Recursively search through flake inputs · nix

I recall @Srid mentioning this before, but I don’t seem to recollect. For example, if I have a flake in project-a and this has project-b in its inputs, project-b in turn depends on project-c in its flake. My question is, how can I find if project-a depends on project-c without having to go through each of the flake. I want something like nix why-depends but for flake inputs.

Srid (Jan 03 2024 at 13:23):

Unsure, but there is nix flake metadata which dumps the tree of inputs. It takes --json to produce a JSON output, so something can be built off it. Also nix-browser can (be made to) do this too, but a CLI would be nice.

Tim DeHerrera (Jan 07 2024 at 23:34):

fwiw, for quickly traversing inputs in the flake you can simply load the flake in a repl, and a top-level inputs attribute exists for quickly traversing the inputs of a flake

Shivaraj B H (Jan 08 2024 at 13:42):

Hey Tim, thanks for that, I am aware that I can traverse through the entire graph of the inputs, i.e if I know the path to whatever input I am looking for. I was looking for a solution, that given an input, gives me the pinned version for that input in the dependency graph and the path to reach to that node in the graph.

$ nix flake metadata --json | jq '.. | ."hedis"? | select( . != null )'

{
  "flake": false,
  "locked": {
    "lastModified": 1689234100,
    "narHash": "sha256-J4mqtraMzLJguL0BwMUETeBpNJXRf86E2ZaP9xx+4tY=",
    "owner": "juspay",
    "repo": "hedis",
    "rev": "77bf501da57639a60728b577e1c3780f70ddb418",
    "type": "github"
  },
  "original": {
    "owner": "juspay",
    "repo": "hedis",
    "rev": "77bf501da57639a60728b577e1c3780f70ddb418",
    "type": "github"
  }
}
"hedis"

Now, what if I want to get the path to reach this node, I can still use jq to do this, thanks to this solution from stackoverflow:

nix flake metadata --json | jq -c 'paths | select(.[-1] == "hedis")'

["locks","nodes","euler-hs","inputs","hedis"]
["locks","nodes","hedis"]

Srid (Jan 08 2024 at 17:12):

Nice one; here's another example (shared-kernel is transitively used by two other flakes, in addition to direct reference by the root flake; though the output doesn't say whether they all are pinned at same rev):

❯ nix flake metadata --json github:nammayatri/nammayatri | jq -c 'paths | select(.[-1] == "shared-kernel")'
["locks","nodes","beckn-gateway","inputs","shared-kernel"]
["locks","nodes","namma-dsl","inputs","shared-kernel"]
["locks","nodes","root","inputs","shared-kernel"]
["locks","nodes","shared-kernel"]

Shivaraj B H (Jan 08 2024 at 17:16):

Srid (Jan 08 2024 at 17:18):

You could wrap all of this in a pkgs.writeShellApplication and make it a flake-app runnable as, for instance, nix run github:shivaraj-bh/search-flake-inputs github:nammayatri/nammayatri shared-kernel

Srid (Jan 08 2024 at 17:19):

Shivaraj B H (Jan 08 2024 at 17:32):

I will probably come up with a more prettified output for this along with displaying a correspond short rev for the node in question, then making a flake-app around it would make sense

Srid (Jan 08 2024 at 17:33):

Shivaraj B H (Jan 15 2024 at 14:29):

Srid (Jan 16 2024 at 05:32):

tgunnoe (Feb 05 2024 at 21:04):

Shivaraj B H (Feb 06 2024 at 03:45):

I was planning to announce it but was wondering if I could make a general purpose search application in rust. It will be able to search outputs, inputs and can be made extensible to search much more.

Shivaraj B H (Feb 06 2024 at 03:46):

Maybe I should announce it at its current state and then later launch a successor that will deprecate this.

Stream: nix

Topic: Recursively search through flake inputs

Shivaraj B H (Jan 03 2024 at 09:49):