Use errdefs package

vkubelet/api/stats.go

@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"net/http"
 
-	"github.com/cpuguy83/strongerrors"
 	"github.com/pkg/errors"
 	stats "k8s.io/kubernetes/pkg/kubelet/apis/stats/v1alpha1"
 )
@@ -21,20 +20,36 @@ func HandlePodStatsSummary(h PodStatsSummaryHandlerFunc) http.HandlerFunc {
 	return handleError(func(w http.ResponseWriter, req *http.Request) error {
 		stats, err := h(req.Context())
 		if err != nil {
-			if errors.Cause(err) == context.Canceled {
-				return strongerrors.Cancelled(err)
+			if isCancelled(err) {
+				return err
 			}
 			return errors.Wrap(err, "error getting status from provider")
 		}
 
 		b, err := json.Marshal(stats)
 		if err != nil {
-			return strongerrors.Unknown(errors.Wrap(err, "error marshalling stats"))
+			return errors.Wrap(err, "error marshalling stats")
 		}
 
 		if _, err := w.Write(b); err != nil {
-			return strongerrors.Unknown(errors.Wrap(err, "could not write to client"))
+			return errors.Wrap(err, "could not write to client")
 		}
 		return nil
 	})
 }
+
+func isCancelled(err error) bool {
+	if err == context.Canceled {
+		return true
+	}
+
+	if e, ok := err.(causal); ok {
+		return isCancelled(e.Cause())
+	}
+	return false
+}
+
+type causal interface {
+	Cause() error
+	error
+}