feat(blooms): ignore individual bloom-gw failures

pkg/bloomgateway/client.go

@@ -14,6 +14,7 @@ import (
 	ringclient "github.com/grafana/dskit/ring/client"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
+	"go.uber.org/atomic"
 	"golang.org/x/exp/slices"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/health/grpc_health_v1"
@@ -238,20 +239,8 @@ func (c *GatewayClient) FilterChunks(ctx context.Context, _ string, interval blo
 		}
 	}
 
-	if len(servers) > 0 {
-		// cache locality score (higher is better):
-		// `% keyspace / % instances`. Ideally converges to 1 (querying x% of keyspace requires x% of instances),
-		// but can be less if the keyspace is not evenly distributed across instances. Ideal operation will see the range of
-		// `1-2/num_instances` -> `1`, where the former represents slight
-		// overlap on instances to the left and right of the range.
-		pctKeyspace := float64(lastFp-firstFp) / float64(math.MaxUint64)
-		pctInstances := float64(len(servers)) / float64(max(1, len(c.pool.Addrs())))
-		cacheLocalityScore := pctKeyspace / pctInstances
-		c.metrics.cacheLocalityScore.Observe(cacheLocalityScore)
-	}
-
 	results := make([][]*logproto.GroupedChunkRefs, len(servers))
-	count := 0
+	count := atomic.NewInt64(0)
 	err := concurrency.ForEachJob(ctx, len(servers), len(servers), func(ctx context.Context, i int) error {
 		rs := servers[i]
 
@@ -269,10 +258,24 @@ func (c *GatewayClient) FilterChunks(ctx context.Context, _ string, interval blo
 			}
 			resp, err := client.FilterChunkRefs(ctx, req)
 			if err != nil {
-				return err
+				// We don't want a single bloom-gw failure to fail the entire query,
+				// so instrument & move on
+				level.Error(c.logger).Log(
+					"msg", "filter failed for instance, skipping",
+					"addr", rs.addr,
+					"series", len(rs.groups),
+					"blocks", len(rs.blocks),
+					"err", err,
+				)
+				// filter none of the results on failed request
+				c.metrics.clientRequests.WithLabelValues(typeError).Inc()
+				results[i] = rs.groups
+			} else {
+				c.metrics.clientRequests.WithLabelValues(typeSuccess).Inc()
+				results[i] = resp.ChunkRefs
 			}
-			results[i] = resp.ChunkRefs
-			count += len(resp.ChunkRefs)
+
+			count.Add(int64(len(results[i])))
 			return nil
 		})
 	})
@@ -281,7 +284,7 @@ func (c *GatewayClient) FilterChunks(ctx context.Context, _ string, interval blo
 		return nil, err
 	}
 
-	buf := make([]*logproto.GroupedChunkRefs, 0, count)
+	buf := make([]*logproto.GroupedChunkRefs, 0, int(count.Load()))
 	return mergeSeries(results, buf)
 }
 

pkg/bloomgateway/metrics.go

@@ -15,21 +15,25 @@ type metrics struct {
 	*serverMetrics
 }
 
+const (
+	typeSuccess = "success"
+	typeError   = "error"
+)
+
 type clientMetrics struct {
-	cacheLocalityScore prometheus.Histogram
-	requestLatency     *prometheus.HistogramVec
-	clients            prometheus.Gauge
+	clientRequests *prometheus.CounterVec
+	requestLatency *prometheus.HistogramVec
+	clients        prometheus.Gauge
 }
 
 func newClientMetrics(registerer prometheus.Registerer) *clientMetrics {
 	return &clientMetrics{
-		cacheLocalityScore: promauto.With(registerer).NewHistogram(prometheus.HistogramOpts{
+		clientRequests: promauto.With(registerer).NewCounterVec(prometheus.CounterOpts{
 			Namespace: constants.Loki,
 			Subsystem: "bloom_gateway_client",
-			Name:      "cache_locality_score",
-			Help:      "Cache locality score of the bloom filter, as measured by % of keyspace touched / % of bloom_gws required",
-			Buckets:   prometheus.LinearBuckets(0.01, 0.2, 5),
-		}),
+			Name:      "requests_total",
+			Help:      "Total number of requests made to the bloom gateway",
+		}, []string{"type"}),
 		requestLatency: promauto.With(registerer).NewHistogramVec(prometheus.HistogramOpts{
 			Namespace: constants.Loki,
 			Subsystem: "bloom_gateway_client",