fix regression of query range result cache unable to parse old cached results (#6196)

Author: yeya24

pkg/querier/tripperware/custom.go

@@ -1,28 +1,5 @@
 package tripperware
 
-import (
-	"fmt"
-
-	"github.com/gogo/protobuf/types"
-)
-
-func (e *Extent) ToResponse() (Response, error) {
-	msg, err := types.EmptyAny(e.Response)
-	if err != nil {
-		return nil, err
-	}
-
-	if err := types.UnmarshalAny(e.Response, msg); err != nil {
-		return nil, err
-	}
-
-	resp, ok := msg.(Response)
-	if !ok {
-		return nil, fmt.Errorf("bad cached type")
-	}
-	return resp, nil
-}
-
 func (m *Sample) GetTimestampMs() int64 {
 	if m != nil {
 		if m.Sample != nil {

pkg/querier/tripperware/instantquery/instant_query.go

@@ -66,7 +66,7 @@ func (c instantQueryCodec) DecodeRequest(_ context.Context, r *http.Request, for
 }
 
 func (instantQueryCodec) DecodeResponse(ctx context.Context, r *http.Response, _ tripperware.Request) (tripperware.Response, error) {
-	log, ctx := spanlogger.New(ctx, "tripperware.PrometheusResponse") //nolint:ineffassign,staticcheck
+	log, ctx := spanlogger.New(ctx, "DecodeQueryInstantResponse") //nolint:ineffassign,staticcheck
 	defer log.Finish()
 
 	if err := ctx.Err(); err != nil {

pkg/querier/tripperware/queryrange/query_range.go

@@ -41,6 +41,20 @@ var (
 	cacheControlHeader = "Cache-Control"
 )
 
+func (resp *PrometheusResponse) HTTPHeaders() map[string][]string {
+	if resp != nil && resp.GetHeaders() != nil {
+		r := map[string][]string{}
+		for _, header := range resp.GetHeaders() {
+			if header != nil {
+				r[header.Name] = header.Values
+			}
+		}
+
+		return r
+	}
+	return nil
+}
+
 type prometheusCodec struct {
 	sharded bool
 }
@@ -57,6 +71,11 @@ func (c prometheusCodec) MergeResponse(ctx context.Context, req tripperware.Requ
 		return tripperware.NewEmptyPrometheusResponse(false), nil
 	}
 
+	// Safety guard in case any response from results cache middleware
+	// still uses the old queryrange.PrometheusResponse type.
+	for i, resp := range responses {
+		responses[i] = convertToTripperwarePrometheusResponse(resp)
+	}
 	return tripperware.MergeResponse(ctx, c.sharded, nil, responses...)
 }