add flake support

docs/setup-guide.rst

@@ -97,6 +97,34 @@ After a ``nixos-rebuild switch --upgrade`` your server should be good to
 go. If you want to use ``nixops`` to deploy the server, look in the
 subfolder ``nixops`` for some inspiration.
 
+If you're using `flakes <https://nixos.wiki/wiki/Flakes>`__, you can use
+the following minimal ``flake.nix`` as an example:
+
+.. code:: nix
+
+   {
+     description = "NixOS configuration";
+
+     inputs.simple-nixos-mailserver.url = "gitlab:simple-nixos-mailserver/nixos-mailserver";
+
+     outputs = { self, nixpkgs, simple-nixos-mailserver }: {
+       nixosConfigurations = {
+         hostname = nixpkgs.lib.nixosSystem {
+           system = "x86_64-linux";
+           modules = [
+             simple-nixos-mailserver.nixosModule
+             {
+               mailserver = {
+                 enable = true;
+                 # ...
+               };
+             }
+           ];
+         };
+       };
+     };
+   }
+
 B) Setup everything else
 ~~~~~~~~~~~~~~~~~~~~~~~~
 

flake.lock

@@ -0,0 +1,42 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1607522989,
+        "narHash": "sha256-o/jWhOSAlaK7y2M57OIriRt6whuVVocS/T0mG7fd1TI=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "e9158eca70ae59e73fae23be5d13d3fa0cfc78b4",
+        "type": "github"
+      },
+      "original": {
+        "id": "nixpkgs",
+        "ref": "nixos-unstable",
+        "type": "indirect"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "utils": "utils"
+      }
+    },
+    "utils": {
+      "locked": {
+        "lastModified": 1605370193,
+        "narHash": "sha256-YyMTf3URDL/otKdKgtoMChu4vfVL3vCMkRqpGifhUn0=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "5021eac20303a61fafe17224c087f5519baed54d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,26 @@
+{
+  description = "A complete and Simple Nixos Mailserver";
+
+  inputs = {
+    utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "flake:nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, utils, nixpkgs }: {
+    nixosModules.mailserver = import ./.;
+    nixosModule = self.nixosModules.mailserver;
+  } // utils.lib.eachDefaultSystem (system: let
+    pkgs = nixpkgs.legacyPackages.${system};
+  in {
+    devShell = pkgs.mkShell {
+      buildInputs = with pkgs; [
+        (python3.withPackages (p: with p; [
+          sphinx
+          sphinx_rtd_theme
+        ]))
+        jq
+        clamav
+      ];
+    };
+  });
+}

nixops/single-server.nix

@@ -5,7 +5,7 @@
     { config, pkgs, ... }:
     {
         imports = [
-            ./../default.nix
+            ../default.nix
         ];
 
         mailserver = {

shell.nix

@@ -1,11 +1 @@
-let
+(import (builtins.fetchGit "https://github.com/edolstra/flake-compat") { src = ./.; }).shellNix
-  nixpkgs = (import ./nix/sources.nix).nixpkgs-unstable;
-  pkgs = import nixpkgs {};
-in
-pkgs.mkShell {
-  buildInputs = with pkgs; [
-  (python3.withPackages(p: [p.sphinx p.sphinx_rtd_theme]))
-  niv
-  jq clamav
-  ];
-}