Properly fix the wrong logging of 200 when write to client fails

CHANGELOG.md

@@ -88,7 +88,7 @@
 * [BUGFIX] Ring: Fixed a situation where upgrading from pre-1.0 cortex with a rolling strategy caused new 1.0 ingesters to lose their zone value in the ring until manually forced to re-register. #2404
 * [BUGFIX] Distributor: `/all_user_stats` now show API and Rule Ingest Rate correctly. #2457
 * [BUGFIX] Fixed `version`, `revision` and `branch` labels exported by the `cortex_build_info` metric. #2468
-* [BUGFIX] QueryFrontend: fixed a situation where HTTP error is ignored and an incorrect status code is set. #2483
+* [BUGFIX] QueryFrontend: fixed a situation where HTTP error is ignored and an incorrect status code is set. #2590
 * [BUGFIX] QueryFrontend: fixed a situation where span context missed when downstream_url is used. #2539
 * [BUGFIX] Querier: Fixed a situation where querier would crash because of an unresponsive frontend instance. #2569
 * [BUGFIX] Fixed collection of tracing spans from Thanos components used internally. #2584

go.mod

@@ -52,7 +52,7 @@ require (
 	github.com/stretchr/testify v1.4.0
 	github.com/thanos-io/thanos v0.12.3-0.20200507181659-b9ff23c5c31d
 	github.com/uber/jaeger-client-go v2.20.1+incompatible
-	github.com/weaveworks/common v0.0.0-20200511094620-c4a9ff77246b
+	github.com/weaveworks/common v0.0.0-20200512154658-384f10054ec5
 	go.etcd.io/bbolt v1.3.3
 	go.etcd.io/etcd v0.0.0-20191023171146-3cf2f69b5738
 	go.uber.org/atomic v1.5.1

pkg/querier/frontend/frontend.go

@@ -192,11 +192,7 @@ func (f *Frontend) handle(w http.ResponseWriter, r *http.Request) {
 		hs[h] = vs
 	}
 	w.WriteHeader(resp.StatusCode)
-
-	if _, err = io.Copy(w, resp.Body); err != nil {
-		server.WriteError(w, err)
-		return
-	}
+	io.Copy(w, resp.Body)
 }
 
 func writeError(w http.ResponseWriter, err error) {