refactor: Implement Display for AddressDomain

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

filtermail/src/transport.rs

@@ -68,10 +68,7 @@ where
             return Ok(());
         }
 
-        log::trace!(
-            "Trying to acquire a permit for {} worker...",
-            domain.as_ref()
-        );
+        log::trace!("Trying to acquire a permit for {domain} worker...",);
         if let Some(permit) = self.workers.get_permit(&domain) {
             transaction.state.permits.insert(domain, permit);
         }

filtermail/src/transport/worker.rs

@@ -100,10 +100,7 @@ where
             if let Some(w) = &worker
                 && w.handle.is_finished()
             {
-                log::error!(
-                    "Worker for destination {} crashed! Restarting...",
-                    destination.as_ref()
-                );
+                log::error!("Worker for destination {destination} crashed! Restarting...",);
                 worker = None;
                 {
                     let mut map = self.inner.write();
@@ -180,10 +177,7 @@ impl Worker {
             .map(|id| id.to_string())
             .unwrap_or("?".to_string());
 
-        log::info!(
-            "Starting worker {worker_id} for destination {}",
-            destination.as_ref()
-        );
+        log::info!("Starting worker {worker_id} for destination {destination}");
 
         let tls_resumption_store = Arc::new(rustls::client::ClientSessionMemoryCache::new(256));
         let https_client = HttpsClient::new(tls_resumption_store.clone())?;
@@ -206,8 +200,7 @@ impl Worker {
             .await;
             if message.response_tx.send(result).is_err() {
                 log::error!(
-                    "Worker {worker_id} ({}) failed to send response to transport handler.",
-                    destination.as_ref()
+                    "Worker {worker_id} ({destination}) failed to send response to transport handler."
                 );
             };
         }

filtermail/src/utils.rs

@@ -1,5 +1,6 @@
 use hickory_resolver::{TokioResolver, proto::dnssec::TrustAnchors};
 use mailparse::MailAddr;
+use std::fmt::{Display, Formatter};
 use std::path::PathBuf;
 use std::str::FromStr;
 use std::sync::Arc;
@@ -88,6 +89,24 @@ impl AsRef<str> for AddressDomain {
     }
 }
 
+impl Display for AddressDomain {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        match self {
+            AddressDomain::Literal(addr) => {
+                // naive check, but should be enough as long as `AddressDomain`
+                // is constructed using parse/from_str.
+                write!(f, "[")?;
+                if addr.contains(':') {
+                    write!(f, "IPv6:")?;
+                }
+                write!(f, "{addr}]")?;
+            }
+            AddressDomain::Name(domain) => write!(f, "{domain}")?,
+        };
+        Ok(())
+    }
+}
+
 /// Logs email to `/tmp/filtermail-rejected/<reason>/<timestamp>.eml`
 /// and returns the file path.
 ///
@@ -160,4 +179,20 @@ mod tests {
         let result = AddressDomain::from_str(input).ok();
         assert_eq!(result, expected);
     }
+
+    #[rstest]
+    #[case::domain(AddressDomain::Name("example.org".to_string()), "example.org")]
+    #[case::ipv4(AddressDomain::Literal("192.0.2.0".to_string()), "192.0.2.0")]
+    #[case::ipv6(AddressDomain::Literal("2001:db8::1".to_string()), "2001:db8::1")]
+    fn test_address_domain_as_ref(#[case] input: AddressDomain, #[case] expected: &str) {
+        assert_eq!(input.as_ref(), expected);
+    }
+
+    #[rstest]
+    #[case::domain(AddressDomain::Name("example.org".to_string()), "example.org")]
+    #[case::ipv4(AddressDomain::Literal("192.0.2.0".to_string()), "[192.0.2.0]")]
+    #[case::ipv6(AddressDomain::Literal("2001:db8::1".to_string()), "[IPv6:2001:db8::1]")]
+    fn test_address_domain_display(#[case] input: AddressDomain, #[case] expected: &str) {
+        assert_eq!(&format!("{input}"), expected);
+    }
 }