Add nix shell and some checks

flake.nix

@@ -1,16 +1,119 @@
 {
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-
+    devshell.url = "github:numtide/devshell";
     flake-utils.url = "github:numtide/flake-utils";
+    nix-filter.url = "github:numtide/nix-filter";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
   };
 
-  outputs = { self, nixpkgs, flake-utils }: {
-    serviceConfig = self.lib.makeServiceConfig {
-      system = flake-utils.lib.system.x86_64-linux;
-      module = { imports = [ ./nix/modules ]; };
-    };
+  outputs =
+    { self
+    , nixpkgs
+    , flake-utils
+    , nix-filter
+    , rust-overlay
+    , devshell
+    , treefmt-nix
+    , pre-commit-hooks
+    ,
+    }:
+    flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs {
+        inherit system;
+        overlays = [ (import rust-overlay) devshell.overlay ];
+      };
+      rust = pkgs.rust-bin.stable."1.64.0";
+      llvm = pkgs.llvmPackages_latest;
+      # treefmt-nix configuration
+      treefmt.config = {
+        projectRootFile = "flake.nix";
+        programs = {
+          nixpkgs-fmt.enable = true;
+          rustfmt = {
+            enable = true;
+            package = rust.rustfmt;
+          };
+        };
+      };
+    in
+    rec {
+      serviceConfig = lib.makeServiceConfig {
+        inherit system;
+        module = { imports = [ ./nix/modules ]; };
+      };
 
-    lib = import ./nix/lib.nix { inherit nixpkgs; };
-  };
+      lib = import ./nix/lib.nix { inherit nixpkgs; };
+
+      packages = rec {
+        service-manager =
+          pkgs.rustPlatform.buildRustPackage
+            {
+              pname = "service-manager";
+              version = (pkgs.lib.importTOML ./Cargo.toml).package.version;
+
+              src = nix-filter.lib {
+                root = ./.;
+                include = [ "Cargo.toml" "Cargo.lock" (nix-filter.lib.inDirectory "src") ];
+              };
+
+              cargoLock.lockFile = ./Cargo.lock;
+            };
+        default = service-manager;
+      };
+      devShells.default = pkgs.devshell.mkShell {
+        packages = with pkgs; [
+          llvm.clang
+          openssl
+          pkg-config
+          rust.default
+          (treefmt-nix.lib.mkWrapper pkgs treefmt.config)
+        ];
+        env = [
+          {
+            name = "LIBCLANG_PATH";
+            value = "${llvm.libclang}/lib";
+          }
+          {
+            # for rust-anaylzer
+            name = "RUST_SRC_PATH";
+            value = "${rust.rust-src}";
+          }
+          {
+            name = "RUST_BACKTRACE";
+            value = "1";
+          }
+          {
+            name = "RUST_LOG";
+            value = "info";
+          }
+          {
+            name = "DEVSHELL_NO_MOTD";
+            value = "1";
+          }
+        ];
+        devshell.startup.pre-commit.text = self.checks.${system}.pre-commit-check.shellHook;
+      };
+      checks = {
+        pre-commit-check = pre-commit-hooks.lib.${system}.run {
+          src = ./.;
+          hooks = {
+            check-format = {
+              enable = true;
+              entry = "treefmt --fail-on-change";
+            };
+            cargo-clippy = {
+              enable = true;
+              description = "Lint Rust code.";
+              entry = "cargo-clippy --workspace -- -D warnings";
+              files = "\\.rs$";
+              pass_filenames = false;
+            };
+          };
+        };
+      };
+    });
 }