nix: add flake

flake.lock

@@ -0,0 +1,69 @@
+{
+  "nodes": {
+    "futils": {
+      "locked": {
+        "lastModified": 1644229661,
+        "narHash": "sha256-1YdnJAsNy69bpcjuoKdOYQX0YxZBiCYZo4Twxerqv7k=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "3cecb5b042f7f209c56ffd8371b2711a290ec797",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "ref": "master",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1646497237,
+        "narHash": "sha256-Ccpot1h/rV8MgcngDp5OrdmLTMaUTbStZTR5/sI7zW0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "062a0c5437b68f950b081bbfc8a699d57a4ee026",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-utils": [
+          "futils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1646153636,
+        "narHash": "sha256-AlWHMzK+xJ1mG267FdT8dCq/HvLCA6jwmx2ZUy5O8tY=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "b6bc0b21e1617e2b07d8205e7fae7224036dfa4b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "master",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "futils": "futils",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,102 @@
+{
+  description = "Kraken technical assessment";
+
+  inputs = {
+    futils = {
+      type = "github";
+      owner = "numtide";
+      repo = "flake-utils";
+      ref = "master";
+    };
+
+    nixpkgs = {
+      type = "github";
+      owner = "NixOS";
+      repo = "nixpkgs";
+      ref = "nixos-unstable";
+    };
+
+    pre-commit-hooks = {
+      type = "github";
+      owner = "cachix";
+      repo = "pre-commit-hooks.nix";
+      ref = "master";
+      inputs = {
+        flake-utils.follows = "futils";
+        nixpkgs.follows = "nixpkgs";
+      };
+    };
+  };
+
+  outputs = { self, futils, nixpkgs, pre-commit-hooks }:
+    {
+      overlay = final: prev: {
+        kraken = final.stdenv.mkDerivation {
+          pname = "kraken";
+          version = "0.0.0";
+
+          src = self;
+
+          nativeBuildInputs = with final; [
+            cmake
+            ninja
+            pkg-config
+          ];
+
+          checkInputs = with final; [
+            gtest
+          ];
+
+          doCheck = true;
+
+          meta = with final.lib; {
+            description = "Order book";
+            homepage = "https://gitea.belanyi.fr/ambroisie/kraken-assessment";
+            license = licenses.mit;
+            maintainers = [ ambroisie ];
+            platforms = platforms.unix;
+          };
+        };
+      };
+    } // futils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; overlays = [ self.overlay ]; };
+      in
+      {
+        checks = {
+          inherit (self.packages.${system}) kraken;
+
+          pre-commit = pre-commit-hooks.lib.${system}.run {
+            src = self;
+
+            hooks = {
+              nixpkgs-fmt = {
+                enable = true;
+              };
+
+              clang-format = {
+                enable = true;
+                name = "clang-format";
+                entry = "${pkgs.clang-tools}/bin/clang-format -style=file -i";
+                types = [ "text" "c++" ];
+                language = "system";
+              };
+            };
+          };
+        };
+
+        defaultPackage = self.packages.${system}.kraken;
+
+        devShell = pkgs.mkShell {
+          inputsFrom = with self.packages.${system}; [
+            kraken
+          ];
+
+          inherit (self.checks.${system}.pre-commit) shellHook;
+        };
+
+        packages = futils.lib.flattenTree {
+          inherit (pkgs) kraken;
+        };
+      });
+}