The Fedora CoreOS Config Transpiler (FCCT) translates human readable Fedora CoreOS Configs (FCCs) into machine readable Ignition Configs. See the getting started guide for how to use FCCT and the configuration specifications for everything FCCs support.

Internally, FCCT has a versioned base component which contains support for a particular Ignition spec version, plus distro-independent sugar. New base functionality is added only to the experimental base package. Eventually the experimental base package is stabilized and a new experimental package created. The base component is versioned independently of any particular distro, and its versions are not exposed to the user. Client code should not need to import anything from base.

Each FCC variant/version pair corresponds to a config package, which derives either from a base package or from another config package. New functionality is similarly added only to an experimental config version, which is eventually stabilized and a new experimental version created. (This will often happen when the underlying package is stabilized.) A config package can contain sugar or validation logic specific to a distro (for example, additional properties for configuring etcd).

Packages outside the FCCT repository can implement additional FCC versions by deriving from a base or config package and registering their variant/version pair with config.

config/ Top-level TranslateBytes() function that determines which config version to parse and emit. Clients should typically use this to translate FCCs.

config/common/ Common definitions for all spec versions, including translate options structs and error definitions.

config/*/vX_Y/ User facing definitions of the spec. Each is derived from another config package or from a base package. Each one defines its own translate functions to be registered in the config package. Clients can use these directly if they want to translate a specific spec version.

config/util/ Utility code for implementing config packages, including the (un)marshaling helpers. Clients don't need to import this unless they're implementing an out-of-tree config version.

base/ Distro-agnostic code targeting individual Ignition spec versions. Clients don't need to import this unless they're implementing an out-of-tree config version.

internal/ main, non-exported code.