fix(api): record client cancellations as 499 in metrics and traces

Follow-up to 164f31a - applies client cancellation handling to the
metrics and tracing middlewares. Cancelled requests are now recorded
with http.status_code=499 (nginx convention for client-closed-request),
preventing them from inflating the 5xx error rate.

Also always records both a grouped status code (http.status_code, e.g.
400/500) and a granular one (http.status_code_granular, e.g. 404/499),
removing the groupedStatus config toggle.

Author: dobrac

packages/api/internal/middleware/otel/metrics/config.go

@@ -11,7 +11,6 @@ type config struct {
 	recordInFlight bool
 	recordSize     bool
 	recordDuration bool
-	groupedStatus  bool
 	recorder       Recorder
 	attributes     func(serverName, route string, request *http.Request) []attribute.KeyValue
 	shouldRecord   func(serverName, route string, request *http.Request) bool
@@ -22,7 +21,6 @@ func defaultConfig() *config {
 		recordInFlight: true,
 		recordDuration: true,
 		recordSize:     true,
-		groupedStatus:  true,
 		attributes:     DefaultAttributes,
 		shouldRecord: func(_, _ string, _ *http.Request) bool {
 			return true

packages/api/internal/middleware/otel/metrics/middleware.go

@@ -19,6 +19,8 @@ const MetricPrefix = "metric."
 // (after body parsing) began. This allows metrics to exclude body upload/parsing time.
 const processingStartTimeKey = "metrics.processingStartTime"
 
+const HTTPStatusCodeGranularKey = attribute.Key("http.status_code_granular")
+
 // SetProcessingStartTime stores the current time as the processing start time in the gin context.
 func SetProcessingStartTime(c *gin.Context) {
 	c.Set(processingStartTimeKey, time.Now())
@@ -73,17 +75,16 @@ func Middleware(meterProvider metric.MeterProvider, service string, options ...O
 				reqAttributes...,
 			)
 
+			code := ginCtx.Writer.Status()
 			if errors.Is(ctx.Err(), context.Canceled) {
 				// 499 is the nginx convention for "client closed request before server responded"
-				resAttributes = append(resAttributes, semconv.HTTPStatusCodeKey.Int(499))
-				resAttributes = append(resAttributes, attribute.Bool("client.canceled", true))
-			} else if cfg.groupedStatus {
-				code := ginCtx.Writer.Status() / 100 * 100
-				resAttributes = append(resAttributes, semconv.HTTPStatusCodeKey.Int(code))
-			} else {
-				resAttributes = append(resAttributes, semconv.HTTPAttributesFromHTTPStatusCode(ginCtx.Writer.Status())...)
+				code = 499
 			}
 
+			groupedCode := code / 100 * 100
+			resAttributes = append(resAttributes, semconv.HTTPStatusCodeKey.Int(groupedCode))
+			resAttributes = append(resAttributes, HTTPStatusCodeGranularKey.Int(code))
+
 			// Append attributes from ginCtx
 			resAttributes = append(resAttributes, attributesFromGinContext(ginCtx, MetricPrefix)...)
 

packages/api/internal/middleware/otel/tracing/middleware.go

@@ -112,12 +112,13 @@ func Middleware(tracerProvider oteltrace.TracerProvider, service string) gin.Han
 		c.Next()
 
 		status := c.Writer.Status()
-		attrs := semconv.HTTPAttributesFromHTTPStatusCode(status)
-		span.SetAttributes(attrs...)
-
 		if errors.Is(ctx.Err(), context.Canceled) {
+			// 499 is the nginx convention for "client closed request before server responded"
+			span.SetAttributes(semconv.HTTPAttributesFromHTTPStatusCode(499)...)
 			span.SetAttributes(attribute.Bool("client.canceled", true))
 		} else {
+			attrs := semconv.HTTPAttributesFromHTTPStatusCode(status)
+			span.SetAttributes(attrs...)
 			spanStatus, spanMessage := semconv.SpanStatusFromHTTPStatusCode(status)
 			span.SetStatus(spanStatus, spanMessage)
 		}