nixos/mailhog: add setSendmail option (#339283)

maintainers/maintainer-list.nix

@@ -19566,6 +19566,12 @@
     githubId = 61306;
     name = "Rene Treffer";
   };
+  RTUnreal = {
+    email = "unreal+nixpkgs@rtinf.net";
+    github = "RTUnreal";
+    githubId = 22859658;
+    name = "RTUnreal";
+  };
   rubenhoenle = {
     email = "git@hoenle.xyz";
     github = "rubenhoenle";

nixos/modules/services/mail/mailhog.nix

@@ -1,4 +1,9 @@
-{ config, lib, pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 let
   cfg = config.services.mailhog;
 
@@ -8,17 +13,24 @@ let
       "-smtp-bind-addr :${toString cfg.smtpPort}"
       "-ui-bind-addr :${toString cfg.uiPort}"
       "-storage ${cfg.storage}"
-    ] ++ lib.optional (cfg.storage == "maildir")
-      "-maildir-path $STATE_DIRECTORY"
+    ]
+    ++ lib.optional (cfg.storage == "maildir") "-maildir-path $STATE_DIRECTORY"
     ++ cfg.extraArgs
   );
 
+  mhsendmail = pkgs.writeShellScriptBin "mailhog-sendmail" ''
+    exec ${lib.getExe pkgs.mailhog} sendmail $@
+  '';
 in
 {
   ###### interface
 
   imports = [
-    (lib.mkRemovedOptionModule [ "services" "mailhog" "user" ] "")
+    (lib.mkRemovedOptionModule [
+      "services"
+      "mailhog"
+      "user"
+    ] "")
   ];
 
   options = {
@@ -26,8 +38,15 @@ in
     services.mailhog = {
       enable = lib.mkEnableOption "MailHog, web and API based SMTP testing";
 
+      setSendmail = lib.mkEnableOption "set the system sendmail to mailhogs's" // {
+        default = true;
+      };
+
       storage = lib.mkOption {
-        type = lib.types.enum [ "maildir" "memory" ];
+        type = lib.types.enum [
+          "maildir"
+          "memory"
+        ];
         default = "memory";
         description = "Store mails on disk or in memory.";
       };
@@ -52,13 +71,12 @@ in
 
       extraArgs = lib.mkOption {
         type = lib.types.listOf lib.types.str;
-        default = [];
+        default = [ ];
         description = "List of additional arguments to pass to the MailHog process.";
       };
     };
   };
 
-
   ###### implementation
 
   config = lib.mkIf cfg.enable {
@@ -69,11 +87,21 @@ in
       wantedBy = [ "multi-user.target" ];
       serviceConfig = {
         Type = "exec";
-        ExecStart = "${pkgs.mailhog}/bin/MailHog ${args}";
+        ExecStart = "${lib.getExe pkgs.mailhog} ${args}";
         DynamicUser = true;
         Restart = "on-failure";
         StateDirectory = "mailhog";
       };
     };
+
+    services.mail.sendmailSetuidWrapper = lib.mkIf cfg.setSendmail {
+      program = "sendmail";
+      source = lib.getExe mhsendmail;
+      # Communication happens through the network, no data is written to disk
+      owner = "nobody";
+      group = "nogroup";
+    };
   };
+
+  meta.maintainers = with lib.maintainers; [RTUnreal];
 }

nixos/tests/mailhog.nix

@@ -1,11 +1,9 @@
-import ./make-test-python.nix ({ lib, ... }: {
+import ./make-test-python.nix ({lib, ...}: {
   name = "mailhog";
-  meta.maintainers = with lib.maintainers; [ jojosch ];
+  meta.maintainers = with lib.maintainers; [jojosch RTUnreal];
 
-  nodes.machine = { pkgs, ... }: {
+  nodes.machine = {pkgs, ...}: {
     services.mailhog.enable = true;
-
-    environment.systemPackages = with pkgs; [ swaks ];
   };
 
   testScript = ''
@@ -14,11 +12,11 @@ import ./make-test-python.nix ({ lib, ... }: {
     machine.wait_for_unit("mailhog.service")
     machine.wait_for_open_port(1025)
     machine.wait_for_open_port(8025)
-    machine.succeed(
-        'echo "this is the body of the email" | swaks --to root@example.org --body - --server localhost:1025'
-    )
-    assert "this is the body of the email" in machine.succeed(
+    # Test sendmail wrapper (this uses smtp, which tests the connection)
+    machine.succeed('printf "To: root@example.com\r\n\r\nthis is the body of the email" | sendmail -t -i -f sender@example.com')
+    res = machine.succeed(
         "curl --fail http://localhost:8025/api/v2/messages"
     )
+    assert all(msg in res for msg in ["this is the body of the email", "sender@example.com", "root@example.com"])
   '';
 })