Generate semver tags for docker images

Semver is nice. The somewhat tricky part is allowing a service to be pinned to a specific MAJOR version and then tagging your released docker images accordingly.

Given we have the following tags in our repo:

• 0.1.0
• 0.2.0
• 0.3.0

And we then build 0.2.1 - what tags should be applied?

This tools tries to generate those tags. It'll spit out: 0.2 and 0.2.1. It will not touch the 0 tag as this should still point to 0.3.0.

So, in your kubernetes defintions you might then deploy $ARTFACT:0.2 and you'll get updates for the 0.2 branch.

Handling of latest is so simple that you don't need any tooling. The tricky bits are sticking on a MAJOR or MINOR version.

The regular expression used is taken from semver.org.

Usage

Find a way to get a hold of your current tags.

$ cat EXISTING_TAGS | python3 semver-tag.py 0.2.1 

Complete:

echo "0.1.0
0.2.0
0.3.0" | python3 semver-tag.py 0.2.1
0.2.1 0.2

I'm using this to in the scripts that apply tags.

You'll need to integrate this with your registry somehow.

Note that this tool hasn't been given much testing. However, as I found nothing like it I thought it might make sense to publish it. File and issue if you have any comments.

Bugs and weird stuff:

Ironically there is no versioning of this script. I suggest you copy and adapt.