adopt more compact representation of ResolvedAddress in logs/diagnostics

Previously we'd use the Debug impl of ResolvedAddress, which rendered
like `ResolvedAddress { name: "some.host.", addr: "10.0.0.1" }`, which
is a bit heavyweight when it shows up in a log where we're indicating
that none of the hosts could be connected.

This commit adds a Display impl that renders that same struct in a
more compact form: `some.host./10.0.0.1`.

crates/kumo-log-types/src/lib.rs

@@ -18,6 +18,12 @@ pub struct ResolvedAddress {
     pub addr: IpAddr,
 }
 
+impl std::fmt::Display for ResolvedAddress {
+    fn fmt(&self, fmt: &mut std::fmt::Formatter) -> std::fmt::Result {
+        write!(fmt, "{}/{}", self.name, self.addr)
+    }
+}
+
 #[derive(Serialize, Deserialize, Debug, Copy, Clone, Eq, PartialEq, Hash, Ord, PartialOrd)]
 pub enum RecordType {
     /// Recorded by a receiving listener

crates/kumod/src/smtp_dispatcher.rs

@@ -179,7 +179,7 @@ impl SmtpDispatcher {
                             detail: 4,
                         }),
                         content: format!(
-                            "{addr:?} is on the list of prohibited_hosts {:?}",
+                            "{addr} is on the list of prohibited_hosts {:?}",
                             path_config.prohibited_hosts
                         ),
                         command: None,
@@ -276,10 +276,10 @@ impl SmtpDispatcher {
             .egress_source
             .remote_port
             .unwrap_or(path_config.smtp_port);
-        let connect_context = format!("connect to {address:?} port {port} and read initial banner");
+        let connect_context = format!("connect to {address} port {port} and read initial banner");
 
         self.tracer.diagnostic(Level::INFO, || {
-            format!("Attempting connection to {address:?} port {port}")
+            format!("Attempting connection to {address} port {port}")
         });
 
         let make_connection = {
@@ -301,7 +301,7 @@ impl SmtpDispatcher {
                     .await?;
 
                 tracing::debug!(
-                    "connected to {address:?} port {port} via source address {source_address:?}"
+                    "connected to {address} port {port} via source address {source_address:?}"
                 );
 
                 let mut client = SmtpClient::with_stream(stream, &mx_host, timeouts);
@@ -341,7 +341,7 @@ impl SmtpDispatcher {
         let pretls_caps = client
             .ehlo(&ehlo_name)
             .await
-            .with_context(|| format!("{address:?}:{port}: EHLO after banner"))?;
+            .with_context(|| format!("{address}:{port}: EHLO after banner"))?;
 
         // Use STARTTLS if available.
         let has_tls = pretls_caps.contains_key("STARTTLS");
@@ -493,7 +493,7 @@ impl SmtpDispatcher {
                 {
                     TlsStatus::FailedHandshake(handshake_error) => {
                         tracing::debug!(
-                            "TLS handshake with {address:?}:{port} failed: \
+                            "TLS handshake with {address}:{port} failed: \
                         {handshake_error}, but continuing in clear text because \
                         we are in OpportunisticInsecure mode"
                         );
@@ -518,7 +518,7 @@ impl SmtpDispatcher {
                     self.remember_broken_tls(&dispatcher.name, &path_config);
                     OpportunisticInsecureTlsHandshakeError {
                         error,
-                        address: format!("{address:?}:{port}"),
+                        address: format!("{address}:{port}"),
                         label,
                     }
                 })?;

docs/changelog/main.md

@@ -10,6 +10,11 @@
 
 * Updated embedded libunbound to 1.22
 
+* Use more compact representation of ResolvedAddress in logs. Instead of
+  showing something like `ResolvedAddress { name: "some.host.", addr: 10.0.0.1 }`
+  we now display it as `some.host./10.0.0.1` which is a bit easier to
+  understand and occupies less space in the logs.
+
 ## Fixes
 
 * When `enable_tls` is set to `Required` or `RequiredInsecure`, ignore the