Merge pull request #179 from ralexstokes/optional-nixos-module

refactor nixos module into "submodules" per component

flake.nix

@@ -41,14 +41,5 @@
       devShells.x86_64-darwin.default = import ./shell.nix { pkgs = pkgs-for-system "x86_64-darwin"; };
       devShells.aarch64-darwin.default = import ./shell.nix { pkgs = pkgs-for-system "aarch64-darwin"; };
       devShells.x86_64-linux.default = import ./shell.nix { pkgs = pkgs-for-system "x86_64-linux"; };
-
-      # exercise defined modules in a "test machine"
-      nixosConfigurations.test = nixpkgs.lib.nixosSystem {
-        system = "x86_64-linux";
-        modules = [
-          ./nix/module-test.nix
-          self.nixosModules.mev-rs
-        ];
-      };
     };
 }

nix/module-test.nix

@@ -1,8 +1,10 @@
+# NOTE: currently doesn't do what we want...
 {
   services.mev-rs = {
-    enable = "build";
-    config-file = "example.config.toml";
-    features = "build,config";
+    build = {
+      config-file = "example.config.toml";
+      additional-features = [ "config" ];
+    };
   };
 
   boot.isContainer = true;

nix/module.nix

@@ -1,66 +1,83 @@
 pkg:
 { config, lib, pkgs, ... }:
 let
-  cfg = config.services.mev-rs;
-
-  component = cfg.enable;
-  # ensure the intended component is part of the feature set
-  features = if lib.strings.hasInfix component cfg.features then cfg.features else lib.strings.removePrefix "," "${cfg.features},${component}";
-
-  mev-rs = pkg.mev-rs {
+  mev-rs-with-features = features: pkg.mev-rs {
     inherit features;
     system = pkgs.system;
   };
 
-  name = "mev-${cfg.enable}-rs";
-
-  cmd = ''
-    ${mev-rs}/bin/mev \
-    ${component} \
-    ${cfg.config-file}
-  '';
-in
-{
-  options.services.mev-rs = {
-    enable = lib.mkOption {
-      type = lib.types.enum [ "boost" "build" ];
-      description = "which subcommand of `mev-rs` to run";
-    };
-    config-file = lib.mkOption {
-      type = lib.types.str;
-      description = ''
-        path to a config file suitable for the `mev-rs` toolkit
-      '';
-    };
-    features = lib.mkOption {
-      type = lib.types.str;
-      default = cfg.enable;
-      description = ''
-        feature set (comma-separated) to enable for `cargo` build
+  mev-rs-submodule = for-component: { config, ... }: with lib; with types;
+    let
+      features = strings.concatStringsSep "," [ for-component ] ++ config.additional-features;
+      mev-rs = mev-rs-with-features features;
+      name = "mev-${for-component}-rs";
+      cmd = ''
+        ${mev-rs}/bin/mev \
+        ${for-component} \
+        ${config.config-file}
       '';
-    };
-  };
-
-  config = {
-    networking.firewall = lib.mkIf (component == "build") {
-      allowedTCPPorts = [ 30303 ];
-      allowedUDPPorts = [ 30303 ];
-    };
-
-    environment.systemPackages = [
-      mev-rs
-    ];
+    in
+    {
+      options = {
+        component = mkOption {
+          type = enum [ "boost" "relay" "build" ];
+          default = for-component;
+        };
+        config-file = mkOption {
+          type = str;
+          description = ''
+            path to a config file suitable for the `mev-rs` toolkit
+          '';
+        };
+        additional-features = mkOption {
+          type = listOf str;
+          description = ''
+            additional Cargo features to include alongside those required for the `component`
+          '';
+        };
+        after-systemd-service = mkOption {
+          type = str;
+          default = "vc.service";
+          description = ''
+            the name of a systemd service to wait activation of before activating this unit
+          '';
+        };
+      };
+      config = {
+        environment.systemPackages = [
+          mev-rs
+        ];
+        networking.firewall = lib.mkIf (for-component == "build") {
+          allowedTCPPorts = [ 30303 ];
+          allowedUDPPorts = [ 30303 ];
+        };
 
-    systemd.services."${name}" = {
-      description = name;
-      wantedBy = [ "multi-user.target" ];
-      after = [ "vc.service" ];
-      serviceConfig = {
-        ExecStart = cmd;
-        Restart = "on-failure";
-        RestartSec = "10s";
-        SyslogIdentifier = name;
+        systemd.services."${name}" = {
+          description = name;
+          wantedBy = [ "multi-user.target" ];
+          after = [ config.after-systemd-service ];
+          serviceConfig = {
+            ExecStart = cmd;
+            Restart = "on-failure";
+            RestartSec = "10s";
+            SyslogIdentifier = for-component;
+          };
+        };
       };
     };
+in
+{
+  options.services.mev-rs = with lib; with types; mkOption {
+    type = listOf (submodule {
+      options.boost = mkOption {
+        type = attrsOf (submodule mev-rs-submodule "boost");
+      };
+      options.relay = mkOption {
+        type = attrsOf (submodule mev-rs-submodule "relay");
+      };
+      options.build = mkOption {
+        type = attrsOf (submodule mev-rs-submodule "build");
+      };
+    });
   };
 }