3d ago

selfh.st - dockcheck: A CLI Tool for Updating Container Images

selfh.st

dockcheck: A CLI Tool for Updating Container Images

I just has the honors of writing a guest article on selfh.st about my ever so slowly evolving project, dockcheck.

15 comments

Oh that's neat, really liking the matrix notifications. Now to make it a systemd service on all my hosts.
- Oh nice, yeah I havn't thought about suggesting a systemd-service thats neat! If you'd like you could contribute it as a discussion/suggestion/PR if you land on liking it, thatd be lovely.
  With the image backups in the next release you could maybe even build some kind of auto rollback functionality.
  
  Sure I can do that. I make packages too, would you think your project could use AUR, deb, rpm and/or snap packages?
Is this a replacement for Watchtower?
- This question is usually asked a lot.
  This started as a project to prove that you could check for updates without first pulling every new image to compare against, while that's not why it kept get getting traction my original answer to this question still seems true:
  From Watchtower Docs - Arguments
  Due to Docker API limitations the latest image will still be pulled from the registry.
  And:
  Do not pull new images. When this flag is specified, watchtower will not attempt to pull new images from the registry. Instead it will only monitor the local image cache for changes
  It's also a different approach. With dockcheck you'd run it and then make the choice what you'll update there and then. Selectively choosing exactly what containers to update at the moment. Or have it completely unattended auto update a selection of images.
  With the notifications, you can get notified and then have a sitdown and auto-update what you choose.
  It's just different workflows and options.
  The upcoming release will also add a new option to backup the image being updated and then autoprune old backups after N days. To allow for easy rollback if a new image breaks.
  
  Thanks for the detailed explanation. Will try to see how it fits my setup when I get a chance, but I have been wanting to move away from Watchtower as it is no longer maintained. Good to know there is an alternative, and from what you describe I like your approach. Having to opt-out of updates in Watchtower never really sat right with me- Watchtower clutter is okay in compose files that actually want something to do with Watchtower...
Does this check for version tags as well or only updates to the current tag?
Like the current container uses an image with the tag :0.1.0 or :v0.1.0 but :0.2.0 is available on the registry.
- Sadly no, only within the scope of the tag specified in the compose.
  Renovate, WUD or Diun might be other options for that!
- If you want automatic updates over major versions most images will have the :latest tag for that.
  
  I don't really want automatic updates, I want a notification once a month with all images that have a newer :latest available or if versionised, when a image with a newer version is available.
I absolutely adore dockcheck. Thank you for your work.
Perfect and just what I needed!

15 comments