promise-type-appstreams

A CFEngine custom promise type for managing AppStream modules on compatible systems.

Overview

The appstreams promise type allows you to manage AppStream modules, which are a key feature of RHEL 8+ and compatible systems. AppStreams provide multiple versions of software components that can be enabled or disabled as needed.

Features

• Enable, disable, install, and remove AppStream modules
• Support for specifying streams and profiles
• Automatic stream switching (upgrades and downgrades)
• Generic DNF configuration options support
• Audit trail support via handle and comment attributes

Installation

To install this promise type, copy the appstreams.py file to your CFEngine masterfiles directory and configure the promise agent:

promise agent appstreams
{
  interpreter => "/usr/bin/python3";
  path => "$(sys.workdir)/modules/promises/appstreams.py";
}

Usage

Ensure a module is enabled

bundle agent main
{
  appstreams:
      "nodejs"
        state => "enabled",
        stream => "12";
}

Ensure a module is disabled

bundle agent main
{
  appstreams:
      "nodejs"
        state => "disabled";
}

Ensure a module is installed with a specific profile

bundle agent main
{
  appstreams:
      "python36"
        state => "installed",
        stream => "3.6",
        profile => "minimal";
}

Ensure a module is removed

bundle agent main
{
  appstreams:
      "postgresql"
        state => "removed";
}

Reset a module to default

bundle agent main
{
  appstreams:
      "nodejs"
        state => "default";
}

Stream switching (upgrade or downgrade)

When a module is already installed with a different stream, the promise type automatically switches to the requested stream:

bundle agent main
{
  appstreams:
      "php"
        handle => "main_php_stream_82",
        comment => "Upgrade PHP from 8.1 to 8.2 for new features",
        state => "installed",
        stream => "8.2",
        profile => "minimal";
}

This will automatically switch from any currently installed stream (e.g., 8.1) to stream 8.2.

Using DNF options

You can pass generic DNF configuration options to control package installation behavior:

bundle agent main
{
  appstreams:
      "php"
        state => "installed",
        stream => "8.2",
        profile => "minimal",
        options => {
          "install_weak_deps=false",
          "best=true"
        };
}

This installs PHP 8.2 minimal profile without weak dependencies (like httpd).

Attributes

The promise type supports the following attributes:

• state (optional) - Desired state of the module: enabled, disabled, installed, removed, default, or reset (default: enabled)
• stream (optional) - Specific stream of the module to use. Set to default to use the module’s default stream.
• profile (optional) - Specific profile of the module to install. Set to default to use the module stream’s default profile.
• options (optional) - List of DNF configuration options as “key=value” strings (e.g., { "install_weak_deps=false", "best=true" }). Invalid options will cause the promise to fail.
• handle (optional) - CFEngine handle for the promise, recorded in DNF history for audit traceability.
• comment (optional) - CFEngine comment for the promise, recorded in DNF history for audit traceability.

Requirements

• CFEngine 3.18 or later
• Python 3
• DNF Python API (python3-dnf package)
• DNF/YUM package manager (RHEL 8+, Fedora, CentOS 8+)
• AppStream repositories configured