Add cln feeadjuster plugin

modules/clightning-plugins/default.nix

@@ -14,6 +14,7 @@ in {
   imports = [
     ./clboss.nix
     ./commando.nix
+    ./feeadjuster.nix
     ./prometheus.nix
     ./summary.nix
     ./zmq.nix

modules/clightning-plugins/feeadjuster.nix

@@ -0,0 +1,78 @@
+{ config, lib, ... }:
+
+with lib;
+let
+  options.services.clightning.plugins.feeadjuster = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Enable feeaduster (clightning plugin).
+        This plugin auto-updates channel fees to keep channels balanced.
+
+        See here for for all available options:
+        https://github.com/lightningd/plugins/blob/master/feeadjuster/feeadjuster.py
+        Extra options can be set via `services.clightning.extraConfig`.
+      '';
+    };
+    fuzz = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Enable update threshold randomization and hysteresis.";
+    };
+    adjustOnForward = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Automatically update fees on forward events.";
+    };
+    method = mkOption {
+      type = types.enum [ "soft" "default" "hard" ];
+      default = "default";
+      description = ''
+        Adjustment method to calculate channel fees.
+        `soft`: less difference when adjusting fees.
+        `hard`: greater difference when adjusting fees.
+      '';
+    };
+    adjustDaily = mkOption {
+      type = types.bool;
+      default = true;
+      description = "Automatically update fees daily.";
+    };
+  };
+
+  cfg = config.services.clightning.plugins.feeadjuster;
+  inherit (config.services) clightning;
+in
+{
+  inherit options;
+
+  config = mkIf (cfg.enable && clightning.enable) {
+    services.clightning.extraConfig = ''
+      plugin=${config.nix-bitcoin.pkgs.clightning-plugins.feeadjuster.path}
+      feeadjuster-adjustment-method="${cfg.method}"
+    '' + optionalString (!cfg.fuzz) ''
+      feeadjuster-deactivate-fuzz
+    '' + optionalString (!cfg.adjustOnForward) ''
+      feeadjuster-deactivate-fee-update
+    '';
+
+    systemd = mkIf cfg.adjustDaily {
+      services.clightning-feeadjuster = {
+        # Only run when clightning is running
+        requisite = [ "clightning.service" ];
+        after = [ "clightning.service" ];
+        serviceConfig = {
+          Type = "oneshot";
+          User = "clightning";
+          ExecStart = "${clightning.package}/bin/lightning-cli --lightning-dir ${clightning.dataDir} feeadjust";
+        };
+        unitConfig.JoinsNamespaceOf = [ "clightning.service" ];
+        startAt = [ "daily" ];
+      };
+      timers.clightning-feeadjuster.timerConfig = {
+        RandomizedDelaySec = "6h";
+      };
+    };
+  };
+}

pkgs/clightning-plugins/default.nix

@@ -39,6 +39,9 @@ let
       scriptName = "cl-zmq";
       extraPkgs = [ twisted txzmq ];
     };
+    feeadjuster = {
+      description = "Dynamically changes channel fees to keep your channels more balanced";
+    };
   };
 
   basePkgs = [ nbPython3Packages.pyln-client ];