less opaque chunk keys on fs with v12

pkg/storage/chunk/local/fixtures.go

@@ -43,7 +43,7 @@ func (f *fixture) Clients() (
 		return
 	}
 
-	chunkClient = objectclient.NewClient(oClient, objectclient.Base64Encoder, chunk.SchemaConfig{})
+	chunkClient = objectclient.NewClient(oClient, objectclient.FSEncoder, chunk.SchemaConfig{})
 
 	tableClient, err = NewTableClient(f.dirname)
 	if err != nil {

pkg/storage/chunk/objectclient/client.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/base64"
+	"strings"
 
 	"github.com/pkg/errors"
 
@@ -13,14 +14,30 @@ import (
 
 // KeyEncoder is used to encode chunk keys before writing/retrieving chunks
 // from the underlying ObjectClient
-type KeyEncoder func(string) string
+// Schema/Chunk are passed as arguments to allow this to improve over revisions
+type KeyEncoder func(schema chunk.SchemaConfig, chk chunk.Chunk) string
 
-// Base64Encoder is used to encode chunk keys in base64 before storing/retrieving
+// base64Encoder is used to encode chunk keys in base64 before storing/retrieving
 // them from the ObjectClient
-var Base64Encoder = func(key string) string {
+var base64Encoder = func(key string) string {
 	return base64.StdEncoding.EncodeToString([]byte(key))
 }
 
+var FSEncoder = func(schema chunk.SchemaConfig, chk chunk.Chunk) string {
+	// Filesystem encoder pre-v12 encodes the chunk as one base64 string.
+	// This has the downside of making them opaque and storing all chunks in a single
+	// directory, hurting performance at scale and discoverability.
+	// Post v12, we respect the directory structure imposed by chunk keys.
+	key := schema.ExternalKey(chk)
+	if schema.VersionForChunk(chk) > 11 {
+		split := strings.LastIndexByte(key, '/')
+		encodedTail := base64Encoder(key[split+1:])
+		return strings.Join([]string{key[:split], encodedTail}, "/")
+
+	}
+	return base64Encoder(key)
+}
+
 const defaultMaxParallel = 150
 
 // Client is used to store chunks in object store backends
@@ -56,7 +73,6 @@ func (o *Client) PutChunks(ctx context.Context, chunks []chunk.Chunk) error {
 	var (
 		chunkKeys []string
 		chunkBufs [][]byte
-		key       string
 	)
 
 	for i := range chunks {
@@ -65,10 +81,11 @@ func (o *Client) PutChunks(ctx context.Context, chunks []chunk.Chunk) error {
 			return err
 		}
 
-		key = o.schema.ExternalKey(chunks[i])
-
+		var key string
 		if o.keyEncoder != nil {
-			key = o.keyEncoder(key)
+			key = o.keyEncoder(o.schema, chunks[i])
+		} else {
+			key = o.schema.ExternalKey(chunks[i])
 		}
 
 		chunkKeys = append(chunkKeys, key)
@@ -109,7 +126,7 @@ func (o *Client) getChunk(ctx context.Context, decodeContext *chunk.DecodeContex
 
 	key := o.schema.ExternalKey(c)
 	if o.keyEncoder != nil {
-		key = o.keyEncoder(key)
+		key = o.keyEncoder(o.schema, c)
 	}
 
 	readCloser, size, err := o.store.GetObject(ctx, key)
@@ -137,7 +154,11 @@ func (o *Client) getChunk(ctx context.Context, decodeContext *chunk.DecodeContex
 func (o *Client) DeleteChunk(ctx context.Context, userID, chunkID string) error {
 	key := chunkID
 	if o.keyEncoder != nil {
-		key = o.keyEncoder(key)
+		c, err := chunk.ParseExternalKey(userID, key)
+		if err != nil {
+			return err
+		}
+		key = o.keyEncoder(o.schema, c)
 	}
 	return o.store.DeleteObject(ctx, key)
 }

pkg/storage/chunk/objectclient/client_test.go

@@ -0,0 +1,79 @@
+package objectclient
+
+import (
+	"testing"
+	"time"
+
+	"github.com/prometheus/common/model"
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/loki/pkg/storage/chunk"
+)
+
+func MustParseDayTime(s string) chunk.DayTime {
+	t, err := time.Parse("2006-01-02", s)
+	if err != nil {
+		panic(err)
+	}
+	return chunk.DayTime{
+		Time: model.TimeFromUnix(t.Unix()),
+	}
+}
+
+func TestFSEncoder(t *testing.T) {
+	schema := chunk.SchemaConfig{
+		Configs: []chunk.PeriodConfig{
+			{
+				From:   MustParseDayTime("2020-01-01"),
+				Schema: "v11",
+			},
+			{
+				From:   MustParseDayTime("2022-01-01"),
+				Schema: "v12",
+			},
+		},
+	}
+
+	// chunk that resolves to v11
+	oldChunk := chunk.Chunk{
+		UserID:      "fake",
+		From:        MustParseDayTime("2020-01-02").Time,
+		Through:     MustParseDayTime("2020-01-03").Time,
+		Checksum:    123,
+		Fingerprint: 456,
+		ChecksumSet: true,
+	}
+
+	// chunk that resolves to v12
+	newChunk := chunk.Chunk{
+		UserID:      "fake",
+		From:        MustParseDayTime("2022-01-02").Time,
+		Through:     MustParseDayTime("2022-01-03").Time,
+		Checksum:    123,
+		Fingerprint: 456,
+		ChecksumSet: true,
+	}
+
+	for _, tc := range []struct {
+		desc string
+		from string
+		exp  string
+	}{
+		{
+			desc: "before v12 encodes entire chunk",
+			from: schema.ExternalKey(oldChunk),
+			exp:  "ZmFrZS8xYzg6MTZmNjM4ZDQ0MDA6MTZmNjhiM2EwMDA6N2I=",
+		},
+		{
+			desc: "v12+ encodes encodes the non-directory trail",
+			from: schema.ExternalKey(newChunk),
+			exp:  "fake/1c8/MTdlMTgxNWY4MDA6MTdlMWQzYzU0MDA6N2I=",
+		},
+	} {
+		t.Run(tc.desc, func(t *testing.T) {
+			chk, err := chunk.ParseExternalKey("fake", tc.from)
+			require.Nil(t, err)
+			require.Equal(t, tc.exp, FSEncoder(schema, chk))
+		})
+	}
+}

pkg/storage/chunk/schema_config.go

@@ -504,6 +504,14 @@ func (cfg SchemaConfig) ExternalKey(chunk Chunk) string {
 	}
 }
 
+// VersionForChunk will return the schema version associated with the `From` timestamp of a chunk.
+// The schema and chunk must be valid+compatible as the errors are not checked.
+func (cfg SchemaConfig) VersionForChunk(c Chunk) int {
+	p, _ := cfg.SchemaForTime(c.From)
+	v, _ := p.VersionAsInt()
+	return v
+}
+
 // pre-checksum
 func (cfg SchemaConfig) legacyExternalKey(chunk Chunk) string {
 	// This is the inverse of chunk.parseLegacyExternalKey, with "<user id>/" prepended.

pkg/storage/chunk/storage/factory.go

@@ -330,7 +330,7 @@ func NewChunkClient(name string, cfg Config, schemaCfg chunk.SchemaConfig, clien
 		if err != nil {
 			return nil, err
 		}
-		return objectclient.NewClientWithMaxParallel(store, objectclient.Base64Encoder, cfg.MaxParallelGetChunk, schemaCfg), nil
+		return objectclient.NewClientWithMaxParallel(store, objectclient.FSEncoder, cfg.MaxParallelGetChunk, schemaCfg), nil
 	case StorageTypeGrpc:
 		return grpc.NewStorageClient(cfg.GrpcConfig, schemaCfg)
 	default:

pkg/storage/stores/shipper/compactor/compactor.go

@@ -191,7 +191,7 @@ func (c *Compactor) init(storageConfig storage.Config, schemaConfig loki_storage
 	if c.cfg.RetentionEnabled {
 		var encoder objectclient.KeyEncoder
 		if _, ok := objectClient.(*local.FSObjectClient); ok {
-			encoder = objectclient.Base64Encoder
+			encoder = objectclient.FSEncoder
 		}
 
 		chunkClient := objectclient.NewClient(objectClient, encoder, schemaConfig.SchemaConfig)

pkg/storage/stores/shipper/compactor/retention/retention_test.go

@@ -389,7 +389,7 @@ func TestChunkRewriter(t *testing.T) {
 			require.NoError(t, store.Put(context.TODO(), []chunk.Chunk{tt.chunk}))
 			store.Stop()
 
-			chunkClient := objectclient.NewClient(newTestObjectClient(store.chunkDir, cm), objectclient.Base64Encoder, schemaCfg.SchemaConfig)
+			chunkClient := objectclient.NewClient(newTestObjectClient(store.chunkDir, cm), objectclient.FSEncoder, schemaCfg.SchemaConfig)
 			for _, indexTable := range store.indexTables() {
 				err := indexTable.DB.Update(func(tx *bbolt.Tx) error {
 					bucket := tx.Bucket(local.IndexBucketName)
@@ -668,7 +668,7 @@ func TestMarkForDelete_SeriesCleanup(t *testing.T) {
 			tables := store.indexTables()
 			require.Len(t, tables, len(tc.expectedDeletedSeries))
 
-			chunkClient := objectclient.NewClient(newTestObjectClient(store.chunkDir, cm), objectclient.Base64Encoder, schemaCfg.SchemaConfig)
+			chunkClient := objectclient.NewClient(newTestObjectClient(store.chunkDir, cm), objectclient.FSEncoder, schemaCfg.SchemaConfig)
 
 			for i, table := range tables {
 				seriesCleanRecorder := newSeriesCleanRecorder()