a rough prototype for running coder.com as a nixos system service

README.md

background

1. Now that coder is in nixpkgs at https://search.nixos.org/packages?channel=22.11&show=coder&from=0&size=50&sort=relevance&type=packages&query=coder
2. The next step is to enable running coder in NixOS via services.coder.enable = true;
3. Thus design configuration options such as https://search.nixos.org/options?channel=22.11&show=services.znc.user&from=0&size=50&sort=relevance&type=packages&query=znc
4. Refer to https://github.com/NixOS/nixpkgs/blob/nixos-22.11/nixos/modules/services/networking/znc/default.nix for an example of what is to be achieved.

next steps

1. What configuration options should we expose vs encouraging usage of extraFlags?
2. Is systemd configuration appropriate?
3. Are we happy with stateDir location?
4. Forcing accessUrl means Tunnel won't work but I don't think we want to encourage tunnel for systemd scenarios?

coder-service.nix

{ config, lib, pkgs, ... }:

with lib;

let

  inherit (pkgs) coder;

  cfg = config.services.coder;

  stateDir = "/var/lib/coder";

  coderFlags = [ "--global-config" "${stateDir}" "--access-url" "${accessUrl}" "--address" "${address}" ] ++ cfg.extraFlags;

in

{

  ###### interface

  options = {

    services.coder = {

      enable = mkOption {
        type = types.bool;
        default = false;
        description = lib.mdDoc ''
        '';
      };

      address = mkOption {
        type = types.str;
        description = lib.mdDoc ''
          Bind address of the server.
        '';
        example = literalExpression ''127.0.0.1:3000'';
        default = "127.0.0.1:3000";
      };


      accessUrl = mkOption {
        type = types.str;
        description = lib.mdDoc ''
          Set to the external URL that users and workspaces will use to
          connect to Coder. This must be accessible by all provisioned
          workspaces.
        '';
        example = literalExpression ''"https://coder.example.com"'';
        default = [];
      };


      extraFlags = mkOption {
        type = types.listOf types.str;
        description = lib.mdDoc "Extra flags passed to the coder command.";
        example = literalExpression ''[ "--experimental" ]'';
        default = [];
      };

    };

  };


  ###### implementation

  config = mkIf config.services.coder.enable {
    meta.maintainers = with lib.maintainers; [ ghuntley ];

    # Make tools such as coder available in the system path.
    environment.systemPackages = [ pkgs.coder ];

    users.users.coder =
      { isSystemUser = true;
        group = "coder";
        description = "Coder daemon user";
        home = stateDir;
      };
    users.groups.coder = {};

    systemd.services.coder =
      { description = "Coder Daemon";

        wantedBy = [ "multi-user.target" ];
        after = [ "network-online.target" ];

        preStart =
          ''
            mkdir -m 0755 -p ${stateDir}
            chown coder ${stateDir}
          '';

        serviceConfig = {
          ExecStart = "@${coder}/bin/coder coder server ${builtins.toString coderFlags}";
          Type = "forking";
        };
      };

  };
}