Engine Updates – custom docker images

[theflow]

We know that quite a few teams are using custom docker images as their base image, for example like this

FROM depfu/base:1.0.2-stretch

This makes it basically impossible for us to automatically detect that we need to update that image in the Dockerfile, since there is no relation to the ruby/nodejs version. But it also depends on someone updating the actual image to pull in the new version, so even if we would detect it, there are some workflow dependencies which make this quite tricky.

This is a known issue we're thinking about, but haven't really come up with a good solution yet. if you have any ideas, please let us know!

[klausmeyer]

This makes it basically impossible for us to automatically detect that we need to update that image in the Dockerfile, since there is no relation to the ruby/nodejs version.

Would it be possible to allow configuring a regexp per repo which would help you extracting that version info?
Maybe as some kind of "expert feature".

In our example we're using a custom version of the alpine based ruby base-images hosted on a internal docker registry:

FROM hub.mycompany.intern/baseimages/ruby:2.6.6-mysql

A (very naive) regex in that case might then be just:

/hub.mycompany.intern\/baseimages\/ruby:(.*)-mysql/

But it also depends on someone updating the actual image to pull in the new version, so even if we would detect it, there are some workflow dependencies which make this quite tricky.

IMHO this should be totally ok. One will still need to make sure the ruby version is available on all the target platforms anyways before merging the PR (assuming it's done manually). For example it also takes some time to have the ruby version available on:

• Travis CI (think they pull it from RVM)
• GitHub Actions (currently 2.7.2 isn't available there yet in the ruby-setup action)
• Heroku (might be the fastest to get ruby releases available ^^)
• Docker Hub (for the official image)