mailman: init package for Mailman CLI

We already had python3Packages.mailman, but that's only really usable
as a library.  The only other option was to create a whole Python
environment, which was undesirable to install as a system-wide
package.

nixos/modules/services/mail/mailman.nix

@@ -6,19 +6,6 @@ let
 
   cfg = config.services.mailman;
 
-  mailmanPyEnv = pkgs.python3.withPackages (ps: with ps; [mailman mailman-hyperkitty]);
-
-  mailmanExe = with pkgs; stdenv.mkDerivation {
-    name = "mailman-" + python3Packages.mailman.version;
-    buildInputs = [makeWrapper];
-    unpackPhase = ":";
-    installPhase = ''
-      mkdir -p $out/bin
-      makeWrapper ${mailmanPyEnv}/bin/mailman $out/bin/mailman \
-        --set MAILMAN_CONFIG_FILE /etc/mailman.cfg
-   '';
-  };
-
   mailmanWeb = pkgs.python3Packages.mailman-web.override {
     serverEMail = cfg.siteOwner;
     archiverKey = cfg.hyperkittyApiKey;
@@ -189,7 +176,7 @@ in {
     users.users.mailman = { description = "GNU Mailman"; isSystemUser = true; };
 
     environment = {
-      systemPackages = [ mailmanExe mailmanWebExe pkgs.sassc ];
+      systemPackages = [ pkgs.mailman mailmanWebExe pkgs.sassc ];
       etc."mailman.cfg".text = mailmanCfg;
     };
 
@@ -205,8 +192,8 @@ in {
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
       serviceConfig = {
-        ExecStart = "${mailmanExe}/bin/mailman start";
-        ExecStop = "${mailmanExe}/bin/mailman stop";
+        ExecStart = "${pkgs.mailman}/bin/mailman start";
+        ExecStop = "${pkgs.mailman}/bin/mailman stop";
         User = "mailman";
         Type = "forking";
         RuntimeDirectory = "mailman";
@@ -271,7 +258,7 @@ in {
       description = "Trigger daily Mailman events";
       startAt = "daily";
       serviceConfig = {
-        ExecStart = "${mailmanExe}/bin/mailman digests --send";
+        ExecStart = "${pkgs.mailman}/bin/mailman digests --send";
         User = "mailman";
       };
     };

pkgs/servers/mail/mailman/default.nix

@@ -28,15 +28,12 @@ buildPythonPackage rec {
   '';
 
   # Mailman assumes that those scripts in $out/bin are Python scripts. Wrapping
-  # them in shell code breaks this assumption. The proper way to use mailman is
-  # to create a specialized python interpreter:
-  #
-  #   python37.withPackages (ps: [ps.mailman])
+  # them in shell code breaks this assumption. Use the wrapped version (see
+  # wrapped.nix) if you need the CLI (rather than the Python library).
   #
   # This gives a properly wrapped 'mailman' command plus an interpreter that
   # has all the necessary search paths to execute unwrapped 'master' and
-  # 'runner' scripts. The setup is a little tricky, but fortunately NixOS is
-  # about to get a OS module that takes care of those details.
+  # 'runner' scripts.
   dontWrapPythonPrograms = true;
 
   meta = {

pkgs/servers/mail/mailman/wrapped.nix

@@ -0,0 +1,20 @@
+{ runCommand, lib, makeWrapper, python3
+, archivers ? [ python3.pkgs.mailman-hyperkitty ]
+}:
+
+let
+  inherit (python3.pkgs) makePythonPath mailman;
+in
+
+runCommand "${mailman.name}-wrapped" {
+  inherit (mailman) meta;
+  buildInputs = [ makeWrapper ];
+  passthru = mailman.passthru // { unwrapped = mailman; };
+} ''
+  mkdir -p "$out/bin"
+  cd "${mailman}/bin"
+  for exe in *; do
+    makeWrapper "${mailman}/bin/$exe" "$out/bin/$exe" \
+        --set PYTHONPATH ${makePythonPath ([ mailman ] ++ archivers)}
+  done
+''

pkgs/top-level/all-packages.nix

@@ -15321,6 +15321,8 @@ in
 
   labelImg = callPackage ../applications/science/machine-learning/labelimg { };
 
+  mailman = callPackage ../servers/mail/mailman/wrapped.nix { };
+
   mailman-rss = callPackage ../development/python-modules/mailman-rss { };
 
   mattermost = callPackage ../servers/mattermost { };