Split setup.py into more manageable ansible_x_facts modules

[bcoca]

Proposal: splting facts

Author: Brian Coca <@bcoca>

Date: 2018-01-01

• Status: New
• Proposal type: core
• Targeted release: future
• Associated PR: none
• Estimated time to implement: weeks

Motivation

Create a better and more relevant fact gathering system.

Problems

• fact gathering is slooooow, mostly sequential and returns huge data sets of mostly ignorable data.

• The current 'fact gathering modules' (setup.py) is huge and hard to maintain, has a lot of code, most of it not used and even when used, the information retrieved might itself not be used.

• The 'gather_facts' action allows for configurable and multiple 'fact gathering plugins', even running in parallel, but to be effective it would require multiple plugins instead of the existing monolithic setup.

• The ansible engine slows down the more data per host we have, current fact gathering maximizes this data even when not needed.

Solution proposal

• Leverage the new gather_facts action to use multiple smaller and more targeted modules.
• Split setup.py into multple modules that each do more logical subsets of the whole (but keep setup.py for backwards compatibility)
• Switch the default gathering to use the new modules with a smaller subset

Example new ansible_min_facts module

#!/usr/bin/python
# -*- coding: utf-8 -*-
# (c) Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function


DOCUMENTATION = '''
---
module: min_facts
version_added: histerical
description:
    - Fact gathering module that allows for a the minimal facts you should know about a system
    - Trying to define 'minimal' is fun! right now platform, distribution and lsb
short_description: Gathers minimal set of facts about remote hosts
options:
    gather_subset:
        description:
            - "If supplied, only the facts for the specified subsets is gathered"
            - Possible values are 'all', 'lsb', 'distribution' and 'platform'
        type: list
        elements: str
        default: "all"
extends_documentation_fragment:
  -  action_common_attributes
  -  action_common_attributes.facts
attributes:
    check_mode:
        support: full
    diff_mode:
        support: none
    facts:
        support: full
    platform:
        platforms: posix
'''
 EXAMPLES = """
# Display facts from all hosts and store them indexed by I(hostname) at C(/tmp/facts).
# ansible all -m ansible.builtin.min_facts --tree /tmp/facts
"""
RETURN = r'''
architecture:
    description: System CPU architecture
    returned: success (platform)
    type: str
    sample: "x86_64"
distribution:
    description: Name of your OS distribution
    returned: success (distribution)
    type: str
    sample: "Gentoo"
distribution_file_parsed:
    description: Was the expected distribution information file was parsed?
    returned: success (distribution)
    type: bool
    sample:  true
distribution_file_path:
    description: File path to distribution information file
    returned: success (distribution)
    type: str
    sample:  "/etc/os-release"
distribution_file_variety:
    description: Type of distribution information file
    returned: success (distribution)
    type: str
    sample: "NA"
distribution_major_version:
    description: OS distribution version 'major' version number
    returned: success (distribution)
    type: str
    sample: "2"
distribution_release:
    description: Distribution OS release name
    returned: success (distribution)
    type: str
    sample: "n/a"
distribution_version": "2.8",
    description: Full OS distribution version
    returned: success (distribution)
    type: str
    sample: "2.8"
domain:
    description: domain part of the fully qualified hostname
    returned: success (platform)
    type: str
    sample: "example.com"
fqdn:
    description: Fully qualified domain name
    returned: success (platform)
    type: str
    sample: "myhost.example.com"
hostname:
    description: the left most part of the nodename ('.' as separator)
    returned: success (platform)
    type: str
    sample: "myhost"
kernel:
    description: kernel information
    returned: success (platform)
    type: str
    sample: "5.18.5-gentoo"
kernel_version:
    description: Full kernel compile tag
    returned: success (platform)
    type: str
    sample: "#1 SMP PREEMPT_DYNAMIC Tue Jun 21 20:40:20 EDT 2022"
lsb:
    description: set of Linux Standard Base OS distributino information
    returned?: success(lsb)
    type: complex
    sample:
        "lsb": {
            "codename": "n/a",
            "description": "Gentoo Base System release 2.8",
            "id": "Gentoo",
            "major_release": "2",
            "release": "2.8"
        }
machine:
    description: type of machine (architecture?)
    returned: success (platform)
    type: str
    sample: "x86_64"
machine_id:
    description: unique? machine identifier
    returned: success (platform)
    type: str
    sample: "474bdfd137caca678ff2ebdf00000ed9"
nodename:
    description: the full hostname as configured
    returned: success (platform)
    type: str
    sample: "myhost"
os_family:
    description: The 'family' this OS distribution si part of
    returned: success (platform)
    type: str
    sample:  "Gentoo"
python_version:
    description: The version of python used to execute the fact gathering plugin
    returned: success (platform)
    type: str
    sample: "3.9.13"
system:
    description: System OS
    returned: success (platform)
    type: str
    sample: Linux
userspace_architecture:
    description: User library architecture
    returned: success (platform)
    type: str
    sample: "x86_64"
    sample: "64"
'''

from ansible.module_utils.basic import AnsibleModule
from ansible.module_utils.facts.system.distribution import DistributionFactCollector
from ansible.module_utils.facts.system.platform import PlatformFactCollector
from ansible.module_utils.facts.system.lsb import LSBFactCollector


def main():
    module = AnsibleModule(
        argument_spec=dict(
            gather_subset=dict(default=["all"], required=False, type='list', elements='str'),
        ),
        supports_check_mode=True,
    )
    result = {}
    collectors = [DistributionFactCollector, PlatformFactCollector, LSBFactCollector]
    for c in collectors:
        result.update(c().collect(module))

    module.exit_json(ansible_facts=result)

if __name__ == '__main__':
    main()

Documentation (optional)

This is also a good chance to ad RETURN documentation to each module, a much easier to accomplish task since we divide the currently 'huge' setup.py