Incremental building

[infinisil]

How can Nix do incremental builds?

Could include:

• Derivation-based incrementality
• The new pkgs.checkpointBuildTools
• Ccache
• Experimental Dynamic derivations
• edolstra's nix-ccache

[infinisil]

We decided to focus on this topic for this weeks Nix Hour, this Tuesday at 18:00 CET! If anybody has any extra questions about this topic, either:

• Ask them in this issue in advance with a comment
• Join the livestream and use the chat to ask questions live

[tcurdt]

Questions:

• Even with 100% of the inputs cached it seems like the evaluation of a derivation can take quite some time - why?
• Understanding the build output in more detail would be nice.
  [1/2/37 built, 14/42/66 copied (86.9/251.3 MiB), 24.1/59.6 MiB DL] fetching zstd-1.5.5-man from https://cache.nixos.org
  Especially the 1/2/37 and 14/42/66 in the above case.
• What's the best way to minimize builds from source on deployments (is cachix the only solution?)

[infinisil]

@tcurdt We touched upon your questions at 48:26 :)

Since we didn't get through everything, we'll focus on this topic again for this weeks Nix Hour, this Tuesday at 18:00 CET! If anybody has any extra questions about this topic, either:

• Ask them in this issue in advance with a comment
• Join the livestream and use the chat to ask questions live

[tcurdt]

@tcurdt We touched upon your questions at 48:26 :)

Sorry, I didn't make the live steam.
But that was super helpful. Thanks!

Still so much more to learn 🙄