dovecot: Add spam filter traning using imapsieve

mail-server/dovecot.nix

@@ -27,6 +27,26 @@ let
   dovecotMaildir = "maildir:${cfg.mailDirectory}/%d/%n${maildirLayoutAppendix}";
 
   postfixCfg = config.services.postfix;
+  dovecot2Cfg = config.services.dovecot2;
+
+  stateDir = "/var/lib/dovecot";
+
+  pipeBin = pkgs.stdenv.mkDerivation {
+    name = "pipe_bin";
+    src = ./dovecot/pipe_bin;
+    buildInputs = with pkgs; [ makeWrapper coreutils bash rspamd ];
+    buildCommand = ''
+      mkdir -p $out/pipe/bin
+      cp $src/* $out/pipe/bin/
+      chmod a+x $out/pipe/bin/*
+      patchShebangs $out/pipe/bin
+
+      for file in $out/pipe/bin/*; do
+        wrapProgram $file \
+          --set PATH "${pkgs.coreutils}/bin:${pkgs.rspamd}/bin"
+      done
+    '';
+  };
 in
 {
   config = with cfg; lib.mkIf enable {
@@ -68,6 +88,7 @@ in
 
         protocol imap {
           mail_max_userip_connections = ${toString cfg.maxConnectionsPerUser}
+          mail_plugins = $mail_plugins imap_sieve
         }
 
         protocol pop3 {
@@ -118,14 +139,40 @@ in
         }
 
         plugin {
+          sieve_plugins = sieve_imapsieve sieve_extprograms
           sieve = file:/var/sieve/%u/scripts;active=/var/sieve/%u/active.sieve
           sieve_default = file:/var/sieve/%u/default.sieve
           sieve_default_name = default
+
+          # From elsewhere to Spam folder
+          imapsieve_mailbox1_name = Junk
+          imapsieve_mailbox1_causes = COPY
+          imapsieve_mailbox1_before = file:${stateDir}/imap_sieve/report-spam.sieve
+
+          # From Spam folder to elsewhere
+          imapsieve_mailbox2_name = *
+          imapsieve_mailbox2_from = Junk
+          imapsieve_mailbox2_causes = COPY
+          imapsieve_mailbox2_before = file:${stateDir}/imap_sieve/report-ham.sieve
+
+          sieve_pipe_bin_dir = ${pipeBin}/pipe/bin
+
+          sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment
         }
 
         lda_mailbox_autosubscribe = yes
         lda_mailbox_autocreate = yes
       '';
     };
+
+    systemd.services.dovecot2.preStart = ''
+      rm -rf '${stateDir}/imap_sieve'
+      mkdir '${stateDir}/imap_sieve'
+      cp -p "${./dovecot/imap_sieve}"/*.sieve '${stateDir}/imap_sieve/'
+      for k in "${stateDir}/imap_sieve"/*.sieve ; do
+        ${pkgs.dovecot_pigeonhole}/bin/sievec "$k"
+      done
+      chown -R '${dovecot2Cfg.mailUser}:${dovecot2Cfg.mailGroup}' '${stateDir}/imap_sieve'
+    '';
   };
 }