nixos/prometheus-restic-exporter: init module

nixos/modules/services/monitoring/prometheus/exporters.nix

@@ -71,6 +71,7 @@ let
     "pve"
     "py-air-control"
     "redis"
+    "restic"
     "rspamd"
     "rtl_433"
     "sabnzbd"

nixos/modules/services/monitoring/prometheus/exporters/restic.nix

@@ -0,0 +1,131 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.restic;
+in
+{
+  port = 9753;
+  extraOpts = {
+    repository = mkOption {
+      type = types.str;
+      description = lib.mdDoc ''
+        URI pointing to the repository to monitor.
+      '';
+      example = "sftp:[email protected]:/backups/example";
+    };
+
+    passwordFile = mkOption {
+      type = types.path;
+      description = lib.mdDoc ''
+        File containing the password to the repository.
+      '';
+      example = "/etc/nixos/restic-password";
+    };
+
+    environmentFile = mkOption {
+      type = with types; nullOr path;
+      default = null;
+      description = lib.mdDoc ''
+        File containing the credentials to access the repository, in the
+        format of an EnvironmentFile as described by systemd.exec(5)
+      '';
+    };
+
+    refreshInterval = mkOption {
+      type = types.ints.unsigned;
+      default = 60;
+      description = lib.mdDoc ''
+        Refresh interval for the metrics in seconds.
+        Computing the metrics is an expensive task, keep this value as high as possible.
+      '';
+    };
+
+    rcloneOptions = mkOption {
+      type = with types; attrsOf (oneOf [ str bool ]);
+      default = { };
+      description = lib.mdDoc ''
+        Options to pass to rclone to control its behavior.
+        See <https://rclone.org/docs/#options> for
+        available options. When specifying option names, strip the
+        leading `--`. To set a flag such as
+        `--drive-use-trash`, which does not take a value,
+        set the value to the Boolean `true`.
+      '';
+    };
+
+    rcloneConfig = mkOption {
+      type = with types; attrsOf (oneOf [ str bool ]);
+      default = { };
+      description = lib.mdDoc ''
+        Configuration for the rclone remote being used for backup.
+        See the remote's specific options under rclone's docs at
+        <https://rclone.org/docs/>. When specifying
+        option names, use the "config" name specified in the docs.
+        For example, to set `--b2-hard-delete` for a B2
+        remote, use `hard_delete = true` in the
+        attribute set.
+
+        ::: {.warning}
+        Secrets set in here will be world-readable in the Nix
+        store! Consider using the {option}`rcloneConfigFile`
+        option instead to specify secret values separately. Note that
+        options set here will override those set in the config file.
+        :::
+      '';
+    };
+
+    rcloneConfigFile = mkOption {
+      type = with types; nullOr path;
+      default = null;
+      description = lib.mdDoc ''
+        Path to the file containing rclone configuration. This file
+        must contain configuration for the remote specified in this backup
+        set and also must be readable by root.
+
+        ::: {.caution}
+        Options set in `rcloneConfig` will override those set in this
+        file.
+        :::
+      '';
+    };
+  };
+
+  serviceOpts = {
+    serviceConfig = {
+      ExecStart = ''
+        ${pkgs.prometheus-restic-exporter}/bin/restic-exporter.py \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+      EnvironmentFile = mkIf (cfg.environmentFile != null) cfg.environmentFile;
+    };
+    environment =
+      let
+        rcloneRemoteName = builtins.elemAt (splitString ":" cfg.repository) 1;
+        rcloneAttrToOpt = v: "RCLONE_" + toUpper (builtins.replaceStrings [ "-" ] [ "_" ] v);
+        rcloneAttrToConf = v: "RCLONE_CONFIG_" + toUpper (rcloneRemoteName + "_" + v);
+        toRcloneVal = v: if lib.isBool v then lib.boolToString v else v;
+      in
+      {
+        RESTIC_REPO_URL = cfg.repository;
+        RESTIC_REPO_PASSWORD_FILE = cfg.passwordFile;
+        LISTEN_ADDRESS = cfg.listenAddress;
+        LISTEN_PORT = toString cfg.port;
+        REFRESH_INTERVAL = toString cfg.refreshInterval;
+      }
+      // (mapAttrs'
+        (name: value:
+          nameValuePair (rcloneAttrToOpt name) (toRcloneVal value)
+        )
+        cfg.rcloneOptions)
+      // optionalAttrs (cfg.rcloneConfigFile != null) {
+        RCLONE_CONFIG = cfg.rcloneConfigFile;
+      }
+      // (mapAttrs'
+        (name: value:
+          nameValuePair (rcloneAttrToConf name) (toRcloneVal value)
+        )
+        cfg.rcloneConfig);
+  };
+}