/
fetcher.go
605 lines (518 loc) · 18.7 KB
/
fetcher.go
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// SPDX-License-Identifier: AGPL-3.0-only
// Provenance-includes-location: https://github.com/thanos-io/thanos/blob/main/pkg/block/fetcher.go
// Provenance-includes-license: Apache-2.0
// Provenance-includes-copyright: The Thanos Authors.
package block
import (
"context"
"encoding/json"
"io"
"os"
"path"
"path/filepath"
"sync"
"time"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/golang/groupcache/singleflight"
"github.com/grafana/dskit/multierror"
"github.com/grafana/dskit/runutil"
"github.com/oklog/ulid"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/client_golang/prometheus/promauto"
"github.com/thanos-io/objstore"
"golang.org/x/sync/errgroup"
"github.com/grafana/mimir/pkg/util/extprom"
)
// FetcherMetrics holds metrics tracked by the metadata fetcher. This struct and its fields are exported
// to allow depending projects (eg. Cortex) to implement their own custom metadata fetcher while tracking
// compatible metrics.
type FetcherMetrics struct {
Syncs prometheus.Counter
SyncFailures prometheus.Counter
SyncDuration prometheus.Histogram
Synced *extprom.TxGaugeVec
}
// Submit applies new values for metrics tracked by transaction GaugeVec.
func (s *FetcherMetrics) Submit() {
s.Synced.Submit()
}
// ResetTx starts new transaction for metrics tracked by transaction GaugeVec.
func (s *FetcherMetrics) ResetTx() {
s.Synced.ResetTx()
}
const (
fetcherSubSys = "blocks_meta"
CorruptedMeta = "corrupted-meta-json"
NoMeta = "no-meta-json"
LoadedMeta = "loaded"
FailedMeta = "failed"
// Synced label values.
labelExcludedMeta = "label-excluded"
timeExcludedMeta = "time-excluded"
duplicateMeta = "duplicate"
// Blocks that are marked for deletion can be loaded as well. This is done to make sure that we load blocks that are meant to be deleted,
// but don't have a replacement block yet.
MarkedForDeletionMeta = "marked-for-deletion"
// MarkedForNoCompactionMeta is label for blocks which are loaded but also marked for no compaction. This label is also counted in `loaded` label metric.
MarkedForNoCompactionMeta = "marked-for-no-compact"
)
func NewFetcherMetrics(reg prometheus.Registerer, syncedExtraLabels [][]string) *FetcherMetrics {
var m FetcherMetrics
m.Syncs = promauto.With(reg).NewCounter(prometheus.CounterOpts{
Subsystem: fetcherSubSys,
Name: "syncs_total",
Help: "Total blocks metadata synchronization attempts",
})
m.SyncFailures = promauto.With(reg).NewCounter(prometheus.CounterOpts{
Subsystem: fetcherSubSys,
Name: "sync_failures_total",
Help: "Total blocks metadata synchronization failures",
})
m.SyncDuration = promauto.With(reg).NewHistogram(prometheus.HistogramOpts{
Subsystem: fetcherSubSys,
Name: "sync_duration_seconds",
Help: "Duration of the blocks metadata synchronization in seconds",
Buckets: []float64{0.01, 1, 10, 100, 300, 600, 1000},
})
m.Synced = extprom.NewTxGaugeVec(
reg,
prometheus.GaugeOpts{
Subsystem: fetcherSubSys,
Name: "synced",
Help: "Number of block metadata synced",
},
[]string{"state"},
append([][]string{
{CorruptedMeta},
{NoMeta},
{LoadedMeta},
{FailedMeta},
{labelExcludedMeta},
{timeExcludedMeta},
{duplicateMeta},
{MarkedForDeletionMeta},
{MarkedForNoCompactionMeta},
}, syncedExtraLabels...)...,
)
return &m
}
type MetadataFetcher interface {
Fetch(ctx context.Context) (metas map[ulid.ULID]*Meta, partial map[ulid.ULID]error, err error)
}
// GaugeVec hides something like a Prometheus GaugeVec or an extprom.TxGaugeVec.
type GaugeVec interface {
WithLabelValues(lvs ...string) prometheus.Gauge
}
// MetadataFilter allows filtering or modifying metas from the provided map or returns error.
type MetadataFilter interface {
Filter(ctx context.Context, metas map[ulid.ULID]*Meta, synced GaugeVec) error
}
// MetaFetcher is a struct that synchronizes filtered metadata of all block in the object storage with the local state.
// Go-routine safe.
type MetaFetcher struct {
logger log.Logger
concurrency int
bkt objstore.InstrumentedBucketReader
metrics *FetcherMetrics
filters []MetadataFilter
// Optional local directory to cache meta.json files.
cacheDir string
g singleflight.Group
mtx sync.Mutex
cached map[ulid.ULID]*Meta
}
// NewMetaFetcher returns a MetaFetcher.
func NewMetaFetcher(logger log.Logger, concurrency int, bkt objstore.InstrumentedBucketReader, dir string, reg prometheus.Registerer, filters []MetadataFilter) (*MetaFetcher, error) {
if logger == nil {
logger = log.NewNopLogger()
}
cacheDir := ""
if dir != "" {
cacheDir = filepath.Join(dir, "meta-syncer")
if err := os.MkdirAll(cacheDir, os.ModePerm); err != nil {
return nil, err
}
}
return &MetaFetcher{
logger: log.With(logger, "component", "block.MetaFetcher"),
concurrency: concurrency,
bkt: bkt,
cacheDir: cacheDir,
cached: map[ulid.ULID]*Meta{},
metrics: NewFetcherMetrics(reg, nil),
filters: filters,
}, nil
}
var (
ErrorSyncMetaNotFound = errors.New("meta.json not found")
ErrorSyncMetaCorrupted = errors.New("meta.json corrupted")
)
// loadMeta returns metadata from object storage or error.
// It returns ErrorSyncMetaNotFound and ErrorSyncMetaCorrupted sentinel errors in those cases.
func (f *MetaFetcher) loadMeta(ctx context.Context, id ulid.ULID) (*Meta, error) {
var (
metaFile = path.Join(id.String(), MetaFilename)
cachedBlockDir = filepath.Join(f.cacheDir, id.String())
)
// Block meta.json file is immutable, so we lookup the cache as first thing without issuing
// any API call to the object storage. This significantly reduce the pressure on the object
// storage.
//
// Details of all possible cases:
//
// - The block upload is in progress: the meta.json file is guaranteed to be uploaded at last.
// When we'll try to read it from object storage (later on), it will fail with ErrorSyncMetaNotFound
// which is correctly handled by the caller (partial block).
//
// - The block upload is completed: this is the normal case. meta.json file still exists in the
// object storage and it's expected to match the locally cached one (because it's immutable by design).
//
// - The block has been marked for deletion: the deletion hasn't started yet, so the full block (including
// the meta.json file) is still in the object storage. This case is not different than the previous one.
//
// - The block deletion is in progress: loadMeta() function may return the cached meta.json while it should
// return ErrorSyncMetaNotFound. This is a race condition that could happen even if we check the meta.json
// file in the storage, because the deletion could start right after we check it but before the MetaFetcher
// completes its sync.
//
// - The block has been deleted: the loadMeta() function will not be called at all, because the block
// was not discovered while iterating the bucket since all its files were already deleted.
if m, seen := f.cached[id]; seen {
return m, nil
}
// Best effort load from local dir.
if f.cacheDir != "" {
m, err := ReadMetaFromDir(cachedBlockDir)
if err == nil {
return m, nil
}
if !errors.Is(err, os.ErrNotExist) {
level.Warn(f.logger).Log("msg", "best effort read of the local meta.json failed; removing cached block dir", "dir", cachedBlockDir, "err", err)
if err := os.RemoveAll(cachedBlockDir); err != nil {
level.Warn(f.logger).Log("msg", "best effort remove of cached dir failed; ignoring", "dir", cachedBlockDir, "err", err)
}
}
}
r, err := f.bkt.ReaderWithExpectedErrs(f.bkt.IsObjNotFoundErr).Get(ctx, metaFile)
if f.bkt.IsObjNotFoundErr(err) {
// Meta.json was deleted between bkt.Exists and here.
return nil, errors.Wrapf(ErrorSyncMetaNotFound, "%v", err)
}
if err != nil {
return nil, errors.Wrapf(err, "get meta file: %v", metaFile)
}
defer runutil.CloseWithLogOnErr(f.logger, r, "close bkt meta get")
metaContent, err := io.ReadAll(r)
if err != nil {
return nil, errors.Wrapf(err, "read meta file: %v", metaFile)
}
m := &Meta{}
if err := json.Unmarshal(metaContent, m); err != nil {
return nil, errors.Wrapf(ErrorSyncMetaCorrupted, "meta.json %v unmarshal: %v", metaFile, err)
}
if m.Version != TSDBVersion1 {
return nil, errors.Errorf("unexpected meta file: %s version: %d", metaFile, m.Version)
}
// Best effort cache in local dir.
if f.cacheDir != "" {
if err := os.MkdirAll(cachedBlockDir, os.ModePerm); err != nil {
level.Warn(f.logger).Log("msg", "best effort mkdir of the meta.json block dir failed; ignoring", "dir", cachedBlockDir, "err", err)
}
if err := m.WriteToDir(f.logger, cachedBlockDir); err != nil {
level.Warn(f.logger).Log("msg", "best effort save of the meta.json to local dir failed; ignoring", "dir", cachedBlockDir, "err", err)
}
}
return m, nil
}
type response struct {
metas map[ulid.ULID]*Meta
partial map[ulid.ULID]error
// If metaErr > 0 it means incomplete view, so some metas, failed to be loaded.
metaErrs multierror.MultiError
// Track the number of blocks not returned because of various reasons.
noMetasCount float64
corruptedMetasCount float64
markedForDeletionCount float64
}
func (f *MetaFetcher) fetchMetadata(ctx context.Context, excludeMarkedForDeletion bool) (interface{}, error) {
var (
resp = response{
metas: make(map[ulid.ULID]*Meta),
partial: make(map[ulid.ULID]error),
}
eg errgroup.Group
ch = make(chan ulid.ULID, f.concurrency)
mtx sync.Mutex
)
level.Debug(f.logger).Log("msg", "fetching meta data", "concurrency", f.concurrency)
// Get the list of blocks marked for deletion so that we'll exclude them (if required).
var markedForDeletion map[ulid.ULID]struct{}
if excludeMarkedForDeletion {
var err error
markedForDeletion, err = ListBlockDeletionMarks(ctx, f.bkt)
if err != nil {
return nil, err
}
}
// Run workers.
for i := 0; i < f.concurrency; i++ {
eg.Go(func() error {
for id := range ch {
meta, err := f.loadMeta(ctx, id)
if err == nil {
mtx.Lock()
resp.metas[id] = meta
mtx.Unlock()
continue
}
if errors.Is(err, ErrorSyncMetaNotFound) {
mtx.Lock()
resp.noMetasCount++
mtx.Unlock()
} else if errors.Is(err, ErrorSyncMetaCorrupted) {
mtx.Lock()
resp.corruptedMetasCount++
mtx.Unlock()
} else {
mtx.Lock()
resp.metaErrs.Add(err)
mtx.Unlock()
continue
}
mtx.Lock()
resp.partial[id] = err
mtx.Unlock()
}
return nil
})
}
// Workers scheduled, distribute blocks.
eg.Go(func() error {
defer close(ch)
return f.bkt.Iter(ctx, "", func(name string) error {
id, ok := IsBlockDir(name)
if !ok {
return nil
}
// If requested, skip any block marked for deletion.
if _, marked := markedForDeletion[id]; excludeMarkedForDeletion && marked {
resp.markedForDeletionCount++
return nil
}
select {
case <-ctx.Done():
return ctx.Err()
case ch <- id:
}
return nil
})
})
if err := eg.Wait(); err != nil {
return nil, errors.Wrap(err, "MetaFetcher: iter bucket")
}
if len(resp.metaErrs) > 0 {
return resp, nil
}
// Only for complete view of blocks update the cache.
cached := make(map[ulid.ULID]*Meta, len(resp.metas))
for id, m := range resp.metas {
cached[id] = m
}
f.mtx.Lock()
f.cached = cached
f.mtx.Unlock()
// Best effort cleanup of disk-cached metas.
if f.cacheDir != "" {
fis, err := os.ReadDir(f.cacheDir)
names := make([]string, 0, len(fis))
for _, fi := range fis {
names = append(names, fi.Name())
}
if err != nil {
level.Warn(f.logger).Log("msg", "best effort remove of not needed cached dirs failed; ignoring", "err", err)
} else {
for _, n := range names {
id, ok := IsBlockDir(n)
if !ok {
continue
}
if _, ok := resp.metas[id]; ok {
continue
}
cachedBlockDir := filepath.Join(f.cacheDir, id.String())
// No such block loaded, remove the local dir.
if err := os.RemoveAll(cachedBlockDir); err != nil {
level.Warn(f.logger).Log("msg", "best effort remove of not needed cached dir failed; ignoring", "dir", cachedBlockDir, "err", err)
}
}
}
}
return resp, nil
}
// Fetch returns all block metas as well as partial blocks (blocks without or with corrupted meta file) from the bucket.
// It's caller responsibility to not change the returned metadata files. Maps can be modified.
//
// Returned error indicates a failure in fetching metadata. Returned meta can be assumed as correct, with some blocks missing.
func (f *MetaFetcher) Fetch(ctx context.Context) (metas map[ulid.ULID]*Meta, partials map[ulid.ULID]error, err error) {
metas, partials, err = f.fetch(ctx, false)
return
}
// FetchWithoutMarkedForDeletion returns all block metas as well as partial blocks (blocks without or with corrupted meta file) from the bucket.
// This function excludes all blocks marked for deletion (no deletion delay applied).
// It's caller responsibility to not change the returned metadata files. Maps can be modified.
//
// Returned error indicates a failure in fetching metadata. Returned meta can be assumed as correct, with some blocks missing.
func (f *MetaFetcher) FetchWithoutMarkedForDeletion(ctx context.Context) (metas map[ulid.ULID]*Meta, partials map[ulid.ULID]error, err error) {
metas, partials, err = f.fetch(ctx, true)
return
}
func (f *MetaFetcher) fetch(ctx context.Context, excludeMarkedForDeletion bool) (_ map[ulid.ULID]*Meta, _ map[ulid.ULID]error, err error) {
start := time.Now()
defer func() {
f.metrics.SyncDuration.Observe(time.Since(start).Seconds())
if err != nil {
f.metrics.SyncFailures.Inc()
}
}()
f.metrics.Syncs.Inc()
f.metrics.ResetTx()
// Run this in thread safe run group.
v, err := f.g.Do("", func() (i interface{}, err error) {
// NOTE: First go routine context will go through.
return f.fetchMetadata(ctx, excludeMarkedForDeletion)
})
if err != nil {
return nil, nil, err
}
resp := v.(response)
// Copy as same response might be reused by different goroutines.
metas := make(map[ulid.ULID]*Meta, len(resp.metas))
for id, m := range resp.metas {
metas[id] = m
}
f.metrics.Synced.WithLabelValues(FailedMeta).Set(float64(len(resp.metaErrs)))
f.metrics.Synced.WithLabelValues(NoMeta).Set(resp.noMetasCount)
f.metrics.Synced.WithLabelValues(CorruptedMeta).Set(resp.corruptedMetasCount)
if excludeMarkedForDeletion {
f.metrics.Synced.WithLabelValues(MarkedForDeletionMeta).Set(resp.markedForDeletionCount)
}
for _, filter := range f.filters {
// NOTE: filter can update synced metric accordingly to the reason of the exclude.
if err := filter.Filter(ctx, metas, f.metrics.Synced); err != nil {
return nil, nil, errors.Wrap(err, "filter metas")
}
}
f.metrics.Synced.WithLabelValues(LoadedMeta).Set(float64(len(metas)))
f.metrics.Submit()
if len(resp.metaErrs) > 0 {
return metas, resp.partial, errors.Wrap(resp.metaErrs.Err(), "incomplete view")
}
level.Info(f.logger).Log("msg", "successfully synchronized block metadata", "duration", time.Since(start).String(), "duration_ms", time.Since(start).Milliseconds(), "cached", f.countCached(), "returned", len(metas), "partial", len(resp.partial))
return metas, resp.partial, nil
}
func (f *MetaFetcher) countCached() int {
f.mtx.Lock()
defer f.mtx.Unlock()
return len(f.cached)
}
// BlockIDLabel is a special label that will have an ULID of the meta.json being referenced to.
const BlockIDLabel = "__block_id"
// IgnoreDeletionMarkFilter is a filter that filters out the blocks that are marked for deletion after a given delay.
// The delay duration is to make sure that the replacement block can be fetched before we filter out the old block.
// Delay is not considered when computing DeletionMarkBlocks map.
// Not go-routine safe.
type IgnoreDeletionMarkFilter struct {
logger log.Logger
delay time.Duration
concurrency int
bkt objstore.InstrumentedBucketReader
mtx sync.Mutex
deletionMarkMap map[ulid.ULID]*DeletionMark
}
// NewIgnoreDeletionMarkFilter creates IgnoreDeletionMarkFilter.
func NewIgnoreDeletionMarkFilter(logger log.Logger, bkt objstore.InstrumentedBucketReader, delay time.Duration, concurrency int) *IgnoreDeletionMarkFilter {
return &IgnoreDeletionMarkFilter{
logger: logger,
bkt: bkt,
delay: delay,
concurrency: concurrency,
}
}
// DeletionMarkBlocks returns block ids that were marked for deletion.
func (f *IgnoreDeletionMarkFilter) DeletionMarkBlocks() map[ulid.ULID]*DeletionMark {
f.mtx.Lock()
defer f.mtx.Unlock()
deletionMarkMap := make(map[ulid.ULID]*DeletionMark, len(f.deletionMarkMap))
for id, meta := range f.deletionMarkMap {
deletionMarkMap[id] = meta
}
return deletionMarkMap
}
// Filter filters out blocks that are marked for deletion after a given delay.
// It also returns the blocks that can be deleted since they were uploaded delay duration before current time.
func (f *IgnoreDeletionMarkFilter) Filter(ctx context.Context, metas map[ulid.ULID]*Meta, synced GaugeVec) error {
deletionMarkMap := make(map[ulid.ULID]*DeletionMark)
// Make a copy of block IDs to check, in order to avoid concurrency issues
// between the scheduler and workers.
blockIDs := make([]ulid.ULID, 0, len(metas))
for id := range metas {
blockIDs = append(blockIDs, id)
}
var (
eg errgroup.Group
ch = make(chan ulid.ULID, f.concurrency)
mtx sync.Mutex
)
for i := 0; i < f.concurrency; i++ {
eg.Go(func() error {
var lastErr error
for id := range ch {
m := &DeletionMark{}
if err := ReadMarker(ctx, f.logger, f.bkt, id.String(), m); err != nil {
if errors.Is(err, ErrorMarkerNotFound) {
continue
}
if errors.Is(err, ErrorUnmarshalMarker) {
level.Warn(f.logger).Log("msg", "found partial deletion-mark.json; if we will see it happening often for the same block, consider manually deleting deletion-mark.json from the object storage", "block", id, "err", err)
continue
}
// Remember the last error and continue to drain the channel.
lastErr = err
continue
}
// Keep track of the blocks marked for deletion and filter them out if their
// deletion time is greater than the configured delay.
mtx.Lock()
deletionMarkMap[id] = m
if time.Since(time.Unix(m.DeletionTime, 0)).Seconds() > f.delay.Seconds() {
synced.WithLabelValues(MarkedForDeletionMeta).Inc()
delete(metas, id)
}
mtx.Unlock()
}
return lastErr
})
}
// Workers scheduled, distribute blocks.
eg.Go(func() error {
defer close(ch)
for _, id := range blockIDs {
select {
case ch <- id:
// Nothing to do.
case <-ctx.Done():
return ctx.Err()
}
}
return nil
})
if err := eg.Wait(); err != nil {
return errors.Wrap(err, "filter blocks marked for deletion")
}
f.mtx.Lock()
f.deletionMarkMap = deletionMarkMap
f.mtx.Unlock()
return nil
}