Merge pull request #7565 from offlinehacker/nixos/confd/module

nixos: add confd module

nixos/modules/module-list.nix

···
   ./services/misc/canto-daemon.nix
   ./services/misc/cpuminer-cryptonight.nix
   ./services/misc/cgminer.nix
+  ./services/misc/confd.nix
   ./services/misc/dictd.nix
   ./services/misc/disnix.nix
   ./services/misc/docker-registry.nix

nixos/modules/services/misc/confd.nix

···
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.confd;
+
+  confdConfig = ''
+    backend = "${cfg.backend}"
+    confdir = "${cfg.confDir}"
+    interval = ${toString cfg.interval}
+    nodes = [ ${concatMapStringsSep "," (s: ''"${s}"'') cfg.nodes}, ]
+    prefix = "${cfg.prefix}"
+    log-level = "${cfg.logLevel}"
+    watch = ${if cfg.watch then "true" else "false"}
+  '';
+
+in {
+  options.services.confd = {
+    enable = mkEnableOption "Whether to enable confd service.";
+
+    backend = mkOption {
+      description = "Confd config storage backend to use.";
+      default = "etcd";
+      type = types.enum ["etcd" "consul" "redis" "zookeeper"];
+    };
+
+    interval = mkOption {
+      description = "Confd check interval.";
+      default = 10;
+      type = types.int;
+    };
+
+    nodes = mkOption {
+      description = "Confd list of nodes to connect to.";
+      default = [ "http://127.0.0.1:4001" ];
+      type = types.listOf types.str;
+    };
+
+    watch = mkOption {
+      description = "Confd, whether to watch etcd config for changes.";
+      default = true;
+      type = types.bool;
+    };
+
+    prefix = mkOption {
+      description = "The string to prefix to keys.";
+      default = "/";
+      type = types.path;
+    };
+
+    logLevel = mkOption {
+      description = "Confd log level.";
+      default = "info";
+      type = types.enum ["info" "debug"];
+    };
+
+    confDir = mkOption {
+      description = "The path to the confd configs.";
+      default = "/etc/confd";
+      type = types.path;
+    };
+
+    package = mkOption {
+      description = "Confd package to use.";
+      default = pkgs.goPackages.confd;
+      type = types.package;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.confd = {
+      description = "Confd Service.";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        ExecStart = "${cfg.package}/bin/confd";
+      };
+    };
+
+    environment.etc = {
+      "confd/confd.toml".text = confdConfig;
+    };
+
+    environment.systemPackages = [ cfg.package ];
+
+    services.etcd.enable = mkIf (cfg.backend == "etcd") (mkDefault true);
+  };
+}