feat: Log disabled recipients (#113)

Logs disabled recipient addresses
when removing them from RCPT TO.

Signed-off-by: Jagoda Ślązak <jslazak@jslazak.com>

filtermail/src/inbound.rs

@@ -101,7 +101,13 @@ impl SmtpHandler for IncomingBeforeQueueHandler {
         envelope.rcpt_to = envelope
             .rcpt_to
             .iter()
-            .filter(|s| !self.config.is_disabled(s))
+            .filter(|s| {
+                let disabled = self.config.is_disabled(s);
+                if disabled {
+                    log::warn!("Disabled recipient: {s}; removing from RCPT TO");
+                }
+                !disabled
+            })
             .cloned()
             .collect();
 

filtermail/src/outbound.rs

@@ -81,7 +81,13 @@ impl SmtpHandler for OutgoingBeforeQueueHandler {
         envelope.rcpt_to = envelope
             .rcpt_to
             .iter()
-            .filter(|s| !self.config.is_disabled(s))
+            .filter(|s| {
+                let disabled = self.config.is_disabled(s);
+                if disabled {
+                    log::warn!("Disabled recipient: {s}; removing from RCPT TO");
+                }
+                !disabled
+            })
             .cloned()
             .collect();