feat(otlp): Derive a sentry.description attribute for V2 spans (#4832)

Very similar to #4796, but for
the `span.description` attribute. Supports [Span Field
Transition](https://linear.app/getsentry/document/span-field-transition-e0e4b8e59f11).

V2 spans probably will still have a description, but OTLP spans will
not. To make the transition easier, and to create a better experience in
the span waterfall, this PR derives a description for HTTP and database
spans based on the logic that exists in the [JavaScript
SDK](https://github.com/getsentry/sentry-javascript/blob/master/packages/opentelemetry/src/utils/parseSpanDescription.ts#L41-L94).
It's _slightly_ different from the SDK logic, but not in any important
way, from what I can tell.

1. If the payload includes a description, obeys the description as sent,
even if it's an empty string, and sets it as the `sentry.description`
attribute
2. If the payload does not include a `description` field, generate a
description and put it in the `sentry.description` attribute
3. If we cannot determine a good description, fall back to using the
`name` field, since it's similar in purpose

I also removed the little bit of current `description` processing, since
it all lives near the `op` processing now.

---------

Co-authored-by: Sebastian Zivota <loewenheim@users.noreply.github.com>

Author: gggritso

CHANGELOG.md

@@ -12,6 +12,7 @@
 - Update opentelemetry-proto and sentry-protos dependencies. ([#4847](https://github.com/getsentry/relay/pull/4847))
 - Take into account more types of tokens when doing AI cost calculation. ([#4840](https://github.com/getsentry/relay/pull/4840))
 - Use the `FiniteF64` type for measurements. ([#4828](https://github.com/getsentry/relay/pull/4828))
+- Derive a `sentry.description` attribute for V2 spans ([#4832](https://github.com/getsentry/relay/pull/4832))
 
 ## 25.6.1
 

Cargo.lock

@@ -24,6 +24,7 @@ opentelemetry-proto = { workspace = true, features = [
 relay-event-schema = { workspace = true }
 relay-protocol = { workspace = true }
 serde_json = { workspace = true }
+url = { workspace = true }
 
 [dev-dependencies]
 insta = { workspace = true }

relay-spans/Cargo.toml

@@ -11,8 +11,9 @@ use relay_protocol::Error;
 ///   if the OTEL span's `name` is empty.
 /// * The Sentry span's `op` field will be inferred based on the OTEL span's `sentry.op` attribute,
 ///   or other available attributes if `sentry.op` is not provided.
-/// * The Sentry span's `description` field may be set based on `db` or `http` attributes
-///   if the OTEL span's `sentry.description` attribute is empty.
+/// * The Sentry span's `description` field will be inferred based on the OTEL span's
+///   `sentry.description` attribute, or other available attributes if `sentry.description` is not
+///   provided.
 /// * The Sentry span's `status` field is set based on the OTEL span's `status` field and
 ///   `http.status_code` and `rpc.grpc.status_code` attributes.
 /// * The Sentry span's `exclusive_time` field is set based on the OTEL span's `exclusive_time_nano`
@@ -39,7 +40,7 @@ mod tests {
             "spanId": "e342abb1214ca181",
             "parentSpanId": "0c7a7dea069bf5a6",
             "name": "middleware - fastify -> @fastify/multipart",
-            "kind": 1,
+            "kind": 2,
             "startTimeUnixNano": "1697620454980000000",
             "endTimeUnixNano": "1697620454980078800",
             "attributes": [
@@ -115,7 +116,7 @@ mod tests {
           "timestamp": 1697620454.980079,
           "start_timestamp": 1697620454.98,
           "exclusive_time": 1000.0,
-          "op": "http",
+          "op": "http.server",
           "span_id": "e342abb1214ca181",
           "parent_span_id": "0c7a7dea069bf5a6",
           "trace_id": "89143b0763095bd9c9955e8175d1fb23",
@@ -133,7 +134,7 @@ mod tests {
             "sentry.sample_rate": 1
           },
           "links": [],
-          "kind": "internal"
+          "kind": "server"
         }
         "###);
     }
@@ -170,6 +171,7 @@ mod tests {
           "parent_span_id": "0c7a7dea069bf5a6",
           "trace_id": "89143b0763095bd9c9955e8175d1fb23",
           "status": "unknown",
+          "description": "middleware - fastify -> @fastify/multipart",
           "data": {
             "sentry.name": "middleware - fastify -> @fastify/multipart"
           },
@@ -203,6 +205,7 @@ mod tests {
           "parent_span_id": "0c7a7dea069bf5a6",
           "trace_id": "89143b0763095bd9c9955e8175d1fb23",
           "status": "unknown",
+          "description": "middleware - fastify -> @fastify/multipart",
           "data": {
             "sentry.name": "middleware - fastify -> @fastify/multipart"
           },
@@ -223,6 +226,12 @@ mod tests {
             "startTimeUnixNano": "1697620454980000000",
             "endTimeUnixNano": "1697620454980078800",
             "attributes": [
+                {
+                    "key" : "db.system",
+                    "value": {
+                        "stringValue": "mysql"
+                    }
+                },
                 {
                     "key" : "db.name",
                     "value": {
@@ -251,13 +260,14 @@ mod tests {
           "timestamp": 1697620454.980079,
           "start_timestamp": 1697620454.98,
           "exclusive_time": 0.0788,
-          "op": "default",
+          "op": "db",
           "span_id": "e342abb1214ca181",
           "parent_span_id": "0c7a7dea069bf5a6",
           "trace_id": "89143b0763095bd9c9955e8175d1fb23",
           "status": "unknown",
           "description": "SELECT \"table\".\"col\" FROM \"table\" WHERE \"table\".\"col\" = %s",
           "data": {
+            "db.system": "mysql",
             "db.name": "database",
             "db.statement": "SELECT \"table\".\"col\" FROM \"table\" WHERE \"table\".\"col\" = %s",
             "db.type": "sql",
@@ -339,7 +349,7 @@ mod tests {
             "spanId": "e342abb1214ca181",
             "parentSpanId": "0c7a7dea069bf5a6",
             "name": "http client request",
-            "kind": 3,
+            "kind": 2,
             "startTimeUnixNano": "1697620454980000000",
             "endTimeUnixNano": "1697620454980078800",
             "attributes": [
@@ -365,7 +375,7 @@ mod tests {
           "timestamp": 1697620454.980079,
           "start_timestamp": 1697620454.98,
           "exclusive_time": 0.0788,
-          "op": "http.client",
+          "op": "http.server",
           "span_id": "e342abb1214ca181",
           "parent_span_id": "0c7a7dea069bf5a6",
           "trace_id": "89143b0763095bd9c9955e8175d1fb23",
@@ -377,7 +387,7 @@ mod tests {
             "url.path": "/api/search?q=foobar"
           },
           "links": [],
-          "kind": "client"
+          "kind": "server"
         }
         "###);
     }

relay-spans/src/otel_to_sentry.rs

@@ -54,36 +54,23 @@ pub fn otel_to_sentry_span(otel_span: OtelSpan) -> Result<SentrySpanV2, Error> {
 
     let mut sentry_attributes = Attributes::new();
     let mut name = if name.is_empty() { None } else { Some(name) };
-    let mut description = None;
-    let mut http_method = None;
-    let mut http_route = None;
 
     for (key, value) in attributes.into_iter().flat_map(|attribute| {
         let value = attribute.value?.value?;
         Some((attribute.key, value))
     }) {
         match key.as_str() {
-            "sentry.description" => {
-                description = otel_value_to_string(value.clone());
-            }
             key if key.starts_with("db") => {
                 name = name.or(Some("db".to_owned()));
-                if key == "db.statement" {
-                    description = description.or_else(|| otel_value_to_string(value.clone()));
-                }
             }
             "http.method" | "http.request.method" => {
                 let http_op = match kind {
                     2 => "http.server",
                     3 => "http.client",
                     _ => "http",
                 };
-                http_method = otel_value_to_string(value.clone());
                 name = name.or(Some(http_op.to_owned()));
             }
-            "http.route" | "url.path" => {
-                http_route = otel_value_to_string(value.clone());
-            }
             _ => (),
         }
 
@@ -92,15 +79,6 @@ pub fn otel_to_sentry_span(otel_span: OtelSpan) -> Result<SentrySpanV2, Error> {
         }
     }
 
-    if let (Some(http_method), Some(http_route)) = (http_method, http_route) {
-        description = description.or_else(|| Some(format!("{http_method} {http_route}")));
-    }
-
-    // Put the fixed up description back into the attributes
-    if let Some(description) = description {
-        sentry_attributes.insert("sentry.description".into(), description);
-    }
-
     let sentry_links: Vec<Annotated<SpanV2Link>> = links
         .into_iter()
         .map(|link| otel_to_sentry_link(link).map(Into::into))
@@ -126,17 +104,6 @@ pub fn otel_to_sentry_span(otel_span: OtelSpan) -> Result<SentrySpanV2, Error> {
     Ok(event_span)
 }
 
-fn otel_value_to_string(value: OtelValue) -> Option<String> {
-    match value {
-        OtelValue::StringValue(v) => Some(v),
-        OtelValue::BoolValue(v) => Some(v.to_string()),
-        OtelValue::IntValue(v) => Some(v.to_string()),
-        OtelValue::DoubleValue(v) => Some(v.to_string()),
-        OtelValue::BytesValue(v) => String::from_utf8(v).ok(),
-        _ => None,
-    }
-}
-
 fn otel_flags_is_remote(value: u32) -> Option<bool> {
     if value & OtelSpanFlags::ContextHasIsRemoteMask as u32 == 0 {
         None
@@ -418,10 +385,6 @@ mod tests {
             "db.type": {
               "type": "string",
               "value": "sql"
-            },
-            "sentry.description": {
-              "type": "string",
-              "value": "SELECT \"table\".\"col\" FROM \"table\" WHERE \"table\".\"col\" = %s"
             }
           }
         }
@@ -543,10 +506,6 @@ mod tests {
               "type": "string",
               "value": "GET"
             },
-            "sentry.description": {
-              "type": "string",
-              "value": "GET /api/search?q=foobar"
-            },
             "url.path": {
               "type": "string",
               "value": "/api/search?q=foobar"