Automatically pull if there is a newer base image?

[GrabbenD]

Is it possible to automatically detect updates for upstream images when doing podman build of a local Containerfile?

Example:

1. $ less Containerfile

   FROM archlinux:base
   RUN echo OK

2. $ podman build -f Containerfile
3. Skip cache if archlinux:base image is updated upstream

[vrothberg]

Thanks for reaching out. Have a look at the --pull flag.

[vrothberg]

Thanks for pointing that out, @GrabbenD.

I can confirm that the default is "missing". The man pages need to be updated. I will open a PR to fix that in a moment.

[GrabbenD]

That explains it, thanks!

Does newer option actually do anything?
There's no confirmation that current digests matches upstream in the logs (for reference: I'm using using :latest) 😕

[vrothberg]

newer only pulls the image if the upstream digest is different than the one in the local storage.

[GrabbenD]

Gotcha!

While playing around with this I noticed that -t name automatically tags as localhost/name:latest, if you specify FROM localhost/name:latest or FROM name:latest in Containerfile and use --pull=always it fails due to WARN[0000] Failed, retrying in 2s ... (1/3). Error: initializing source docker://localhost/name:latest: pinging container registry localhost: Get "https://localhost/v2/": dial tcp [::1]:443: connect: connection refused which isn't the case if you never specify --pull or use --pull=newer

[GrabbenD]

I went ahead and made bug reports for visibility

• [Docs] Outdated default for --pull in 'podman build' #20125
• https://github.com/containers/podman/issues/20126