flake.nix: refactor as overlay

Author: balsoft

flake.nix

@@ -20,38 +20,25 @@
   };
 
   outputs = { self, nixpkgs, utils, naersk, ... }:
-    utils.lib.eachDefaultSystem (system:
-      let
-        pkgs = import nixpkgs { inherit system; };
-        naersk-lib = pkgs.callPackage naersk { };
-        isDarwin = pkgs.lib.strings.hasSuffix "-darwin" system;
-        darwinOptions = pkgs.lib.optionalAttrs isDarwin {
-          nativeBuildInputs = [
-            pkgs.darwin.apple_sdk.frameworks.SystemConfiguration
-          ];
-        };
-      in
-      {
-        defaultPackage = self.packages."${system}".deploy-rs;
-        packages.deploy-rs = naersk-lib.buildPackage (darwinOptions // {
+  {
+    overlay = final: prev:
+    let
+      naersk-lib = final.callPackage naersk { };
+      system = final.system;
+      isDarwin = final.lib.strings.hasSuffix "-darwin" system;
+      darwinOptions = final.lib.optionalAttrs isDarwin {
+        nativeBuildInputs = [
+          final.darwin.apple_sdk.frameworks.SystemConfiguration
+        ];
+      };
+    in
+    {
+      deploy-rs = {
+
+        deploy-rs = naersk-lib.buildPackage (darwinOptions // {
           root = ./.;
         });
 
-        defaultApp = self.apps."${system}".deploy-rs;
-        apps.deploy-rs = {
-          type = "app";
-          program = "${self.defaultPackage."${system}"}/bin/deploy";
-        };
-
-        devShell = pkgs.mkShell {
-          inputsFrom = [ self.packages.${system}.deploy-rs ];
-          buildInputs = [ pkgs.nixUnstable ];
-        };
-
-        checks = {
-          deploy-rs = self.defaultPackage.${system}.overrideAttrs (super: { doCheck = true; });
-        };
-
         lib = rec {
 
           setActivate = builtins.trace
@@ -62,31 +49,31 @@
             custom =
               {
                 __functor = customSelf: base: activate:
-                  pkgs.buildEnv {
+                  final.buildEnv {
                     name = ("activatable-" + base.name);
                     paths =
                       [
                         base
-                        (pkgs.writeTextFile {
+                        (final.writeTextFile {
                           name = base.name + "-activate-path";
                           text = ''
-                            #!${pkgs.runtimeShell}
+                            #!${final.runtimeShell}
                             set -euo pipefail
 
                             if [[ "''${DRY_ACTIVATE:-}" == "1" ]]
                             then
-                                ${customSelf.dryActivate or "echo ${pkgs.writeScript "activate" activate}"}
+                                ${customSelf.dryActivate or "echo ${final.writeScript "activate" activate}"}
                             else
                                 ${activate}
                             fi
                           '';
                           executable = true;
                           destination = "/deploy-rs-activate";
                         })
-                        (pkgs.writeTextFile {
+                        (final.writeTextFile {
                             name = base.name + "-activate-rs";
                             text = ''
-                            #!${pkgs.runtimeShell}
+                            #!${final.runtimeShell}
                             exec ${self.defaultPackage.${system}}/bin/activate "$@"
                           '';
                           executable = true;
@@ -104,7 +91,7 @@
 
               # https://github.com/serokell/deploy-rs/issues/31
               ${with base.config.boot.loader;
-              pkgs.lib.optionalString systemd-boot.enable
+              final.lib.optionalString systemd-boot.enable
               "sed -i '/^default /d' ${efi.efiSysMountPoint}/loader/loader.conf"}
             '';
 
@@ -114,15 +101,15 @@
           };
 
           deployChecks = deploy: builtins.mapAttrs (_: check: check deploy) {
-            schema = deploy: pkgs.runCommandNoCC "jsonschema-deploy-system" { } ''
-              ${pkgs.python3.pkgs.jsonschema}/bin/jsonschema -i ${pkgs.writeText "deploy.json" (builtins.toJSON deploy)} ${./interface.json} && touch $out
+            schema = deploy: final.runCommandNoCC "jsonschema-deploy-system" { } ''
+              ${final.python3.pkgs.jsonschema}/bin/jsonschema -i ${final.writeText "deploy.json" (builtins.toJSON deploy)} ${./interface.json} && touch $out
             '';
 
             activate = deploy:
               let
-                profiles = builtins.concatLists (pkgs.lib.mapAttrsToList (nodeName: node: pkgs.lib.mapAttrsToList (profileName: profile: [ (toString profile.path) nodeName profileName ]) node.profiles) deploy.nodes);
+                profiles = builtins.concatLists (final.lib.mapAttrsToList (nodeName: node: final.lib.mapAttrsToList (profileName: profile: [ (toString profile.path) nodeName profileName ]) node.profiles) deploy.nodes);
               in
-              pkgs.runCommandNoCC "deploy-rs-check-activate" { } ''
+              final.runCommandNoCC "deploy-rs-check-activate" { } ''
                 for x in ${builtins.concatStringsSep " " (map (p: builtins.concatStringsSep ":" p) profiles)}; do
                   profile_path=$(echo $x | cut -f1 -d:)
                   node_name=$(echo $x | cut -f2 -d:)
@@ -137,5 +124,32 @@
               '';
           };
         };
+      };
+    };
+  } //
+    utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; overlays = [ self.overlay ]; };
+      in
+      {
+        defaultPackage = self.packages."${system}".deploy-rs;
+        packages.deploy-rs = pkgs.deploy-rs.deploy-rs;
+
+        defaultApp = self.apps."${system}".deploy-rs;
+        apps.deploy-rs = {
+          type = "app";
+          program = "${self.defaultPackage."${system}"}/bin/deploy";
+        };
+
+        devShell = pkgs.mkShell {
+          inputsFrom = [ self.packages.${system}.deploy-rs ];
+          buildInputs = [ pkgs.nixUnstable ];
+        };
+
+        checks = {
+          deploy-rs = self.defaultPackage.${system}.overrideAttrs (super: { doCheck = true; });
+        };
+
+        lib = pkgs.deploy-rs.lib;
       });
 }