Buildout

Buildout, or zc.buildout, is an open-source tool for automating the assembly and deployment of Python applications. It reads a configuration file and uses recipes to assemble a complete runtime environment, including dependencies, configuration files, and executable scripts. Buildout emphasizes reproducibility: a single configuration file set can reproduce the same environment across machines.

Central to Buildout are configuration files, typically named buildout.cfg. The main [buildout] section declares where to install parts, eggs, and downloads; the [versions] section pins exact versions of dependencies; and the [parts] section lists components to install. Each part uses a recipe that defines how to fetch, install, and configure software. Eggs, a form of Python package, are resolved from an index or repository and placed in an isolated location, commonly within a “parts” directory. After bootstrap, running bin/buildout resolves dependencies, downloads required eggs, runs each part’s recipe, and creates executable scripts in the bin directory.

Typical workflows involve writing buildout.cfg with desired parts, possibly using a bootstrap script, then running buildout to produce a reproducible environment, ready for development or deployment. Buildout often creates a Python environment separate from the system Python, though it can be configured to integrate with virtual environments or system Python.

Origins and usage: Buildout was developed in the Zope ecosystem and has been widely adopted in Python projects, most notably the Plone content management system. It supports extensibility through a large set of community recipes, enabling tasks such as web server configuration, application server integration, and asset compilation.

Strengths include declarative, reproducible environments and strong packaging control; limitations include complexity and longer setup times, with several newer tooling options gaining popularity in recent years.