Heracles/flake.nix

{
  inputs = {
    nixpkgs.url = "nixpkgs";
    rust-overlay = {
      url = "github:oxalica/rust-overlay?ref=stable";
      inputs.nixpkgs.follows = "nixpkgs";
    };
    naersk.url = "github:nix-community/naersk";
    flake-compat = { url = github:edolstra/flake-compat; flake = false; };
    flake-utils.url = "github:numtide/flake-utils"; 
  };
  
  outputs = {nixpkgs, flake-utils, naersk, rust-overlay, ...}:
    flake-utils.lib.eachDefaultSystem (system: let
      overlays = [
        rust-overlay.overlays.default
      ];
      pkgs = import nixpkgs { inherit system overlays; };
      rust-bin = pkgs.rust-bin.stable."1.71.0".default;
      naersk-lib = pkgs.callPackage naersk {
          rustc = rust-bin;
          cargo = rust-bin;
      };
      heracles = naersk-lib.buildPackage {
          name = "heracles";
          verion = "0.0.1";
          src = ./.;
          nativeBuildInputs = [ pkgs.pkg-config ];
          buildInputs = (
            if pkgs.stdenv.isDarwin then
              with pkgs.darwin.apple_sdk.frameworks; [ Security SystemConfiguration ]
            else
            [ pkgs.openssl ]) ++ [rust-bin];
      };
    in
    {
      packages.default = heracles;
    }) // {
        nixosModule = {config, pkgs, lib}: with lib; {
            options = {
                services.heracles.enable = mkEnableOption "enable heracles service";
                services.heracles.listen = mkOption {
                    description = "[host]:port address for heracles to listen on";
                    default = "localhost:8080";
                    defaultText = "localhost:8080";
                };

                services.heracles.settings = mkOption {
                    description = "heracles dashboard Configuration";
                    default = [
                        {
                            title = "A dashboard";
                            graphs = [
                                {
                                    title = "Graph title";
                                    query_type = "Range";
                                    # yaxis formatting default for this graph
                                    d3_tick_format = "~s";
                                    plots = [
                                        {
                                            source = "http://heimdall:9001";
                                            query = ''
                                                sum by (instance)(irate(node_cpu_seconds_total{job="nodestats"}[5m]))
                                            '';
                                            meta = {
                                                name_label = "instance";
                                                name_prefix = "trace name prefix";
                                                name_suffix = "trace name suffix";
                                                named_axis = "y";
                                                # yaxis formatting for this subplot
                                                d3_tick_format = "~s";
                                            };
                                        }
                                    ];
                                    # span for this graph.
                                    span = {
                                        end = "now";
                                        duration = "1d";
                                        step_duration = "10min";
                                    };
                                }
                            ];
                            # default span for dashboard
                            span = {
                                end = "now";
                                duration = "1d";
                                step_duration = "10min";
                            };
                        }
                    ];
                    defaultText = ''
                    [
                        {
                            title = "A dashboard";
                            graphs = [
                                {
                                    title = "Graph title";
                                    query_type = "Range";
                                    # yaxis formatting default for this graph
                                    d3_tick_format = "~s";
                                    plots = [
                                        {
                                            source = "http://heimdall:9001";
                                            query = \'\'
                                                sum by (instance)(irate(node_cpu_seconds_total{job="nodestats"}[5m]))
                                            \'\';
                                            meta = {
                                                name_label = "instance";
                                                name_prefix = "trace name prefix";
                                                name_suffix = "trace name suffix";
                                                named_axis = "y";
                                                # yaxis formatting for this subplot
                                                d3_tick_format = "~s";
                                            };
                                        }
                                    ];
                                    # span for this graph.
                                    span = {
                                        end = "now";
                                        duration = "1d";
                                        step_duration = "10min";
                                    };
                                }
                            ];
                            # default span for dashboard
                            span = {
                                end = "now";
                                duration = "1d";
                                step_duration = "10min";
                            };
                        }
                    ]
                    '';
                };
            };

            config = mkIf config.services.heracles.enable {
                environment.etc."heracles.yaml" = {
                    text = (generators.toYAML {} config.services.heracles.settings);
                };
                systemd.services.heracles = {
                    wantedBy = [ "multi-user.target" "default.target" ];
                    wants = [ "network.target" ];
                    after = [ "network-online.target" ];
                    serviceConfig = {
                        Restart = "on-failure";
                        RestartSec = "30s";
                        ExecStart = "${pkgs.heracles}/bin/heracles --listen ${config.services.heracles.listen} --config=${config.environment.etc."heracles.yaml".target}";
                    };
                };
            };
        };
    };
}