[new release] obuilder and obuilder-spec (0.2)

[talex5]

Run build scripts for CI

• Project page: https://github.com/ocurrent/obuilder
• Documentation: https://ocurrent.github.io/obuilder/

CHANGES:

• Add support for nested / multi-stage builds (@talex5 Rename stage type to t ocurrent/obuilder#48 Add support for nested / multi-stage builds ocurrent/obuilder#49).
  This allows you to use a large build environment to create a binary and then
  copy that into a smaller runtime environment. It's also useful to get better caching
  if two things can change independently (e.g. you want to build your software and also
  a linting tool, and be able to update either without rebuilding the other).

• Add healthcheck feature (@talex5 Add a healthcheck feature ocurrent/obuilder#52).

  • Checks that Docker is running.
  • Does a test build using busybox.

• Clean up left-over runc containers on restart (@talex5 Clean up left-over runc containers on restart ocurrent/obuilder#53).
  If btrfs crashes and makes the filesystem read-only then after rebooting there will be stale runc directories.
  New jobs with the same IDs would then fail.

• Remove dependency on dockerfile (@talex5 Remove dependency on dockerfile ocurrent/obuilder#51).
  This also allows us more control over the formatting
  (e.g. putting a blank line between stages in multi-stage builds).

• Record log output from docker pull (@talex5 Record log output from docker pull  ocurrent/obuilder#46).
  Otherwise, it's not obvious why we've stopped at a pull step, or what is happening.

• Improve formatting of OBuilder specs (@talex5 Improve formatting of OBuilder specs ocurrent/obuilder#45).

• Use seccomp policy to avoid necessary sync operations (@talex5 Use seccomp policy to avoid necessary sync operations ocurrent/obuilder#44).
  Sync operations are really slow on btrfs. They're also pointless,
  since if the computer crashes while we're doing a build then we'll just throw it away and start again anyway.
  Use a seccomp policy that causes all sync operations to "fail", with errno 0 ("success").
  On my machine, this reduces the time to apt-get install -y shared-mime-info from 18.5s to 4.7s.
  Use --fast-sync to enable to new behaviour (it requires runc 1.0.0-rc92).

• Use a mutex to avoid concurrent btrfs operations (@talex5 Use mutex to avoid concurrent btrfs operations ocurrent/obuilder#43).
  Btrfs deadlocks enough as it is. Don't stress it further by trying to do two things at once.

Internal changes:

• Improve handling of file redirections (@talex5 Record log output from docker pull  ocurrent/obuilder#46).
  Instead of making the caller do all the work of closing the file descriptors safely, add an FD_move_safely mode.

• Travis tests: ensure apt cache is up-to-date (@talex5 Travis tests: ensure apt cache is up-to-date ocurrent/obuilder#50).

[talex5]

The CI failures are due to conf-sqlite3 not installing on Oracle.

[camelus]

Commit: f40d43a

A pull request by opam-seasoned @talex5.

☀️ All lint checks passed f40d43a

• These packages passed lint tests: obuilder-spec.0.2, obuilder.0.1, obuilder.0.2

---

☀️ Installability check (+2)

• new installable packages (2): obuilder.0.2 obuilder-spec.0.2

[kit-ty-kate]

The CI failures are due to conf-sqlite3 not installing on Oracle.

Fixed in #17901

All green now, thanks!