ansible/changelogs/fragments/79945-host_group_vars-impro...

bugfixes:
  - Cache host_group_vars after instantiating it once and limit the amount of repetitive work it needs to do every time it runs.
  - Call PluginLoader.all() once for vars plugins, and load vars plugins that run automatically or are enabled specifically by name subsequently.
deprecated_features:
  - Old style vars plugins which use the entrypoints `get_host_vars` or `get_group_vars` are deprecated. The plugin should be updated to inherit from `BaseVarsPlugin` and define a `get_vars` method as the entrypoint.
optimize host_group_vars and vars plugin loading (#79945) * Improve host_group_vars efficiency: * normalize the basedir with `os.path.realpath()` once and cache it * cache missing paths/files * reduce the calls to `isinstance` Add a couple more general improvements in vars/plugins.py get_vars_from_path(): * call `PluginLoader.all()` once for vars plugins and reload specific plugins subsequently * don't reload legacy/builtin vars plugins that are not enabled Add a test for host_group_vars and legacy plugin loading Co-authored-by: Matt Davis <mrd@redhat.com> * changelog * Add a new is_stateless attribute to the vars plugin baseclass update integration tests to be quieter and use the same test pattern Fix deprecation and adjust test that didn't catch the issue (deprecation only occured when the value was False) move realpath cache to host_group_vars (do not smuggle call state as instance data) refactor under a single 'if cache:' statement Call os.path.isdir instead of always calling os.path.exists first. Just call os.path.exists to differentiate between missing and non-directory. remove call to super(VarsModule, self).get_vars() use the entity name as the cache key instead of variable location Remove isinstance checks and use a class attribute just in case any plugins are subclassing Host/Group Replace startswith by checking index 0 of the name instead, since host/group names are required * rename is_stateless to cache_instance to make it more clear what it does * add plugin instance cache using the path to plugin loader reduce loading stage option if a new instance isn't created don't require a known subdir on PluginLoader instantiation for backwards compatibility rename attribute again contain reading from/initializing cached instances to a plugin loader method * Deprecate v2 vars plugins * Refactor to use the cache in existing plugin loader methods Rename the attribute again Refactor host_group_vars with requested changes Make changelog a bugfixes fragment Add a deprecation fragment for v2 vars plugins. Add type hints * unbreak group_vars * Apply suggestions from code review * misc tweaks * always cache instance by both requested and resolved FQ name * add lru_cache to stage calculation to avoid repeated config consultation * handle KeyError from missing stage option --------- Co-authored-by: Matt Davis <mrd@redhat.com> 1 year ago			`bugfixes:`
			`- Cache host_group_vars after instantiating it once and limit the amount of repetitive work it needs to do every time it runs.`
			`- Call PluginLoader.all() once for vars plugins, and load vars plugins that run automatically or are enabled specifically by name subsequently.`
			`deprecated_features:`
			- Old style vars plugins which use the entrypoints `get_host_vars` or `get_group_vars` are deprecated. The plugin should be updated to inherit from `BaseVarsPlugin` and define a `get_vars` method as the entrypoint.