umoci 0.0.0~rc2

umoci now has a stable UX, as well as proper documentation for the UX in
the form of generated man pages. Here's the full list of cool features:

• umoci v0.0.0-rc2 has support for rootless unpacking and repacking!
  cyphar/umoci#26
• It also has support for regular UID and GID mapping! cyphar/umoci#26
• Symlinks and other similarly tricky unpacking problems have been
  resolved. All symlink path components are resolved inside the root
  filesystem of the container during unpacking. cyphar/umoci#27
• Tag modification commands (such as umoci-tag(1), umoci-rm(1),
  umoci-ls(1)) have been implemented. cyphar/umoci#6 cyphar/umoci#40
• umoci-stat(1) has been implemented. Currently it only outputs history
  information, but this will change in the future. It has stable JSON
  output. cyphar/umoci#38
• umoci-init(1) and umoci-new(1) have been implemented, allowing for the
  creation of entirely new images from scratch. cyphar/umoci#5
  cyphar/umoci#42
• umoci-repack(1) and umoci-config(1) now automatically generate history
  entries (since the history is actually used by tooling like skopeo). In
  addition, the history mutation from umoci-config(1) has been removed
  because it was just unsafe. In order for users to be able to configure
  history entries' values, --history.* flags have been introduced.
  cyphar/umoci#
• umoci-unpack(1) now saves all of the important argument metadata
  provided to it inside the generated bundle. These saved arguments are
  loaded by umoci-repack(1) to make the workflow much more sane.
• --image and --from arguments have been combined into skopeo-style
  [:] arguments to --image. cyphar/umoci#39
• Errors encountered during generation of a delta layer now are
  correctly propagated. cyphar/umoci#33
• Hardlinks are now correctly unpacked as bone-fide hardlinks.
  cyphar/umoci#25
• Support for unpacking and configuring annotations (which is a
  v1.0.0-rc3 feature of the OCI image specification). There's still some
  work to be done upstream in making the unpacking procedure specified
  but this is as good as you're going to get for a while.
  cyphar/umoci#43
• umoci has full integration and unit testing. cyphar/umoci#12
• umoci now has validation integration tests to ensure that at every
  stage of a test we could stop and still have a completely valid OCI
  image and that every extracted bundle is a valid OCI runtime bundle.

This code is still being reworked (though much more slowly than before).
Hold off on using it anywhere until we hit the proper 0.0.0 release!

Signed-off-by: Aleksa Sarai [email protected]