Bloom-Gateway cache

docs/sources/configure/_index.md

@@ -1838,6 +1838,21 @@ client:
   # CLI flag: -bloom-gateway-client.log-gateway-requests
   [log_gateway_requests: <boolean> | default = false]
 
+  results_cache:
+    # The cache block configures the cache backend.
+    # The CLI flags prefix for this block configuration is:
+    # bloom-gateway-client.cache
+    [cache: <cache_config>]
+
+    # Use compression in cache. The default is an empty value '', which disables
+    # compression. Supported values are: 'snappy' and ''.
+    # CLI flag: -bloom-gateway-client.cache.compression
+    [compression: <string> | default = ""]
+
+  # Flag to control whether to cache bloom gateway client requests/responses.
+  # CLI flag: -bloom-gateway-client.cache_results
+  [cache_results: <boolean> | default = false]
+
 # Number of workers to use for filtering chunks concurrently.
 # CLI flag: -bloom-gateway.worker-concurrency
 [worker_concurrency: <int> | default = 4]
@@ -3028,6 +3043,10 @@ shard_streams:
 # CLI flag: -bloom-gateway.blocks-downloading-parallelism
 [bloom_gateway_blocks_downloading_parallelism: <int> | default = 50]
 
+# Interval for computing the cache key in the Bloom Gateway.
+# CLI flag: -bloom-gateway.cache-key-interval
+[bloom_gateway_cache_key_interval: <duration> | default = 15m]
+
 # Allow user to send structured metadata in push payload.
 # CLI flag: -validation.allow-structured-metadata
 [allow_structured_metadata: <boolean> | default = false]
@@ -4233,6 +4252,7 @@ The TLS configuration.
 
 The cache block configures the cache backend. The supported CLI flags `<prefix>` used to reference this configuration block are:
 
+- `bloom-gateway-client.cache`
 - `frontend`
 - `frontend.index-stats-results-cache`
 - `frontend.volume-results-cache`

pkg/bloomgateway/cache.go

@@ -0,0 +1,217 @@
+package bloomgateway
+
+import (
+	"context"
+	"flag"
+	"sort"
+	"time"
+
+	"github.com/go-kit/log"
+	"github.com/prometheus/common/model"
+	"golang.org/x/exp/slices"
+	"google.golang.org/grpc"
+
+	"github.com/grafana/loki/pkg/logproto"
+	"github.com/grafana/loki/pkg/storage/chunk/cache"
+	"github.com/grafana/loki/pkg/storage/chunk/cache/resultscache"
+)
+
+const (
+	cacheParalellism = 1
+)
+
+type CacheConfig struct {
+	resultscache.Config `yaml:",inline"`
+}
+
+// RegisterFlags registers flags.
+func (cfg *CacheConfig) RegisterFlags(f *flag.FlagSet) {
+	cfg.RegisterFlagsWithPrefix("bloom-gateway-client.cache.", f)
+}
+
+func (cfg *CacheConfig) RegisterFlagsWithPrefix(prefix string, f *flag.FlagSet) {
+	cfg.Config.RegisterFlagsWithPrefix(f, prefix)
+}
+
+type CacheLimits interface {
+	resultscache.Limits
+	BloomGatewayCacheKeyInterval(tenantID string) time.Duration
+}
+
+type keyGen struct {
+	CacheLimits
+}
+
+func newCacheKeyGen(limits CacheLimits) keyGen {
+	return keyGen{limits}
+}
+
+func (k keyGen) GenerateCacheKey(ctx context.Context, tenant string, r resultscache.Request) string {
+	return resultscache.ConstSplitter(k.BloomGatewayCacheKeyInterval(tenant)).GenerateCacheKey(ctx, tenant, r)
+}
+
+type extractor struct{}
+
+func newExtractor() extractor {
+	return extractor{}
+}
+
+// Extract extracts a subset of a response from the `start` and `end` timestamps in milliseconds.
+// We remove chunks that are not within the given time range.
+func (e extractor) Extract(start, end int64, r resultscache.Response, _, _ int64) resultscache.Response {
+	res := r.(*logproto.FilterChunkRefResponse)
+
+	chunkRefs := make([]*logproto.GroupedChunkRefs, 0, len(res.ChunkRefs))
+	for _, chunkRef := range res.ChunkRefs {
+		refs := make([]*logproto.ShortRef, 0, len(chunkRef.Refs))
+		for _, ref := range chunkRef.Refs {
+			if model.Time(end) < ref.From || ref.Through <= model.Time(start) {
+				continue
+			}
+			refs = append(refs, ref)
+		}
+		if len(refs) > 0 {
+			chunkRefs = append(chunkRefs, &logproto.GroupedChunkRefs{
+				Fingerprint: chunkRef.Fingerprint,
+				Tenant:      chunkRef.Tenant,
+				Refs:        refs,
+			})
+		}
+	}
+
+	return &logproto.FilterChunkRefResponse{
+		ChunkRefs: chunkRefs,
+	}
+}
+
+type merger struct{}
+
+func newMerger() merger {
+	return merger{}
+}
+
+// MergeResponse merges responses from multiple requests into a single Response
+// We merge all chunks grouped by their fingerprint.
+func (m merger) MergeResponse(responses ...resultscache.Response) (resultscache.Response, error) {
+	var size int
+	for _, r := range responses {
+		res := r.(*logproto.FilterChunkRefResponse)
+		size += len(res.ChunkRefs)
+	}
+
+	chunkRefs := make([]*logproto.GroupedChunkRefs, 0, size)
+	for _, r := range responses {
+		res := r.(*logproto.FilterChunkRefResponse)
+		chunkRefs = append(chunkRefs, res.ChunkRefs...)
+	}
+
+	return &logproto.FilterChunkRefResponse{
+		ChunkRefs: mergeGroupedChunkRefs(chunkRefs),
+	}, nil
+}
+
+// Merge duplicated fingerprints by:
+// 1. Sort the chunkRefs by their stream fingerprint
+// 2. Remove duplicated FPs appending all chunks into the first fingerprint's chunk list.
+func mergeGroupedChunkRefs(chunkRefs []*logproto.GroupedChunkRefs) []*logproto.GroupedChunkRefs {
+	if len(chunkRefs) <= 1 {
+		return chunkRefs
+	}
+
+	sort.Slice(chunkRefs, func(i, j int) bool {
+		return chunkRefs[i].Fingerprint < chunkRefs[j].Fingerprint
+	})
+
+	var lastDiffFP int
+	for i := 1; i < len(chunkRefs); i++ {
+		if chunkRefs[lastDiffFP].Fingerprint == chunkRefs[i].Fingerprint {
+			chunkRefs[lastDiffFP].Refs = mergeShortRefs(append(chunkRefs[lastDiffFP].Refs, chunkRefs[i].Refs...))
+		} else {
+			lastDiffFP++
+			chunkRefs[lastDiffFP] = chunkRefs[i]
+		}
+	}
+	return chunkRefs[:lastDiffFP+1]
+}
+
+// mergeShortRefs merges short-refs by removing duplicated checksums.
+func mergeShortRefs(refs []*logproto.ShortRef) []*logproto.ShortRef {
+	if len(refs) <= 1 {
+		return refs
+	}
+
+	sort.Slice(refs, func(i, j int) bool {
+		return refs[i].Checksum < refs[j].Checksum
+	})
+	return slices.CompactFunc(refs, func(a, b *logproto.ShortRef) bool {
+		return a.Checksum == b.Checksum
+	})
+}
+
+type ClientCache struct {
+	cache  *resultscache.ResultsCache
+	limits CacheLimits
+	logger log.Logger
+}
+
+func NewBloomGatewayClientCacheMiddleware(
+	logger log.Logger,
+	next logproto.BloomGatewayClient,
+	c cache.Cache,
+	limits CacheLimits,
+	cacheGen resultscache.CacheGenNumberLoader,
+	retentionEnabled bool,
+) *ClientCache {
+	nextAsHandler := resultscache.HandlerFunc(func(ctx context.Context, cacheReq resultscache.Request) (resultscache.Response, error) {
+		req := cacheReq.(requestWithGrpcCallOptions)
+		return next.FilterChunkRefs(ctx, req.FilterChunkRefRequest, req.grpcCallOptions...)
+	})
+
+	resultsCache := resultscache.NewResultsCache(
+		logger,
+		c,
+		nextAsHandler,
+		newCacheKeyGen(limits),
+		limits,
+		newMerger(),
+		newExtractor(),
+		nil,
+		nil,
+		func(_ context.Context, _ []string, _ resultscache.Request) int {
+			return cacheParalellism
+		},
+		cacheGen,
+		retentionEnabled,
+	)
+
+	return &ClientCache{
+		cache:  resultsCache,
+		limits: limits,
+		logger: logger,
+	}
+}
+
+func (c *ClientCache) FilterChunkRefs(ctx context.Context, req *logproto.FilterChunkRefRequest, opts ...grpc.CallOption) (*logproto.FilterChunkRefResponse, error) {
+	cacheReq := requestWithGrpcCallOptions{
+		FilterChunkRefRequest: req,
+		grpcCallOptions:       opts,
+	}
+	res, err := c.cache.Do(ctx, cacheReq)
+	if err != nil {
+		return nil, err
+	}
+
+	return res.(*logproto.FilterChunkRefResponse), nil
+}
+
+type requestWithGrpcCallOptions struct {
+	*logproto.FilterChunkRefRequest
+	grpcCallOptions []grpc.CallOption
+}
+
+func (r requestWithGrpcCallOptions) WithStartEndForCache(start time.Time, end time.Time) resultscache.Request {
+	return requestWithGrpcCallOptions{
+		FilterChunkRefRequest: r.FilterChunkRefRequest.WithStartEndForCache(start, end).(*logproto.FilterChunkRefRequest),
+		grpcCallOptions:       r.grpcCallOptions,
+	}
+}