chore(telemetry): remove span name from attributes in Sentry (#10278)

Before sending logs to Sentry, we perform a pass over them to make them
somewhat look like the output of `tracing_subscriber::fmt`. In
particular, we trim the span name from fields in order to shorten the
message. In our logger config, we don't render the span name at all and
just append all fields at the end of the message.

Sentry supports filtering by field names but unfortunately, those cannot
contain a colon (`:`). Given that we already trim the span name in the
actual message, it also makes sense to remove the span name from the
actual attributes. That allows us to actually filter by these attributes
and has the additional advantage that fields from different spans with
the same name are merged. This is especially useful because we purposely
reuse names like `cid` to refer the current connection from different
spans.

rust/telemetry/src/lib.rs

@@ -3,7 +3,7 @@
 use std::{
     borrow::Cow,
     collections::BTreeMap,
-    fmt,
+    fmt, mem,
     net::{SocketAddr, ToSocketAddrs as _},
     str::FromStr,
     sync::Arc,
@@ -371,21 +371,24 @@ fn append_tracing_fields_to_message(mut log: Log) -> Option<Log> {
         "parent_span_id",
     ];
 
-    for (key, attribute) in &log.attributes {
+    for (key, attribute) in mem::take(&mut log.attributes) {
         let LogAttribute(serde_json::Value::String(attr_string)) = &attribute else {
             continue;
         };
 
         if IGNORED_ATTRS.iter().any(|attr| key.starts_with(attr)) {
+            log.attributes.insert(key, attribute);
+
             continue;
         }
 
         let key = match key.rsplit_once(':') {
             Some((_, key)) => key,
-            None => key,
+            None => &key,
         };
 
         log.body.push_str(&format!(" {key}={attr_string}"));
+        log.attributes.insert(key.to_owned(), attribute);
     }
 
     Some(log)
@@ -504,6 +507,38 @@ mod tests {
         )
     }
 
+    #[test]
+    fn trims_name_of_span_from_attribute() {
+        let log = log(
+            "Foobar",
+            &[
+                ("handle_input:class", "success response"),
+                ("handle_input:from", "1.1.1.1:3478"),
+                ("handle_input:method", "binding"),
+            ],
+        );
+
+        let log = append_tracing_fields_to_message(log).unwrap();
+
+        assert_eq!(
+            log.attributes,
+            BTreeMap::from([
+                (
+                    "class".to_owned(),
+                    LogAttribute(serde_json::Value::String("success response".to_owned()))
+                ),
+                (
+                    "from".to_owned(),
+                    LogAttribute(serde_json::Value::String("1.1.1.1:3478".to_owned()))
+                ),
+                (
+                    "method".to_owned(),
+                    LogAttribute(serde_json::Value::String("binding".to_owned()))
+                )
+            ])
+        )
+    }
+
     fn event(msg: &str) -> Event<'static> {
         Event {
             message: Some(msg.to_owned()),