Show disk usage of every derivation

[doronbehar]

I'd like to use nix-query-tree-viewer to see what packages take up most of the disk space in my system. If I run:

nix-query-tree-viewer /nix/store/i3qjymii00vxc124xal792lvcnvddcvb-system-path/

That's nice - I can see all of my derivations that are directly referenced by my configuration.nix. In the table showing up, it could be awesome to see a disk usage column showing the total disk usage of all of the derivations referenced per derivation.

Perhaps for this to be a bit fast, cache needs to be utilized for every store path and the total disk usage should be computed from according to the derivation path.

[cdepillabout]

This would be really neat!

Right now, nix-query-tree-viewer just shows the output of nix-store --query --tree, but adding additional information (like disk usage) would be great.

I'd be happy to accept a PR adding this functionality. It would ideally be behind a GUI toggle switch so you could make it not show disk usage.

[cdepillabout]

nix-tree does something like this.