Merge fort-nix/nix-bitcoin#487: Add feeadjust core lightning plugin

f9315db52c clightning/feeadjuster: add test (Erik Arvstedt)
1054e9a3b1 Add cln feeadjuster plugin (elsirion)

Pull request description:

ACKs for top commit:
  erikarvstedt:
    ACK f9315db52c
  jonasnick:
    ACK f9315db52c

Tree-SHA512: 878b5c2455d71cfd8503774f3f29fc36c7fc5337b583a850c4d944348e102a23de92aba6fadf4304cfd81a5684869f9c0b8cbe1673cf72b2b57f5846b2c73183

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 ];

test/tests.nix

@@ -134,6 +134,7 @@ let
     (mkIf config.test.features.clightningPlugins {
       services.clightning.plugins = {
         clboss.enable = true;
+        feeadjuster.enable = true;
         helpme.enable = true;
         monitor.enable = true;
         prometheus.enable = true;

test/tests.py

@@ -127,20 +127,24 @@ def _():
 def _():
     assert_running("clightning")
     assert_matches("runuser -u operator -- lightning-cli getinfo | jq", '"id"')
-    if test_data["clightning-plugins"]:
+
+    enabled_plugins = test_data["clightning-plugins"]
+    if enabled_plugins:
         plugin_list = succeed("lightning-cli plugin list")
         plugins = json.loads(plugin_list)["plugins"]
         active = set(plugin["name"] for plugin in plugins if plugin["active"])
-        failed = set(test_data["clightning-plugins"]).difference(active)
+        failed = set(enabled_plugins).difference(active)
         if failed:
             raise Exception(
                 f"The following clightning plugins are inactive:\n{failed}.\n\n"
                 f"Output of 'lightning-cli plugin list':\n{plugin_list}"
             )
-        else:
-            machine.log("Active clightning plugins:")
-            for p in test_data["clightning-plugins"]:
-                machine.log(os.path.basename(p))
+        active = [os.path.splitext(os.path.basename(p))[0] for p in enabled_plugins]
+        machine.log("\n".join(["Active clightning plugins:", *active]))
+
+        if "feeadjuster" in active:
+            # This is a one-shot service, so this command only succeeds if the service succeeds
+            succeed("systemctl start clightning-feeadjuster")
 
 @test("lnd")
 def _():