flake.nix: create packaging, generate coverage

flake.nix

@@ -7,7 +7,9 @@
   };
 
   outputs = { self, nixpkgs, rust-overlay }@inputs:
-  let 
+  let
+    inherit (nixpkgs) lib;
+
     systems = [
       "x86_64-linux"
       "aarch64-linux"
@@ -15,6 +17,7 @@
       "aarch64-darwin"
       "armv7l-linux"
     ];
+
     forAllSystems = f: nixpkgs.lib.genAttrs systems (system: let
       pkgs = import nixpkgs {
         inherit system;
@@ -27,6 +30,16 @@
       toolchain = rust-bin.stable.latest.default;
     in f system pkgs toolchain);
   in {
+
+    apps = let
+      mkApp = program: { type = "app"; program = toString program; };
+    in forAllSystems (system: pkgs: _: {
+      mysqladm-rs = mkApp (lib.getExe self.packages.${system}.mysqladm-rs);
+      coverage = mkApp (pkgs.writeScript "mysqladm-rs-coverage" ''
+        ${lib.getExe pkgs.python3} -m http.server -d "${self.packages.${system}.coverage}/html/src"
+      '');
+    });
+
     devShell = forAllSystems (system: pkgs: toolchain: pkgs.mkShell {
       nativeBuildInputs = with pkgs; [
         toolchain
@@ -36,5 +49,33 @@
 
       RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
     });
+
+    overlays = {
+      default = self.overlays.mysqladm-rs;
+      greg-ng = final: prev: {
+        inherit (self.packages.${prev.system}) mysqladm-rs;
+      };
+    };
+
+    packages = let
+      cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+      cargoLock = ./Cargo.lock;
+      src = builtins.filterSource (path: type: let
+        baseName = baseNameOf (toString path);
+      in !(lib.any (b: b) [
+          (!(lib.cleanSourceFilter path type))
+          (baseName == "target" && type == "directory")
+          (baseName == "nix" && type == "directory")
+          (baseName == "flake.nix" && type == "regular")
+          (baseName == "flake.lock" && type == "regular")
+        ])) ./.;
+    in forAllSystems (system: pkgs: _: {
+      default = self.packages.${system}.mysqladm-rs;
+      mysqladm-rs = pkgs.callPackage ./nix/default.nix { inherit cargoToml cargoLock src; };
+      coverage = pkgs.callPackage ./nix/coverage.nix { inherit cargoToml cargoLock src; };
+      filteredSource = pkgs.runCommandLocal "filtered-source" { } ''
+        ln -s ${src} $out
+      '';
+    });
   };
 }