v2.16.0

Changed

• A failing pre-update hook now aborts the update, as the Lifecycle Hooks
  wiki page documents. Exit 0 continues, exit 75 skips the update, and any
  other exit code, an exec error or a timeout stops it before the image
  backup and pull and clears the maintenance flag. An aborted update is
  recorded as failed in the container's update history and sends the
  update_failed notification, as a failed validation does. A skip with exit
  75 records nothing and sends no failure notification. Previously the failure
  was logged as a warning and the update went ahead. Post-update hook
  failures are still only logged (GitHub #86).

Fixed

• Lifecycle hooks set with the sentinel.hook.pre-update,
  sentinel.hook.post-update and sentinel.hook.timeout labels now run.
  Only hooks saved through the REST API were ever read, so label hooks were
  silently ignored. A hook saved through the API still wins for its phase.
  Sentinel now logs each hook it runs with its phase and source (label or
  store), logs at Debug when a container has none, and warns when a hook
  label has an empty value (the compose list form without =value) or the
  timeout label is not a whole number of seconds (GitHub #86).
• SENTINEL_HOOKS_WRITE_LABELS (Settings > Write hook labels) was saved but
  never used. It now writes a container's API-saved hooks onto the container
  Sentinel creates during an update, as sentinel.hook.* labels
  (GitHub #86).
• A hook that outlives its timeout no longer holds up the update: Sentinel
  stops waiting when the timeout expires. The command itself is not killed
  and may keep running inside the container (GitHub #86).
• POST /api/hooks/{container} accepts command as a shell string, run with
  /bin/sh -c like a label, as well as an array of arguments. The
  documented string form returned 400 (GitHub #86).
• The Settings page shows the value in effect for Lifecycle hooks, Write
  hook labels, Image cleanup, Dependency-aware updates and Auto-update
  :latest containers. It showed only a value saved in the UI, so an env var
  such as SENTINEL_HOOKS=true appeared as Off until the toggle was saved
  (GitHub #86).