chore: Speed up docker builds a bit by reducing layer count.

[iphydf]

This is especially noticeable on local builds (less so on the github workers).

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This change is 

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (d6d67d5) 73.77% compared to head (8328449) 73.68%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2603      +/-   ##
==========================================
- Coverage   73.77%   73.68%   -0.09%     
==========================================
  Files         148      148              
  Lines       30366    30366              
==========================================
- Hits        22401    22375      -26     
- Misses       7965     7991      +26     

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[nurupo]

Ok, I see where my confusion came from. I misread docker/build-push-action@v4 as docker/build-publish-action@v4. It's also that each analysis tool does that, not just one job.

So, each analysis tool job gathers the source files from the local git repo checkout and builds an image containing it, and then runs the tool-specific Docker build that uses that local image. No Dockerhub involved at all. That makes a lot more sense :)

[nurupo]

Somewhat curious as by how much does this speed up the local builds. It can't be more than 1-5 seconds on a modern computer with an ssd, can it? I would actually think that it makes them slower, since for every tool you run you now also run other/docker/sources/build which calls docker to build the source image, with the docker having to analyze the fs to see if any files have were modified/added/removed.

[nurupo]

LGFM, just want to get those conversations resolved (and possibly the speed-up question answered).

[iphydf]

Somewhat curious as by how much does this speed up the local builds. It can't be more than 1-5 seconds on a modern computer with an ssd, can it? I would actually think that it makes them slower, since for every tool you run you now also run other/docker/sources/build which calls docker to build the source image, with the docker having to analyze the fs to see if any files have were modified/added/removed.

Not everybody has SSD :). On SSD, it almost doesn't matter, but on HDD it's quite significant.

[iphydf]

It matters more when you run multiple of these docker builds in sequence, so you only need to build sources once.