nixos/kapacitor: new service

nixos/modules/misc/ids.nix

@@ -332,6 +332,7 @@
       lirc = 305;
       lidarr = 306;
       slurm = 307;
+      kapacitor = 308;
 
       # When adding a uid, make sure it doesn't match an existing gid. And don't use uids above 399!
 
@@ -624,6 +625,7 @@
       lirc = 305;
       lidarr = 306;
       slurm = 307;
+      kapacitor = 308;
 
       # When adding a gid, make sure it doesn't match an existing
       # uid. Users and groups with the same name should have equal

nixos/modules/module-list.nix

@@ -433,6 +433,7 @@
   ./services/monitoring/hdaps.nix
   ./services/monitoring/heapster.nix
   ./services/monitoring/incron.nix
+  ./services/monitoring/kapacitor.nix
   ./services/monitoring/longview.nix
   ./services/monitoring/monit.nix
   ./services/monitoring/munin.nix

nixos/modules/services/monitoring/kapacitor.nix

@@ -0,0 +1,154 @@
+{ options, config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.kapacitor;
+
+  kapacitorConf = pkgs.writeTextFile {
+    name = "kapacitord.conf";
+    text = ''
+      hostname="${config.networking.hostName}"
+      data_dir="${cfg.dataDir}"
+
+      [http]
+        bind-address = "${cfg.bind}:${toString cfg.port}"
+        log-enabled = false
+        auth-enabled = false
+
+      [task]
+        dir = "${cfg.dataDir}/tasks"
+        snapshot-interval = "${cfg.taskSnapshotInterval}"
+
+      [replay]
+        dir = "${cfg.dataDir}/replay"
+
+      [storage]
+        boltdb = "${cfg.dataDir}/kapacitor.db"
+
+      ${optionalString (cfg.loadDirectory != null) ''
+        [load]
+          enabled = true
+          dir = "${cfg.loadDirectory}"
+      ''}
+
+      ${optionalString (cfg.defaultDatabase.enable) ''
+        [[influxdb]]
+          name = "default"
+          enabled = true
+          default = true
+          urls = [ "${cfg.defaultDatabase.url}" ]
+          username = "${cfg.defaultDatabase.username}"
+          password = "${cfg.defaultDatabase.password}"
+      ''}
+
+      ${cfg.extraConfig}
+    '';
+  };
+in
+{
+  options.services.kapacitor = {
+    enable = mkEnableOption "kapacitor";
+
+    dataDir = mkOption {
+      type = types.path;
+      example = "/var/lib/kapacitor";
+      default = "/var/lib/kapacitor";
+      description = "Location where Kapacitor stores its state";
+    };
+
+    port = mkOption {
+      type = types.int;
+      default = 9092;
+      description = "Port of Kapacitor";
+    };
+
+    bind = mkOption {
+      type = types.str;
+      default = "";
+      example = literalExample "0.0.0.0";
+      description = "Address to bind to. The default is to bind to all addresses";
+    };
+
+    extraConfig = mkOption {
+      description = "These lines go into kapacitord.conf verbatim.";
+      default = "";
+      type = types.lines;
+    };
+
+    user = mkOption {
+      type = types.str;
+      default = "kapacitor";
+      description = "User account under which Kapacitor runs";
+    };
+
+    group = mkOption {
+      type = types.str;
+      default = "kapacitor";
+      description = "Group under which Kapacitor runs";
+    };
+
+    taskSnapshotInterval = mkOption {
+      type = types.str;
+      description = "Specifies how often to snapshot the task state  (in InfluxDB time units)";
+      default = "1m0s";
+      example = "1m0s";
+    };
+
+    loadDirectory = mkOption {
+      type = types.nullOr types.path;
+      description = "Directory where to load services from, such as tasks, templates and handlers (or null to disable service loading on startup)";
+      default = null;
+    };
+
+    defaultDatabase = {
+      enable = mkEnableOption "kapacitor.defaultDatabase";
+
+      url = mkOption {
+        description = "The URL to an InfluxDB server that serves as the default database";
+        example = "http://localhost:8086";
+        type = types.string;
+      };
+
+      username = mkOption {
+        description = "The username to connect to the remote InfluxDB server";
+        type = types.string;
+      };
+
+      password = mkOption {
+        description = "The password to connect to the remote InfluxDB server";
+        type = types.string;
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ pkgs.kapacitor ];
+
+    systemd.services.kapacitor = {
+      description = "Kapacitor Real-Time Stream Processing Engine";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "networking.target" ];
+      serviceConfig = {
+        ExecStart = "${pkgs.kapacitor}/bin/kapacitord -config ${kapacitorConf}";
+        User = "kapacitor";
+        Group = "kapacitor";
+        PermissionsStartOnly = true;
+      };
+      preStart = ''
+        mkdir -p ${cfg.dataDir}
+        chown ${cfg.user}:${cfg.group} ${cfg.dataDir}
+      '';
+    };
+
+    users.users.kapacitor = {
+      uid = config.ids.uids.kapacitor;
+      description = "Kapacitor user";
+      home = cfg.dataDir;
+    };
+
+    users.groups.kapacitor = {
+      gid = config.ids.gids.kapacitor;
+    };
+  };
+}