Preseeds

Introduction

It is possible to pass configuration preseeds when creating a new project with mxmake init. This is useful if you have recurring default settings when creating projects with mxmake.

Preseeds are contained in yaml files and have the following format:

# topics to include
topics:
  # include topic core
  core:
    # include domain mxenv
    mxenv:
      # Minimal UV configuration - UV downloads Python automatically!
      PYTHON_PACKAGE_INSTALLER: uv
      UV_PYTHON: "3.14"
  qa:
    # include domains from qa topic but do not override default settings
    ruff:
    test:
    coverage:
# generate mx ini if not exists
mx-ini: true
# generate CI files from templates
ci-templates:
- gh-actions-test

Now initialize the project with the preseeds:

$ mxmake init -p preseeds.yaml

UV Package Installer

When PYTHON_PACKAGE_INSTALLER is set to uv, mxmake automatically detects whether UV is installed globally on your system.

Important

When using UV, you should explicitly set UV_PYTHON to specify which Python version UV should use. While UV_PYTHON currently defaults to PRIMARY_PYTHON for backward compatibility, relying on this default is not recommended and may change in future versions.

The UV_PYTHON setting accepts version specs like 3.13, 3.14, or cpython@3.14:

# Minimal UV configuration (recommended)
topics:
  core:
    mxenv:
      PYTHON_PACKAGE_INSTALLER: uv
      UV_PYTHON: "3.14"  # UV downloads this Python version

Note: When using UV with UV_PYTHON explicitly set:

• PYTHON_MIN_VERSION is not needed (validation skipped with global UV)

• PRIMARY_PYTHON is not needed (only used if UV_PYTHON is not set)

For traditional pip-based workflows, you would set:

# Traditional pip configuration (requires Python pre-installed)
topics:
  core:
    mxenv:
      PRIMARY_PYTHON: python3.12
      PYTHON_PACKAGE_INSTALLER: pip  # default

Examples

Create a simple Python project

mxmake was made for the easy management of Python projects.

This example shows how to create a very minimal project structure to build on. [mxdev][https://pypi.org/project/mxdev/] is integrated to manage versions, sources and more.

Preconditions for this example: uv is installed in the PATH.

Use uv init hello-world to generate a minimal skeleton package.

Enter the hello-world- directory and create a file preseed.yaml:

topics:
  core:
    mxenv:
      PYTHON_PACKAGE_INSTALLER: uv
      UV_PYTHON: "3.14"  # UV downloads Python 3.14
    sources:
  qa:
    ruff:
    mypy:
    test:

mx-ini: true

Then run:

uv mxmake init -p preseed.yaml

Edit the mx.ini and insert after the first line a new line: main-package = -e ..

Now run:

make install

Now you have a basic environment to build on. make format wont work, because it looks in the ./src directory, but this can be fixed by restrcuturing the code. You may want to use a different skeleton generator than “uv” here.

Create a Makefile for a simple Plone backend

Plone is an enterprise CMS written in Python (backend) and Javascript (frontend). mxmake helps to create the backend. It helps to develop and manage code for integrations and distributions, Plone-add-ons and the Plone-core-development itself.

Preconditions for this example: uv is installed in the PATH.

Go in a fresh directory and create a file plone-preseed.yaml:

topics:
  core:
    base:
      RUN_TARGET: zope-start
    mxenv:
      PYTHON_MIN_VERSION: "3.13"
      PYTHON_PACKAGE_INSTALLER: uv
      UV_PYTHON: "3.13"
  applications:
    zope:
    plone:
mx-ini: true

Run:

mxmake init -p plone-preseed.yaml
echo "-c https://dist.plone.org/release/6.1-latest/constraints.txt" >requirements.txt
echo "Plone" >>requirements.txt

In the

• 1st line the Makefile and the mx.ini configuration is generated,

• 2nd line a Python requirements is created with a reference to a Plone release file, pinning the versions,

• 3rd line the Plone package is declared as the main package.

Now “make” is now ready to run.

After the first command watch out for a line with the generated password. It looks like so:

Generated password for initial user ‘admin’ is: SOME-CRYPTIC-PASSWORD

Execute:

make plone-site-create
make run

In your browser go to localhost:8080. There runs a Plone with a backend ready for Volto (the frontend application for Plone) installed.

This can be combined with the above example for a Python package to create self-contained reproducible environments for development and deployment.