better inverted index validation

pkg/ingester/index/bitprefix.go

@@ -23,9 +23,16 @@ type BitPrefixInvertedIndex struct {
 	shards      []*indexShard
 }
 
+func ValidateBitPrefixShardFactor(factor uint32) error {
+	if requiredBits := index.NewShard(0, factor).RequiredBits(); 1<<requiredBits != factor {
+		return fmt.Errorf("Incompatible inverted index shard factor on ingester: It must be a power of two, got %d", factor)
+	}
+	return nil
+}
+
 func NewBitPrefixWithShards(totalShards uint32) (*BitPrefixInvertedIndex, error) {
-	if requiredBits := index.NewShard(0, totalShards).RequiredBits(); 1<<requiredBits != totalShards {
-		return nil, fmt.Errorf("Incompatible inverted index shard factor on ingester: It must be a power of two, got %d", totalShards)
+	if err := ValidateBitPrefixShardFactor(totalShards); err != nil {
+		return nil, err
 	}
 
 	shards := make([]*indexShard, totalShards)

pkg/loki/config_compat.go

@@ -0,0 +1,42 @@
+package loki
+
+import (
+	"fmt"
+
+	"github.com/grafana/loki/pkg/ingester/index"
+	"github.com/grafana/loki/pkg/storage/config"
+)
+
+func ValidateConfigCompatibility(c Config) error {
+	for _, fn := range []func(Config) error{
+		ensureInvertedIndexShardingCompatibility,
+	} {
+		if err := fn(c); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func ensureInvertedIndexShardingCompatibility(c Config) error {
+
+	for i, sc := range c.SchemaConfig.Configs {
+		switch sc.IndexType {
+		case config.TSDBType:
+			if err := index.ValidateBitPrefixShardFactor(uint32(c.Ingester.IndexShards)); err != nil {
+				return err
+			}
+		default:
+			if sc.RowShards > 0 && c.Ingester.IndexShards%int(sc.RowShards) > 0 {
+				return fmt.Errorf(
+					"incompatible ingester index shards (%d) and period config row shard factor (%d) for period config at index (%d). The ingester factor must be evenly divisible by all period config factors",
+					c.Ingester.IndexShards,
+					sc.RowShards,
+					i,
+				)
+			}
+		}
+
+	}
+	return nil
+}

pkg/loki/loki.go

@@ -195,19 +195,14 @@ func (c *Config) Validate() error {
 		c.LimitsConfig.MaxQueryLookback = c.ChunkStoreConfig.MaxLookBackPeriod
 	}
 
-	for i, sc := range c.SchemaConfig.Configs {
-		if sc.RowShards > 0 && c.Ingester.IndexShards%int(sc.RowShards) > 0 {
-			return fmt.Errorf(
-				"incompatible ingester index shards (%d) and period config row shard factor (%d) for period config at index (%d). The ingester factor must be evenly divisible by all period config factors",
-				c.Ingester.IndexShards,
-				sc.RowShards,
-				i,
-			)
-		}
-	}
 	if err := c.QueryRange.Validate(); err != nil {
 		return errors.Wrap(err, "invalid query_range config")
 	}
+
+	if err := ValidateConfigCompatibility(*c); err != nil {
+		return err
+	}
+
 	return nil
 }