Dockerfile improvements: add `DEBIAN_FRONTEND=noninteractive`, size and readability

[pataquets]

• Add DEBIAN_FRONTEND=noninteractive (very recommended)
• Do package cache & index cleanup after apt-get (size)
• Readability: expand and sort build deps (grouped by tools & libs).
• Readability: add some spacing between build stages.

Pending (needs feedback after merging this in):

• Add an ENTRYPOINT
• Speed up successive, repeated builds by using build cache (useful for development). Sorting build steps by more/less frequently changed files needed.

[abique]

Thank you very much!

[pataquets]

Happy to help, @abique. Thanks to you for sharing! Do you have any advice on how to speed up repeated builds before I give it a stab?

[abique]

For Docker? I don't know it was a contribution, I'm not strong with Docker.

[pataquets]

I wasn't meaning for Docker, sorry. I was asking for/if the build process can be broken in smaller steps which can be reordered for speeding up repeated builds (for development scenario). Example: 1.- Adding/downloading deps/libs 2.- Building libs 3.- Building main binary and linking That would allow leveraging the Docker build cache, as each step would be a cache bust only if files for that step have changed, so only last step would be re-run most of the time (except lib/deps changes).