crossbuilder

README

Crossbuilder

Crossbuilder is a tool that allows the generation of Crossplane XRDs and compositions from go code.

This tool builds on mistermx/crossbuilder to provide two tools, xrd-gen and xrc-gen which can be used to build crossplane definitions and compositions.

XRD Generation

Crossbuilder's xrd-gen wraps around Kubebuilder and controller-gen but instead of generating CRDs (Custom Resource Definitions) it generates XRDs (Composite Resource Definitions) that are part of the Crossplane ecosystem.

Crossbuilder has every feature that Kubebuilder's CRD generator provides plus the ability to define XRD specific fields.

Take a look at the xrd-gen examples for more details.

Composition Generation

Warning Composition generation builds and executes code during runtime.

This can be dangerous as it may impact the system on which the code is being executed.

As a result, it is not recommended that these tools ever be installed on production or mission critical systems and instead, it is recommended that the tools be executed from inside a container environment with only the required directories mounted. See below for details.

Crossbuilder provides a toolkit that allows building compositions from Go and write them out as YAML.

Both Resource type compositions and Pipeline compositions are supported.

Since go is a statically typed language, Crossbuilder is able to perform additional validation checks, such as patch path validation, that is a common cause of errors when writing Crossplane compositions. This is only applicable when running xrc-gen against a Resource type composition. It is not applicable for running against a Pipeline mode composition as resources may come from custom composition functions and templates making them ineligible for build-time discovery.

Compositions are written as go plugins and must implement the CompositionBuilder interface.

package main

type builder struct {}

var Builder builder

func (b *builder) GetCompositeTypeRef() build.ObjectKindReference {
    // return object kind information
}

func (b *builder) Build(c build.CompositionSkeleton) {
    // implement pipeline here
}

The tool will look for all directories under compositions at the current location with a max depth of 1 and builds a plugin from each discovered directory, these are output to the plugins directory from where they will be loaded.