config.go

package tsdb

import (
	"flag"
	"path/filepath"
	"strings"
	"time"

	"github.com/alecthomas/units"
	"github.com/pkg/errors"
	"github.com/prometheus/prometheus/tsdb"
	"github.com/prometheus/prometheus/tsdb/chunks"
	"github.com/prometheus/prometheus/tsdb/wlog"
	"github.com/thanos-io/thanos/pkg/store"

	"github.com/cortexproject/cortex/pkg/storage/bucket"
	"github.com/cortexproject/cortex/pkg/util"
)

const (
	// TenantIDExternalLabel is the external label containing the tenant ID,
	// set when shipping blocks to the storage.
	TenantIDExternalLabel = "__org_id__"

	// IngesterIDExternalLabel is the external label containing the ingester ID,
	// set when shipping blocks to the storage.
	IngesterIDExternalLabel = "__ingester_id__"

	// How often are open TSDBs checked for being idle and closed.
	DefaultCloseIdleTSDBInterval = 5 * time.Minute

	// How often to check for tenant deletion mark.
	DeletionMarkCheckInterval = 1 * time.Hour

	// Default minimum bucket size (bytes) of the chunk pool.
	ChunkPoolDefaultMinBucketSize = store.EstimatedMaxChunkSize

	// Default maximum bucket size (bytes) of the chunk pool.
	ChunkPoolDefaultMaxBucketSize = 50e6
)

// Validation errors
var (
	errInvalidShipConcurrency       = errors.New("invalid TSDB ship concurrency")
	errInvalidOpeningConcurrency    = errors.New("invalid TSDB opening concurrency")
	errInvalidCompactionInterval    = errors.New("invalid TSDB compaction interval")
	errInvalidCompactionConcurrency = errors.New("invalid TSDB compaction concurrency")
	errInvalidWALSegmentSizeBytes   = errors.New("invalid TSDB WAL segment size bytes")
	errInvalidStripeSize            = errors.New("invalid TSDB stripe size")
	errInvalidOutOfOrderCapMax      = errors.New("invalid TSDB OOO chunks capacity (in samples)")
	errEmptyBlockranges             = errors.New("empty block ranges for TSDB")

	ErrInvalidBucketIndexBlockDiscoveryStrategy = errors.New("bucket index block discovery strategy can only be enabled when bucket index is enabled")
	ErrBlockDiscoveryStrategy                   = errors.New("invalid block discovery strategy")
)

// BlocksStorageConfig holds the config information for the blocks storage.
//
//nolint:revive
type BlocksStorageConfig struct {
	Bucket      bucket.Config     `yaml:",inline"`
	BucketStore BucketStoreConfig `yaml:"bucket_store" doc:"description=This configures how the querier and store-gateway discover and synchronize blocks stored in the bucket."`
	TSDB        TSDBConfig        `yaml:"tsdb"`
}

// DurationList is the block ranges for a tsdb
type DurationList []time.Duration

// String implements the flag.Value interface
func (d *DurationList) String() string {
	values := make([]string, 0, len(*d))
	for _, v := range *d {
		values = append(values, v.String())
	}

	return strings.Join(values, ",")
}

// Set implements the flag.Value interface
func (d *DurationList) Set(s string) error {
	values := strings.Split(s, ",")
	*d = make([]time.Duration, 0, len(values)) // flag.Parse may be called twice, so overwrite instead of append
	for _, v := range values {
		t, err := time.ParseDuration(v)
		if err != nil {
			return err
		}
		*d = append(*d, t)
	}
	return nil
}

// ToMilliseconds returns the duration list in milliseconds
func (d *DurationList) ToMilliseconds() []int64 {
	values := make([]int64, 0, len(*d))
	for _, t := range *d {
		values = append(values, t.Milliseconds())
	}

	return values
}

// RegisterFlags registers the TSDB flags
func (cfg *BlocksStorageConfig) RegisterFlags(f *flag.FlagSet) {
	cfg.Bucket.RegisterFlagsWithPrefix("blocks-storage.", f)
	cfg.BucketStore.RegisterFlags(f)
	cfg.TSDB.RegisterFlags(f)
}

// Validate the config.
func (cfg *BlocksStorageConfig) Validate() error {
	if err := cfg.Bucket.Validate(); err != nil {
		return err
	}

	if err := cfg.TSDB.Validate(); err != nil {
		return err
	}

	return cfg.BucketStore.Validate()
}

// TSDBConfig holds the config for TSDB opened in the ingesters.
//
//nolint:revive
type TSDBConfig struct {
	Dir                       string        `yaml:"dir"`
	BlockRanges               DurationList  `yaml:"block_ranges_period"`
	Retention                 time.Duration `yaml:"retention_period"`
	ShipInterval              time.Duration `yaml:"ship_interval"`
	ShipConcurrency           int           `yaml:"ship_concurrency"`
	HeadCompactionInterval    time.Duration `yaml:"head_compaction_interval"`
	HeadCompactionConcurrency int           `yaml:"head_compaction_concurrency"`
	HeadCompactionIdleTimeout time.Duration `yaml:"head_compaction_idle_timeout"`
	HeadChunksWriteBufferSize int           `yaml:"head_chunks_write_buffer_size_bytes"`
	StripeSize                int           `yaml:"stripe_size"`
	WALCompressionEnabled     bool          `yaml:"wal_compression_enabled"`
	WALSegmentSizeBytes       int           `yaml:"wal_segment_size_bytes"`
	FlushBlocksOnShutdown     bool          `yaml:"flush_blocks_on_shutdown"`
	CloseIdleTSDBTimeout      time.Duration `yaml:"close_idle_tsdb_timeout"`
	// The size of the in-memory queue used before flushing chunks to the disk.
	HeadChunksWriteQueueSize int `yaml:"head_chunks_write_queue_size"`

	// MaxTSDBOpeningConcurrencyOnStartup limits the number of concurrently opening TSDB's during startup.
	MaxTSDBOpeningConcurrencyOnStartup int `yaml:"max_tsdb_opening_concurrency_on_startup"`

	// If true, user TSDBs are not closed on shutdown. Only for testing.
	// If false (default), user TSDBs are closed to make sure all resources are released and closed properly.
	KeepUserTSDBOpenOnShutdown bool `yaml:"-"`

	// How often to check for idle TSDBs for closing. DefaultCloseIdleTSDBInterval is not suitable for testing, so tests can override.
	CloseIdleTSDBInterval time.Duration `yaml:"-"`

	// Positive value enables experimental support for exemplars. 0 or less to disable.
	MaxExemplars int `yaml:"max_exemplars"`

	// Enable snapshotting of in-memory TSDB data on disk when shutting down.
	MemorySnapshotOnShutdown bool `yaml:"memory_snapshot_on_shutdown"`

	// OutOfOrderCapMax is maximum capacity for OOO chunks (in samples).
	OutOfOrderCapMax int64 `yaml:"out_of_order_cap_max"`
}

// RegisterFlags registers the TSDBConfig flags.
func (cfg *TSDBConfig) RegisterFlags(f *flag.FlagSet) {
	if len(cfg.BlockRanges) == 0 {
		cfg.BlockRanges = []time.Duration{2 * time.Hour} // Default 2h block
	}

	f.StringVar(&cfg.Dir, "blocks-storage.tsdb.dir", "tsdb", "Local directory to store TSDBs in the ingesters.")
	f.Var(&cfg.BlockRanges, "blocks-storage.tsdb.block-ranges-period", "TSDB blocks range period.")
	f.DurationVar(&cfg.Retention, "blocks-storage.tsdb.retention-period", 6*time.Hour, "TSDB blocks retention in the ingester before a block is removed. This should be larger than the block_ranges_period and large enough to give store-gateways and queriers enough time to discover newly uploaded blocks.")
	f.DurationVar(&cfg.ShipInterval, "blocks-storage.tsdb.ship-interval", 1*time.Minute, "How frequently the TSDB blocks are scanned and new ones are shipped to the storage. 0 means shipping is disabled.")
	f.IntVar(&cfg.ShipConcurrency, "blocks-storage.tsdb.ship-concurrency", 10, "Maximum number of tenants concurrently shipping blocks to the storage.")
	f.IntVar(&cfg.MaxTSDBOpeningConcurrencyOnStartup, "blocks-storage.tsdb.max-tsdb-opening-concurrency-on-startup", 10, "limit the number of concurrently opening TSDB's on startup")
	f.DurationVar(&cfg.HeadCompactionInterval, "blocks-storage.tsdb.head-compaction-interval", 1*time.Minute, "How frequently does Cortex try to compact TSDB head. Block is only created if data covers smallest block range. Must be greater than 0 and max 5 minutes.")
	f.IntVar(&cfg.HeadCompactionConcurrency, "blocks-storage.tsdb.head-compaction-concurrency", 5, "Maximum number of tenants concurrently compacting TSDB head into a new block")
	f.DurationVar(&cfg.HeadCompactionIdleTimeout, "blocks-storage.tsdb.head-compaction-idle-timeout", 1*time.Hour, "If TSDB head is idle for this duration, it is compacted. Note that up to 25% jitter is added to the value to avoid ingesters compacting concurrently. 0 means disabled.")
	f.IntVar(&cfg.HeadChunksWriteBufferSize, "blocks-storage.tsdb.head-chunks-write-buffer-size-bytes", chunks.DefaultWriteBufferSize, "The write buffer size used by the head chunks mapper. Lower values reduce memory utilisation on clusters with a large number of tenants at the cost of increased disk I/O operations.")
	f.IntVar(&cfg.StripeSize, "blocks-storage.tsdb.stripe-size", 16384, "The number of shards of series to use in TSDB (must be a power of 2). Reducing this will decrease memory footprint, but can negatively impact performance.")
	f.BoolVar(&cfg.WALCompressionEnabled, "blocks-storage.tsdb.wal-compression-enabled", false, "True to enable TSDB WAL compression.")
	f.IntVar(&cfg.WALSegmentSizeBytes, "blocks-storage.tsdb.wal-segment-size-bytes", wlog.DefaultSegmentSize, "TSDB WAL segments files max size (bytes).")
	f.BoolVar(&cfg.FlushBlocksOnShutdown, "blocks-storage.tsdb.flush-blocks-on-shutdown", false, "True to flush blocks to storage on shutdown. If false, incomplete blocks will be reused after restart.")
	f.DurationVar(&cfg.CloseIdleTSDBTimeout, "blocks-storage.tsdb.close-idle-tsdb-timeout", 0, "If TSDB has not received any data for this duration, and all blocks from TSDB have been shipped, TSDB is closed and deleted from local disk. If set to positive value, this value should be equal or higher than -querier.query-ingesters-within flag to make sure that TSDB is not closed prematurely, which could cause partial query results. 0 or negative value disables closing of idle TSDB.")
	f.IntVar(&cfg.HeadChunksWriteQueueSize, "blocks-storage.tsdb.head-chunks-write-queue-size", chunks.DefaultWriteQueueSize, "The size of the in-memory queue used before flushing chunks to the disk.")
	f.IntVar(&cfg.MaxExemplars, "blocks-storage.tsdb.max-exemplars", 0, "Deprecated, use maxExemplars in limits instead. If the MaxExemplars value in limits is set to zero, cortex will fallback on this value. This setting enables support for exemplars in TSDB and sets the maximum number that will be stored. 0 or less means disabled.")
	f.BoolVar(&cfg.MemorySnapshotOnShutdown, "blocks-storage.tsdb.memory-snapshot-on-shutdown", false, "True to enable snapshotting of in-memory TSDB data on disk when shutting down.")
	f.Int64Var(&cfg.OutOfOrderCapMax, "blocks-storage.tsdb.out-of-order-cap-max", tsdb.DefaultOutOfOrderCapMax, "[EXPERIMENTAL] Configures the maximum number of samples per chunk that can be out-of-order.")
}

// Validate the config.
func (cfg *TSDBConfig) Validate() error {
	if cfg.ShipInterval > 0 && cfg.ShipConcurrency <= 0 {
		return errInvalidShipConcurrency
	}

	if cfg.MaxTSDBOpeningConcurrencyOnStartup <= 0 {
		return errInvalidOpeningConcurrency
	}

	if cfg.HeadCompactionInterval <= 0 || cfg.HeadCompactionInterval > 5*time.Minute {
		return errInvalidCompactionInterval
	}

	if cfg.HeadCompactionConcurrency <= 0 {
		return errInvalidCompactionConcurrency
	}

	if cfg.HeadChunksWriteBufferSize < chunks.MinWriteBufferSize || cfg.HeadChunksWriteBufferSize > chunks.MaxWriteBufferSize || cfg.HeadChunksWriteBufferSize%1024 != 0 {
		return errors.Errorf("head chunks write buffer size must be a multiple of 1024 between %d and %d", chunks.MinWriteBufferSize, chunks.MaxWriteBufferSize)
	}

	if cfg.StripeSize <= 1 || (cfg.StripeSize&(cfg.StripeSize-1)) != 0 { // ensure stripe size is a positive power of 2
		return errInvalidStripeSize
	}

	if len(cfg.BlockRanges) == 0 {
		return errEmptyBlockranges
	}

	if cfg.WALSegmentSizeBytes <= 0 {
		return errInvalidWALSegmentSizeBytes
	}

	if cfg.OutOfOrderCapMax <= 0 {
		return errInvalidOutOfOrderCapMax
	}

	return nil
}

// BlocksDir returns the directory path where TSDB blocks and wal should be
// stored by the ingester
func (cfg *TSDBConfig) BlocksDir(userID string) string {
	return filepath.Join(cfg.Dir, userID)
}

// IsBlocksShippingEnabled returns whether blocks shipping is enabled.
func (cfg *TSDBConfig) IsBlocksShippingEnabled() bool {
	return cfg.ShipInterval > 0
}

// BucketStoreConfig holds the config information for Bucket Stores used by the querier and store-gateway.
type BucketStoreConfig struct {
	SyncDir                  string              `yaml:"sync_dir"`
	SyncInterval             time.Duration       `yaml:"sync_interval"`
	MaxConcurrent            int                 `yaml:"max_concurrent"`
	MaxInflightRequests      int                 `yaml:"max_inflight_requests"`
	TenantSyncConcurrency    int                 `yaml:"tenant_sync_concurrency"`
	BlockSyncConcurrency     int                 `yaml:"block_sync_concurrency"`
	MetaSyncConcurrency      int                 `yaml:"meta_sync_concurrency"`
	ConsistencyDelay         time.Duration       `yaml:"consistency_delay"`
	IndexCache               IndexCacheConfig    `yaml:"index_cache"`
	ChunksCache              ChunksCacheConfig   `yaml:"chunks_cache"`
	MetadataCache            MetadataCacheConfig `yaml:"metadata_cache"`
	IgnoreDeletionMarksDelay time.Duration       `yaml:"ignore_deletion_mark_delay"`
	IgnoreBlocksWithin       time.Duration       `yaml:"ignore_blocks_within"`
	BucketIndex              BucketIndexConfig   `yaml:"bucket_index"`
	BlockDiscoveryStrategy   string              `yaml:"block_discovery_strategy"`

	// Chunk pool.
	MaxChunkPoolBytes           uint64 `yaml:"max_chunk_pool_bytes"`
	ChunkPoolMinBucketSizeBytes int    `yaml:"chunk_pool_min_bucket_size_bytes" doc:"hidden"`
	ChunkPoolMaxBucketSizeBytes int    `yaml:"chunk_pool_max_bucket_size_bytes" doc:"hidden"`

	// Controls whether index-header lazy loading is enabled.
	IndexHeaderLazyLoadingEnabled     bool          `yaml:"index_header_lazy_loading_enabled"`
	IndexHeaderLazyLoadingIdleTimeout time.Duration `yaml:"index_header_lazy_loading_idle_timeout"`

	// Controls whether lazy expanded posting optimization is enabled or not.
	LazyExpandedPostingsEnabled bool `yaml:"lazy_expanded_postings_enabled"`

	// Controls the partitioner, used to aggregate multiple GET object API requests.
	// The config option is hidden until experimental.
	PartitionerMaxGapBytes uint64 `yaml:"partitioner_max_gap_bytes" doc:"hidden"`

	// Controls the estimated size to fetch for series and chunk in Store Gateway. Using
	// a large value might cause data overfetch while a small value might need to refetch.
	EstimatedMaxSeriesSizeBytes uint64 `yaml:"estimated_max_series_size_bytes" doc:"hidden"`
	EstimatedMaxChunkSizeBytes  uint64 `yaml:"estimated_max_chunk_size_bytes" doc:"hidden"`

	// Controls what is the ratio of postings offsets store will hold in memory.
	// Larger value will keep less offsets, which will increase CPU cycles needed for query touching those postings.
	// It's meant for setups that want low baseline memory pressure and where less traffic is expected.
	// On the contrary, smaller value will increase baseline memory usage, but improve latency slightly.
	// 1 will keep all in memory. Default value is the same as in Prometheus which gives a good balance.
	PostingOffsetsInMemSampling int `yaml:"postings_offsets_in_mem_sampling" doc:"hidden"`

	// Controls how many series to fetch per batch in Store Gateway. Default value is 10000.
	SeriesBatchSize int `yaml:"series_batch_size"`
}

// RegisterFlags registers the BucketStore flags
func (cfg *BucketStoreConfig) RegisterFlags(f *flag.FlagSet) {
	cfg.IndexCache.RegisterFlagsWithPrefix(f, "blocks-storage.bucket-store.index-cache.")
	cfg.ChunksCache.RegisterFlagsWithPrefix(f, "blocks-storage.bucket-store.chunks-cache.")
	cfg.MetadataCache.RegisterFlagsWithPrefix(f, "blocks-storage.bucket-store.metadata-cache.")
	cfg.BucketIndex.RegisterFlagsWithPrefix(f, "blocks-storage.bucket-store.bucket-index.")

	f.StringVar(&cfg.SyncDir, "blocks-storage.bucket-store.sync-dir", "tsdb-sync", "Directory to store synchronized TSDB index headers.")
	f.DurationVar(&cfg.SyncInterval, "blocks-storage.bucket-store.sync-interval", 15*time.Minute, "How frequently to scan the bucket, or to refresh the bucket index (if enabled), in order to look for changes (new blocks shipped by ingesters and blocks deleted by retention or compaction).")
	f.Uint64Var(&cfg.MaxChunkPoolBytes, "blocks-storage.bucket-store.max-chunk-pool-bytes", uint64(2*units.Gibibyte), "Max size - in bytes - of a chunks pool, used to reduce memory allocations. The pool is shared across all tenants. 0 to disable the limit.")
	f.IntVar(&cfg.ChunkPoolMinBucketSizeBytes, "blocks-storage.bucket-store.chunk-pool-min-bucket-size-bytes", ChunkPoolDefaultMinBucketSize, "Size - in bytes - of the smallest chunks pool bucket.")
	f.IntVar(&cfg.ChunkPoolMaxBucketSizeBytes, "blocks-storage.bucket-store.chunk-pool-max-bucket-size-bytes", ChunkPoolDefaultMaxBucketSize, "Size - in bytes - of the largest chunks pool bucket.")
	f.IntVar(&cfg.MaxConcurrent, "blocks-storage.bucket-store.max-concurrent", 100, "Max number of concurrent queries to execute against the long-term storage. The limit is shared across all tenants.")
	f.IntVar(&cfg.MaxInflightRequests, "blocks-storage.bucket-store.max-inflight-requests", 0, "Max number of inflight queries to execute against the long-term storage. The limit is shared across all tenants. 0 to disable.")
	f.IntVar(&cfg.TenantSyncConcurrency, "blocks-storage.bucket-store.tenant-sync-concurrency", 10, "Maximum number of concurrent tenants syncing blocks.")
	f.IntVar(&cfg.BlockSyncConcurrency, "blocks-storage.bucket-store.block-sync-concurrency", 20, "Maximum number of concurrent blocks syncing per tenant.")
	f.IntVar(&cfg.MetaSyncConcurrency, "blocks-storage.bucket-store.meta-sync-concurrency", 20, "Number of Go routines to use when syncing block meta files from object storage per tenant.")
	f.DurationVar(&cfg.ConsistencyDelay, "blocks-storage.bucket-store.consistency-delay", 0, "Minimum age of a block before it's being read. Set it to safe value (e.g 30m) if your object storage is eventually consistent. GCS and S3 are (roughly) strongly consistent.")
	f.DurationVar(&cfg.IgnoreDeletionMarksDelay, "blocks-storage.bucket-store.ignore-deletion-marks-delay", time.Hour*6, "Duration after which the blocks marked for deletion will be filtered out while fetching blocks. "+
		"The idea of ignore-deletion-marks-delay is to ignore blocks that are marked for deletion with some delay. This ensures store can still serve blocks that are meant to be deleted but do not have a replacement yet. "+
		"Default is 6h, half of the default value for -compactor.deletion-delay.")
	f.DurationVar(&cfg.IgnoreBlocksWithin, "blocks-storage.bucket-store.ignore-blocks-within", 0, "The blocks created since `now() - ignore_blocks_within` will not be synced. This should be used together with `-querier.query-store-after` to filter out the blocks that are too new to be queried. A reasonable value for this flag would be `-querier.query-store-after - blocks-storage.bucket-store.bucket-index.max-stale-period` to give some buffer. 0 to disable.")
	f.IntVar(&cfg.PostingOffsetsInMemSampling, "blocks-storage.bucket-store.posting-offsets-in-mem-sampling", store.DefaultPostingOffsetInMemorySampling, "Controls what is the ratio of postings offsets that the store will hold in memory.")
	f.BoolVar(&cfg.IndexHeaderLazyLoadingEnabled, "blocks-storage.bucket-store.index-header-lazy-loading-enabled", false, "If enabled, store-gateway will lazily memory-map an index-header only once required by a query.")
	f.DurationVar(&cfg.IndexHeaderLazyLoadingIdleTimeout, "blocks-storage.bucket-store.index-header-lazy-loading-idle-timeout", 20*time.Minute, "If index-header lazy loading is enabled and this setting is > 0, the store-gateway will release memory-mapped index-headers after 'idle timeout' inactivity.")
	f.Uint64Var(&cfg.PartitionerMaxGapBytes, "blocks-storage.bucket-store.partitioner-max-gap-bytes", store.PartitionerMaxGapSize, "Max size - in bytes - of a gap for which the partitioner aggregates together two bucket GET object requests.")
	f.Uint64Var(&cfg.EstimatedMaxSeriesSizeBytes, "blocks-storage.bucket-store.estimated-max-series-size-bytes", store.EstimatedMaxSeriesSize, "Estimated max series size in bytes. Setting a large value might result in over fetching data while a small value might result in data refetch. Default value is 64KB.")
	f.Uint64Var(&cfg.EstimatedMaxChunkSizeBytes, "blocks-storage.bucket-store.estimated-max-chunk-size-bytes", store.EstimatedMaxChunkSize, "Estimated max chunk size in bytes. Setting a large value might result in over fetching data while a small value might result in data refetch. Default value is 16KiB.")
	f.BoolVar(&cfg.LazyExpandedPostingsEnabled, "blocks-storage.bucket-store.lazy-expanded-postings-enabled", false, "If true, Store Gateway will estimate postings size and try to lazily expand postings if it downloads less data than expanding all postings.")
	f.IntVar(&cfg.SeriesBatchSize, "blocks-storage.bucket-store.series-batch-size", store.SeriesBatchSize, "Controls how many series to fetch per batch in Store Gateway. Default value is 10000.")
	f.StringVar(&cfg.BlockDiscoveryStrategy, "blocks-storage.bucket-store.block-discovery-strategy", string(ConcurrentDiscovery), "One of "+strings.Join(supportedBlockDiscoveryStrategies, ", ")+". When set to concurrent, stores will concurrently issue one call per directory to discover active blocks in the bucket. The recursive strategy iterates through all objects in the bucket, recursively traversing into each directory. This avoids N+1 calls at the expense of having slower bucket iterations. bucket_index strategy can be used in Compactor only and utilizes the existing bucket index to fetch block IDs to sync. This avoids iterating the bucket but can be impacted by delays of cleaner creating bucket index.")
}

// Validate the config.
func (cfg *BucketStoreConfig) Validate() error {
	err := cfg.IndexCache.Validate()
	if err != nil {
		return errors.Wrap(err, "index-cache configuration")
	}
	err = cfg.ChunksCache.Validate()
	if err != nil {
		return errors.Wrap(err, "chunks-cache configuration")
	}
	err = cfg.MetadataCache.Validate()
	if err != nil {
		return errors.Wrap(err, "metadata-cache configuration")
	}
	if !util.StringsContain(supportedBlockDiscoveryStrategies, cfg.BlockDiscoveryStrategy) {
		return ErrInvalidBucketIndexBlockDiscoveryStrategy
	}
	return nil
}

type BucketIndexConfig struct {
	Enabled               bool          `yaml:"enabled"`
	UpdateOnErrorInterval time.Duration `yaml:"update_on_error_interval"`
	IdleTimeout           time.Duration `yaml:"idle_timeout"`
	MaxStalePeriod        time.Duration `yaml:"max_stale_period"`
}

func (cfg *BucketIndexConfig) RegisterFlagsWithPrefix(f *flag.FlagSet, prefix string) {
	f.BoolVar(&cfg.Enabled, prefix+"enabled", false, "True to enable querier and store-gateway to discover blocks in the storage via bucket index instead of bucket scanning.")
	f.DurationVar(&cfg.UpdateOnErrorInterval, prefix+"update-on-error-interval", time.Minute, "How frequently a bucket index, which previously failed to load, should be tried to load again. This option is used only by querier.")
	f.DurationVar(&cfg.IdleTimeout, prefix+"idle-timeout", time.Hour, "How long a unused bucket index should be cached. Once this timeout expires, the unused bucket index is removed from the in-memory cache. This option is used only by querier.")
	f.DurationVar(&cfg.MaxStalePeriod, prefix+"max-stale-period", time.Hour, "The maximum allowed age of a bucket index (last updated) before queries start failing because the bucket index is too old. The bucket index is periodically updated by the compactor, while this check is enforced in the querier (at query time).")
}

// BlockDiscoveryStrategy configures how to list block IDs from object storage.
type BlockDiscoveryStrategy string

const (
	ConcurrentDiscovery  BlockDiscoveryStrategy = "concurrent"
	RecursiveDiscovery   BlockDiscoveryStrategy = "recursive"
	BucketIndexDiscovery BlockDiscoveryStrategy = "bucket_index"
)

var supportedBlockDiscoveryStrategies = []string{
	string(ConcurrentDiscovery),
	string(RecursiveDiscovery),
	string(BucketIndexDiscovery),
}