Overlay step

The component parts of a ROCK are built in a sequence of five separate steps: pull, overlay, build, stage and prime.

The overlay step is specific to ROCKs and is configured with overlay parameters. To learn more about pull, build, stage and prime see Rockcraft parts

Overlay Parameters

A part has three parameters that can be used to adjust how the overlay step works: overlay-packages, overlay-script and overlay-filter. overlay-packages and overlay (the filter parameter) behave much the same way as the related parameters on the STAGE step. overlay-script likewise behaves similarly to override-stage, including having access to the craftctl command.

An example parts section with overlay parameters looks as follows:

parts:
  part_with_overlay:
    plugin: nil
    overlay-packages:
      - ed
    overlay-script: |
      rm -f ${CRAFT_OVERLAY}/usr/bin/vi ${CRAFT_OVERLAY}/usr/bin/vim*
      rm -f ${CRAFT_OVERLAY}/usr/bin/emacs*
      rm -f ${CRAFT_OVERLAY}/bin/nano
    overlay:
      - bin
      - usr/bin

After running this part, the overlay layer (and the final package) will only contain ed as an editor, with vi/vim, emacs, and nano all having been removed.