inventory: update the default ignored extensions for inventory directories - #4077

SUMMARY

The "Using inventory directories and multiple inventory sources" section of the dynamic inventory guide lists the file extensions that Ansible ignores in an inventory directory:

~, .orig, .bak, .ini, .cfg, .retry, .pyc, .pyo

This list is out of date:

• ansible-core 2.19 removed .ini from the default INVENTORY_IGNORE_EXTS (changelog: "INVENTORY_IGNORE_EXTS config, removed ini from the default list ..."). The default in lib/ansible/config/base.yml is now REJECT_EXTS + ['.orig', '.cfg', '.retry'].
• The list leaves out the other entries that come from REJECT_EXTS (.swp, .rpm, .md, .txt, .rst).

This PR:

• replaces the list with the current default and links to the INVENTORY_IGNORE_EXTS entry in the configuration reference;
• adds a note about the .ini change. Before 2.19, inventory/hosts.ini was skipped without any warning when the directory was passed with -i. Since 2.19 it is read, and a non-inventory .ini file in the directory (for example the configuration file of an inventory script) is now parsed and produces warnings. The note also says that setting inventory_ignore_extensions replaces the default list instead of adding to it.

ISSUE TYPE

• Docs Pull Request

COMPONENT NAME

docs/docsite/rst/inventory_guide/intro_dynamic_inventory.rst

ADDITIONAL INFORMATION

I checked the behavior with ansible-core 2.16.3 (Ubuntu 24.04 package) and with ansible-core 2.21.5 (run from the v2.21.5 tag), Python 3.12, using the same directory:

inventory/
  hosts.ini   # [web] web1
  db          # [db] db1
  cache.yml   # cache group with cache1

# ansible-core 2.16.3
$ ansible-inventory -i inventory --graph
@all:
  |--@ungrouped:
  |--@cache:
  |  |--cache1
  |--@db:
  |  |--db1
$ ansible-config dump | grep INVENTORY_IGNORE_EXTS
INVENTORY_IGNORE_EXTS(default) = ('.pyc', '.pyo', '.swp', '.bak', '~', '.rpm', '.md', '.txt', '.rst', '.orig', '.ini', '.cfg', '.retry')

# ansible-core 2.21.5
$ ansible-inventory -i inventory --graph
@all:
  |--@ungrouped:
  |--@cache:
  |  |--cache1
  |--@db:
  |  |--db1
  |--@web:
  |  |--web1
$ ansible-config dump | grep INVENTORY_IGNORE_EXTS
INVENTORY_IGNORE_EXTS(default) = ['.pyc', '.pyo', '.swp', '.bak', '~', '.rpm', '.md', '.txt', '.rst', '.orig', '.cfg', '.retry']

With 2.16.3 the web group is missing and nothing is printed about hosts.ini.

An inventory script next to its own .ini configuration file (myinv.py + myinv.ini containing [myinv] and regions = us-east-1) is silent with 2.16.3. With 2.21.5 it prints Failed to parse inventory with 'ini' plugin ... Expected key=value host variable assignment, got: us-east-1 and Unable to parse .../myinv.ini as an inventory source, and adds an empty myinv group.

With ANSIBLE_INVENTORY_IGNORE=.ini on 2.21.5, hosts.ini is skipped but a notes.txt file in the same directory is parsed, so the setting replaces the default list. That is why the note says "the list above plus .ini".

I could not build the docs locally. The new :ref: target, INVENTORY_IGNORE_EXTS, is already used in intro_inventory.rst.

If you prefer, I can also add a short entry about this change to the ansible-core 2.19 porting guide, which does not mention it.

This change was drafted with AI assistance and reviewed by me.

🤖 Generated with Claude Code