add support of nix

Closes #9

.envrc

@@ -0,0 +1 @@
+use flake

.github/workflows/build_nix.yml

@@ -0,0 +1,13 @@
+name: "Build legacy Nix package on Ubuntu"
+
+on:
+  push:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: cachix/install-nix-action@v12
+      - name: Building package
+        run: nix-build . -A defaultPackage.x86_64-linux

default.nix

@@ -0,0 +1,7 @@
+(import (
+  fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2"; }
+) {
+  src =  ./.;
+}).defaultNix

flake.lock

@@ -0,0 +1,77 @@
+{
+  "nodes": {
+    "naersk": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1655042882,
+        "narHash": "sha256-9BX8Fuez5YJlN7cdPO63InoyBy7dm3VlJkkmTt6fS1A=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "cddffb5aa211f50c4b8750adbec0bbbdfb26bb9f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "master",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1659190188,
+        "narHash": "sha256-LudYrDFPFaQMW0l68TYkPWRPKmqpxIFU1nWfylIp9AQ=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a3fddd46a7f3418d7e3940ded94701aba569161d",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "type": "indirect"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1659190188,
+        "narHash": "sha256-LudYrDFPFaQMW0l68TYkPWRPKmqpxIFU1nWfylIp9AQ=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "a3fddd46a7f3418d7e3940ded94701aba569161d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "naersk": "naersk",
+        "nixpkgs": "nixpkgs_2",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1656928814,
+        "narHash": "sha256-RIFfgBuKz6Hp89yRr7+NR5tzIAbn52h8vT6vXkYjZoM=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "7e2a3b3dfd9af950a856d66b0a7d01e3c18aa249",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,46 @@
+{
+  inputs = {
+    naersk.url = "github:nix-community/naersk/master";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, utils, naersk }:
+    utils.lib.eachDefaultSystem (system:
+      let
+        name = "vnetod";
+        pkgs = import nixpkgs { inherit system; };
+        naersk-lib = pkgs.callPackage naersk { };
+      in
+      rec {
+        # Executes by `nix build .#<name>`
+        packages = {
+         ${name} = naersk.lib.${system}.buildPackage {
+            pname = name;
+            root = ./.;
+          };
+        };
+        # Executes by `nix build .`
+        packages.default = packages.${name};
+        # the same but deprecated in Nix 2.7
+        defaultPackage = packages.default;
+
+        # Executes by `nix run .#<name> -- <args?>` 
+        apps = {
+          ${name} = utils.lib.mkApp {
+            inherit name;
+            drv = packages.${name};
+          };
+        };
+        # Executes by `nix run . -- <args?>`
+        apps.default = apps.${name};
+        # the same but deprecated in Nix 2.7
+        defaultApp = apps.default;
+
+        # Used by `nix develop`
+        devShell = with pkgs; mkShell {
+          buildInputs = [ cargo rustc rustfmt pre-commit rustPackages.clippy ];
+          RUST_SRC_PATH = rustPlatform.rustLibSrc;
+        };
+      });
+}

shell.nix

@@ -0,0 +1,7 @@
+(import (
+  fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2"; }
+) {
+  src =  ./.;
+}).shellNix