fix(nix): Get python app version from new location (#23)

* feat(nix): use niv for channel management and versioning

* fix(nix): extract version from src/beku/version.py since it is no longer extractable from the pyproject.toml file

* Apply suggestions from code review

Co-authored-by: Natalie Klestrup Röijezon <nat@nullable.se>

* fix(nix): remove remaining references to pkg

* chore(nix): remove unused dependency

* chore(nix): extract version from src/beku/version.py via python

---------

Co-authored-by: Natalie Klestrup Röijezon <nat@nullable.se>

Author: NickLarsenNZ

.gitattributes

@@ -0,0 +1 @@
+nix/** linguist-generated

beku.nix

@@ -1,11 +1,19 @@
-{ python3 }:
-with python3;
+{ python3, runCommand, lib }:
 let
-  manifest = (pkgs.lib.importTOML ./pyproject.toml).project;
+  # I wish there was a better way. If the command fails, it is very hard to see 
+  # that the problem is here. Perhaps there is some way to evaluate it in python
+  # and reference __version__ directly?
+  version = builtins.readFile (runCommand "foo" { src = [ ./src ]; } ''
+    PYTHONPATH=$src ${python3}/bin/python -c 'import beku.version; print(beku.version.__version__)' > $out
+  '');
+  manifest = (lib.importTOML ./pyproject.toml).project;
 in
-pkgs.buildPythonApplication {
+python3.pkgs.buildPythonApplication {
   pname = manifest.name;
-  version = manifest.version;
+  # The version is no longer set in pyproject.toml, so we have to jump through
+  # hoops to extract it from a python script.
+  # version = manifest.version;
+  inherit version;
 
   format = "pyproject";
 
@@ -14,13 +22,14 @@ pkgs.buildPythonApplication {
     name = manifest.name;
   };
 
-  nativeBuildInputs = with pkgs; [
+  nativeBuildInputs = with python3.pkgs; [
     setuptools
   ];
 
-  propagatedBuildInputs = with pkgs; [
+  propagatedBuildInputs = with python3.pkgs; [
     jinja2
     pyyaml
   ];
 }
 
+

default.nix

@@ -1,4 +1,7 @@
-{ pkgs ? import <nixpkgs> {} }:
+{ sources ? import ./nix/sources.nix # managed by https://github.com/nmattia/niv
+, nixpkgs ? sources.nixpkgs
+, pkgs ? import nixpkgs {}
+}:
 
 {
   beku = pkgs.callPackage ./beku.nix {};