Packaging/Python: Difference between revisions

Line 15:

You can now run <code>nix-shell</code> and it will drop you in a shell similar to the <code>python setup.py develop</code> mode which uses the local code in <tt>./path/to/source</tt> as input. <code>propagatedBuildInputs</code> will contain the packages you need in your project.

After you've finished developing you can replace the relative path with <code>fetchFromGitHub { ... }</code> or <code>[https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchpypi/default.nix fetchPypi] { ... }</code>.

== Testing out a module in a Python shell ==

Once you have your derivation written, you can create a [[Flakes|flake]] to give yourself a shell and easily test out the module you wrote the derivation for.

Create a <code>flake.nix</code> next to your derivation:<syntaxhighlight lang="nix">

{

description = "Dev shell using external derivation";

inputs = {

nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

flake-utils.url = "github:numtide/flake-utils";

};

outputs = { self, nixpkgs, flake-utils }:

flake-utils.lib.eachDefaultSystem (system:

let

pkgs = import nixpkgs { inherit system; };

python = pkgs.python3;

# replace ./default.nix with the path to your derivation, relative to this file

mypackage = pkgs.callPackage ./default.nix {

inherit (python.pkgs) buildPythonPackage package names of dependencies here;

lib = pkgs.lib;

};

in {

devShells.default = pkgs.mkShell {

buildInputs = [ python mypackage ];

};

});

}

</syntaxhighlight>Replace "mypackage" with your package name, and "package names of dependencies here" with a (space-separated) list of the dependencies you listed in your buildPythonPackage call.

Next, enter the devShell and launch a Python REPL:<syntaxhighlight lang="shell-session">

$ nix develop

$ python

Python 3.11.10 (main, Sep 7 2024, 01:03:31) [GCC 13.2.0] on linux

Type "help", "copyright", "credits" or "license" for more information.

>>> import mypackage

>>> # test things out...

</syntaxhighlight>

== Pip and Virtualenv enabled nix-shell ==

@@ Line 15: / Line 15: @@
 You can now run <code>nix-shell</code> and it will drop you in a shell similar to the <code>python setup.py develop</code> mode which uses the local code in <tt>./path/to/source</tt> as input. <code>propagatedBuildInputs</code> will contain the packages you  need in your project.
 After you've finished developing you can replace the relative path with <code>fetchFromGitHub { ... }</code> or <code>[https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchpypi/default.nix fetchPypi] { ... }</code>.
+== Testing out a module in a Python shell ==
+Once you have your derivation written, you can create a [[Flakes|flake]] to give yourself a shell and easily test out the module you wrote the derivation for.
+Create a <code>flake.nix</code> next to your derivation:<syntaxhighlight lang="nix">
+{
+  description = "Dev shell using external derivation";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+        python = pkgs.python3;
+        # replace ./default.nix with the path to your derivation, relative to this file
+        mypackage = pkgs.callPackage ./default.nix {
+          inherit (python.pkgs) buildPythonPackage package names of dependencies here;
+          lib = pkgs.lib;
+        };
+      in {
+        devShells.default = pkgs.mkShell {
+          buildInputs = [ python mypackage ];
+        };
+      });
+}
+</syntaxhighlight>Replace "mypackage" with your package name, and "package names of dependencies here" with a (space-separated) list of the dependencies you listed in your buildPythonPackage call.
+Next, enter the devShell and launch a Python REPL:<syntaxhighlight lang="shell-session">
+$ nix develop
+$ python
+Python 3.11.10 (main, Sep  7 2024, 01:03:31) [GCC 13.2.0] on linux
+Type "help", "copyright", "credits" or "license" for more information.
+>>> import mypackage
+>>> # test things out...
+</syntaxhighlight>
 == Pip and Virtualenv enabled nix-shell ==