✅ Prêt pour commit"
Version script
#!/usr/bin/env python3
"""Script pour gérer les versions du projet."""
import sys
import subprocess
from pathlib import Path
def get_current_version():
"""Récupère la version actuelle depuis git."""
try:
result = subprocess.run(
["git", "describe", "--tags", "--abbrev=0"],
capture_output=True,
text=True,
check=True
)
return result.stdout.strip()
except subprocess.CalledProcessError:
return "0.0.0"
def create_version_tag(version, message=None):
"""Crée un tag de version."""
if not version.startswith('v'):
version = f'v{version}'
tag_message = message or f"Release {version}"
subprocess.run(["git", "tag", "-a", version, "-m", tag_message], check=True)
print(f"✅ Tag {version} créé")
# Push le tag
subprocess.run(["git", "push", "origin", version], check=True)
print(f"✅ Tag {version} poussé vers origin")
if __name__ == "__main__":
if len(sys.argv) < 2:
current = get_current_version()
print(f"Version actuelle: {current}")
print("Usage: python version.py <new_version> [message]")
sys.exit(1)
new_version = sys.argv[1]
message = sys.argv[2] if len(sys.argv) > 2 else None
create_version_tag(new_version, message)
Best Practices and Recommendations
Semantic versioning
Use semantic versioning (SemVer) :
-
MAJOR.MINOR.PATCH(ex: 1.2.3) -
`MAJOR`incompatible changes
-
MINOR: new compatible features -
`PATCH`compatible bug fixes
Branching Strategy
main ──●──●──●──●──●────●── (releases stables)
/ / /
develop ──●──●──●──●──●──●──●──●── (développement)
/ / /
feature/xxx ●──●──●──●──●──/ (fonctionnalités)
Tests and Coverage
-
Minimum code coverage: 85%
-
Unit tests for the business logic
-
Integration tests for the adapters
-
End-to-end tests for the CLI
Security
-
Automatic dependency scanning (Safety)
-
Static code analysis (Bandit)
-
Secrets are never in the code
-
Using specific PyPI tokens
Monitoring and Observability
Pipeline metrics
# .github/workflows/metrics.yml
name: Pipeline Metrics
on:
workflow_run:
workflows: ["CI", "Release"]
types: [completed]
jobs:
metrics:
runs-on: ubuntu-latest
steps:
- name: Collect metrics
run: |
echo "Pipeline: ${{ github.event.workflow_run.name }}"
echo "Status: ${{ github.event.workflow_run.conclusion }}"
echo "Duration: ${{ github.event.workflow_run.updated_at - github.event.workflow_run.created_at }}"
# Envoyer vers système de monitoring
Notifications
# Ajout dans les workflows pour notifications
- name: Notify on failure
if: failure()
uses: 8398a7/action-slack@v3
with:
status: failure
text: "❌ Pipeline failed for ${{ github.repository }}"
env:
SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK }}
Conclusion
This complete CI/CD pipeline for Python provides:
-
Full automationfrom code validation to publication
-
Security: automatic scans and secure secret management
-
Qualitymulti-version tests, linting and code coverage
-
Reliability: progressive deployment via Test PyPI
-
Traceability: artifacts, reports and releases GitHub
Adopting these practices ensures a robust and professional delivery process for your Python CLI applications, making it easier to maintain and evolve your projects in the long term.