Instrumentation: Handle context.Canceled (#75867)

Ref #68480

Co-authored-by: Giuseppe Guerra <giuseppe.guerra@grafana.com>

pkg/api/response/response.go

@@ -2,6 +2,7 @@ package response
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -18,6 +19,9 @@ import (
 	"github.com/grafana/grafana/pkg/util/errutil"
 )
 
+var errRequestCanceledBase = errutil.ClientClosedRequest("api.requestCanceled",
+	errutil.WithPublicMessage("Request canceled"))
+
 // Response is an HTTP response interface.
 type Response interface {
 	// WriteTo writes to a context.
@@ -286,12 +290,18 @@ func Err(err error) *NormalResponse {
 // The signature is equivalent to that of Error which allows us to
 // rename this to Error when we're confident that that would be safe to
 // do.
+// If the error provided is not an errutil.Error and is/wraps context.Canceled
+// the function returns an Err(errRequestCanceledBase).
 func ErrOrFallback(status int, message string, err error) *NormalResponse {
 	grafanaErr := errutil.Error{}
 	if errors.As(err, &grafanaErr) {
 		return Err(err)
 	}
 
+	if errors.Is(err, context.Canceled) {
+		return Err(errRequestCanceledBase.Errorf("response: request canceled: %w", err))
+	}
+
 	return Error(status, message, err)
 }