Fixes after rebase, and review comments.

Signed-off-by: Tom Wilkie <[email protected]>

Author: tomwilkie

Makefile

@@ -50,6 +50,7 @@ $(foreach exe, $(EXES), $(eval $(call dep_exe, $(exe))))
 pkg/ingester/client/cortex.pb.go: pkg/ingester/client/cortex.proto
 pkg/ring/ring.pb.go: pkg/ring/ring.proto
 pkg/querier/frontend/frontend.pb.go: pkg/querier/frontend/frontend.proto
+pkg/querier/queryrange/queryrange.pb.go: pkg/querier/queryrange/queryrange.proto
 pkg/chunk/storage/caching_index_client.pb.go: pkg/chunk/storage/caching_index_client.proto
 pkg/distributor/ha_tracker.pb.go: pkg/distributor/ha_tracker.proto
 all: $(UPTODATE_FILES)

pkg/chunk/cache/cache.go

@@ -7,6 +7,12 @@ import (
 )
 
 // Cache byte arrays by key.
+//
+// NB we intentionally do not return errors in this interface - caching is best
+// effort by definition.  We found that when these methods did return errors,
+// the caller would just log them - so its easier for implementation to do that.
+// Whatsmore, we found partially successful Fetchs were often treated as failed
+// when they returned an error.
 type Cache interface {
 	Store(ctx context.Context, key []string, buf [][]byte)
 	Fetch(ctx context.Context, keys []string) (found []string, bufs [][]byte, missing []string)

pkg/chunk/cache/memcached.go

@@ -66,7 +66,6 @@ type Memcached struct {
 }
 
 // NewMemcached makes a new Memcache.
-// TODO(bwplotka): Return error instead of just log line.
 // TODO(bwplotka): Fix metrics, get them out of globals, separate or allow prefixing.
 // TODO(bwplotka): Remove globals & util packages from cache package entirely (e.g util.Logger).
 func NewMemcached(cfg MemcachedConfig, client MemcachedClient, name string) *Memcached {

pkg/querier/frontend/frontend_test.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"sync/atomic"
 	"testing"
 	"time"
 

pkg/querier/queryrange/queryrange.pb.go

@@ -4,10 +4,10 @@ import (
 	"context"
 	"flag"
 	"fmt"
-	"log"
 	"sort"
 	"time"
 
+	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/gogo/protobuf/proto"
 	opentracing "github.com/opentracing/opentracing-go"
@@ -257,6 +257,10 @@ func jaegerTraceID(ctx context.Context) string {
 		return ""
 	}
 
-	spanContext := span.Context().(jaeger.SpanContext)
+	spanContext, ok := span.Context().(jaeger.SpanContext)
+	if !ok {
+		return ""
+	}
+
 	return spanContext.TraceID().String()
 }