NewPkg loads Pkg structure from file.

NewPkgfile loads Pkgfile from `[]byte` contents.

Alpine variant uses Alpine as base image for the build.

Scratch variant uses scratch image as base image for the build.

Dependency on another image or stage.

Finalize is a set of COPY instructions to finalize the build.

Pkg represents build instructions for a single package.

Pkgfile describes structure of 'Pkgfile'.

Source describe build source to be downloaded.

Step describes a single build step.

Dependencies is a list of Depency.

Environment is a set of environment variables to be set in the step.

Install is a list of Alpine package names to install.

Instruction is a single shell command.

Instructions is a list of shell commands.

Shell is a path to the shell used to execute Instructions.

Sources is a collection of Source.

Steps is a collection of Step.

Variant is a kind of base build image.