Extensibility.md

Extensibility

Facter 4 has the following extensibility goals:

• Compatibility with 100% of existing Facter custom facts
• Compatibility with 100% of existing Facter external facts

The following sections discuss those goals in more depth.

Note that this doc is work-in-progress and should be updated as extensibility features are implemented, refined or ruled out.

Custom Facts Compatibility

Facter 4 will load custom facts from the following locations:

• Any Ruby source file in a facter subdirectory on the Ruby load path.
• Any Ruby source file in a directory specified by the FACTERLIB environment variable (delimited by the platform PATH separator).
• Any Ruby source file in a directory specified by the --custom-dir option to facter.

The following methods from the Facter API are currently supported by Facter 4:

From the Facter module:

• []
• add
• clear
• debug
• debugonce
• define_fact
• each
• fact
• flush
• list
• loadfacts
• log_exception
• reset
• resolve
• search
• search_path
• search_external
• search_external_path
• to_hash
• value
• version
• warn
• warnonce

From the Facter::Core::Execution module:

• which
• exec
• execute
• ExecutionFailure

From the Facter::Util::Fact class:

• define_resolution
• flush
• name
• resolution
• value

From the Facter::Util::Resolution module:

• confine
• exec
• has_weight
• name
• on_flush
• setcode
• which

From the Facter::Core::Aggregate module:

• aggregate
• chunk
• confine
• has_weight
• name
• on_flush

Please see the Facter Custom Facts Walkthrough for more information on using the Facter API.

External Facts Compatiblity

Facter 4 supports all 4 forms of "external facts" which Facter 3 supports:

• JSON files with the .json extension whose key-value pairs will be mapped to fact-value pairs.
• YAML files with the .yaml extension whose key-value pairs will be mapped to fact-value pairs.
• Text files with the .txt extension containing fact=some_value strings
• Executable files returning fact=some_value strings

Enable conversion of dotted facts to structured

By default Facter 4 treats the . in custom or external fact names as part of the fact name and not a delimiter for structured facts.

If you want to enable the new behaviour, that converts dotted facts to structured you need to set the following config:

global : {
    force-dot-resolution : true
}