modules/pleroma.nix: handle configuration from the module.

co-authored-by: duponin <duponin@locahlo.st>

modules/pleroma.nix

@@ -23,10 +23,37 @@ in {
         default = "pleroma";
         description = "Group account under which pleroma runs.";
       };
+
+      configs = mkOption {
+        type = with types; listOf str;
+        description = "TODO";
+        default = ''
+        '';
+      };
+
+      secretConfigFile = mkOption {
+        type = types.str;
+        default = "/var/lib/pleroma/secrets.exs";
+        description = "Path to the file containing your secret pleroma configuration.";
+      };
     };
   };
 
   config = lib.mkIf cfg.enable {
+    assertions = [
+      {
+        assertion = (builtins.length cfg.configs) > 0;
+        message = ''
+          This is a brand new installation. In that case you can use
+          `pleroma_ctl instance gen --output config.exs --output-psql setup.psql`,
+          this will prompt you some questions and will generate both your
+          config file and database initial migration. Note: `pleroma_ctl`
+          will be in your system path as soon as you enable the pleroma
+          service. You can alternatively build it by building this repo's
+          `default.nix` derivation.
+        '';
+      }
+    ];
     users = {
       users."${cfg.user}" = {
         description = "Pleroma user";
@@ -38,6 +65,11 @@ in {
 
     environment.systemPackages = [ cfg.package ];
 
+    environment.etc."/pleroma/config.exs" = ''
+      ${lib.concatMapStrings (x: "${x}") cfg.configs} 
+      include "${cfg.secretConfigFile}"
+    '';
+
     systemd.services.pleroma = {
       description = "Pleroma social network";
       after = [ "network-online.target" "postgresql.service" ];