--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/99notify.sieve	Sun Jul 10 18:59:40 2016 +0800
@@ -0,0 +1,6 @@
+require ["vnd.dovecot.pipe", "copy", "variables"];
+if address :matches "to" "j*@example.com" {
+    if header :matches "from" "*" { set "from" "${1}"; }
+    if header :matches "subject" "*" { set "subject" "${1}"; }
+    pipe :copy :try "xmpp-headline.sh" ["${from}", "${subject}"];
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dovecot.sieve-pipe.conf	Sun Jul 10 18:59:40 2016 +0800
@@ -0,0 +1,7 @@
+plugin {
+    sieve = ~/.dovecot.sieve
+    sieve_dir = ~/sieve
+    sieve_plugins = sieve_extprograms
+    sieve_global_extensions = +vnd.dovecot.pipe
+    sieve_pipe_bin_dir = path/to/sieve-pipe
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xmpp-headline.sh	Sun Jul 10 18:59:40 2016 +0800
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+path/to/sieve-pipe/venv/bin/python path/to/sieve-pipe/xmpp-headline.py "$@"