override python27Packages.bepasty-server - nix

Question

to experiment with upstream changes i want to alter the src= attribute in pkgs.python27Packages.bepasty-server.
reading through https://nixos.org/nixpkgs/manual/#chap-functions there is no example how to do this for pythonPackages!
so i have tried the stuff below, which i found in some xml-code for the documentation. but it doesn't work ... which is the part where i need your help!
packageOverrides
idea
nixpkgs.config.packageOverrides = super: {
python27Packages.bepasty-server = (pkgs.python27Packages.bepasty-server.overrideAttrs (oldAttrs: {
src = pkgs.fetchgit {
url = "https://github.com/bepasty/bepasty-server";
sha256 = "1ziqshmsf0rjvdhhca55sm0x8jz76fsf2q4rwh4m6lpcf8wr0nps";
rev = "e2516e8cf4f2afb5185337073607eb9e84a61d2d";
};
}));
results in this:
building Nix...
building the system configuration...
error: attribute ‘gunicorn’ missing, at /nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/services/misc/bepasty.nix:5:14
(use ‘--show-trace’ to show detailed location information)
reducing the code
nixpkgs.config.packageOverrides = super: {
python27Packages.bepasty-server = pkgs.python27Packages.bepasty-server;
};
results in:
[root#nixdoc:~/nixpkgs]# nixos-rebuild build
building Nix...
building the system configuration...
error: attribute ‘gunicorn’ missing, at /nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/services/misc/bepasty.nix:5:14
(use ‘--show-trace’ to show detailed location information)
so it seems this won't work at all, but why?
systemPackages
in contrast, here it seems to be working:
environment.systemPackages = with pkgs; [
(python27Packages.bepasty-server.overrideAttrs (oldAttrs: {
src = pkgs.fetchgit {
url = "https://github.com/bepasty/bepasty-server";
sha256 = "1ziqshmsf0rjvdhhca55sm0x8jz76fsf2q4rwh4m6lpcf8wr0nps";
rev = "e2516e8cf4f2afb5185337073607eb9e84a61d2d";
};
}))
file
# gcc-wrapper
gdb
gnumake
gnutls
psmisc
# tlspool
wireshark-cli
gnutls
however, i don't need bepasty-server binaries in the interactive environment but instead i need to override pkgs so the bepasty service will use it!

Answer 1

thanks to lassulus!
here is what works now:
nixpkgs.config.packageOverrides = super: {
pythonPackages = super.pythonPackages // { bepasty-server = super.python27Packages.bepasty-server.overrideAttrs (oldAttrs: {
src = pkgs.fetchgit {
url = "https://github.com/bepasty/bepasty-server";
sha256 = "9ziqshmsf0rjvdhhca55sm0x8jz76fsf2q4rwh4m6lpcf8wr0nps";
#sha256 = "5ziqshmsf0rjvdhhca55sm0x8jz76fsf2q4rwh4m6lpcf8wr0nps";
#sha256 = "7ziqshmsf0rjvdhhca55sm0x8jz76fsf2q4rwh4m6lpcf8wr0nps";
rev = "e2516e8cf4f2afb5185337073607eb9e84a61d2d";
};
});
};
};