fix(otlp): add OTLP trace endpoint without trailing slash

CHANGELOG.md

@@ -36,6 +36,7 @@
 - Serialize span's `_meta` information when producing to Kafka. ([#4646](https://github.com/getsentry/relay/pull/4646))
 - Enable connection pooling for asynchronous Redis connections. ([#4622](https://github.com/getsentry/relay/pull/4622))
 - Add the internal `_performance_issues_spans` field to control perf issue detection. ([#4652](https://github.com/getsentry/relay/pull/4652))
+- Add `/v1/traces` (without a trailing slash) as a spec-compliant alternative for our OTLP traces endpoint. ([#4655](https://github.com/getsentry/relay/pull/4655))
 - Improve handling of failed Redis connections. ([#4657](https://github.com/getsentry/relay/pull/4657))
 
 ## 25.3.0

relay-server/src/endpoints/mod.rs

@@ -78,6 +78,11 @@ pub fn routes(config: &Config) -> Router<ServiceState>{
         .route("/api/{project_id}/playstation/", playstation::route(config))
         .route("/api/{project_id}/events/{event_id}/attachments/", post(attachments::handle))
         .route("/api/{project_id}/unreal/{sentry_key}/", unreal::route(config))
+        // The OTLP/HTTP transport defaults to a request suffix of /v1/traces (no trailing slash):
+        // https://opentelemetry.io/docs/specs/otlp/#otlphttp-request
+        // Because we initially released this endpoint with a trailing slash, keeping it for
+        // backwards compatibility.
+        .route("/api/{project_id}/otlp/v1/traces", traces::route(config))
         .route("/api/{project_id}/otlp/v1/traces/", traces::route(config))
         // NOTE: If you add a new (non-experimental) route here, please also list it in
         // https://github.com/getsentry/sentry-docs/blob/master/docs/product/relay/operating-guidelines.mdx

tests/integration/fixtures/__init__.py

@@ -216,7 +216,7 @@ def send_otel_span(
         if dsn_key is None:
             dsn_key = self.get_dsn_public_key(project_id, dsn_key_idx)
 
-        url = f"/api/{project_id}/otlp/v1/traces/?sentry_key={dsn_key}"
+        url = f"/api/{project_id}/otlp/v1/traces?sentry_key={dsn_key}"
 
         if json:
             headers = {