block: precalculate hashes if enabled and use them during compaction

Added the possibility to ignore certain directories in
objstore.{Download,DownloadDir}. Do not download files which have the
same hash as in remote object storage. Wire up `--hash-func` so that
writers could specify what hash function to use when uploading. There is
no performance impact if no hash function has been explicitly specified.
Clean up the removal of files logic in Thanos Compact to ensure we do
not remove something that exists on disk already.

Tested manually + new tests cover all of this more or less.

Signed-off-by: Giedrius Statkevičius <giedriuswork@gmail.com>

CHANGELOG.md

@@ -14,6 +14,7 @@ We use _breaking :warning:_ to mark changes that are not backward compatible (re
 ### Added
 
 - [#3469](https://github.com/thanos-io/thanos/pull/3469) StoreAPI: Added `hints` field to `LabelNamesRequest` and `LabelValuesRequest`. Hints in an opaque data structure that can be used to carry additional information from the store and its content is implementation specific.
+- [#3031](https://github.com/thanos-io/thanos/pull/3031) Compact/Sidecar/other writers: added `--hash-func`. If some function has been specified, writers calculate hashes using that function of each file in a block before uploading them. If those hashes exist in the `meta.json` file then Compact does a smart thing and does not download the files if they already exist on disk. This also means that the data directory passed to Thanos Compact is only *cleared once at boot* or *if everything succeeds*. So, if you, for example, use persistent volumes on k8s and your Thanos Compact crashes or fails to make an iteration properly then the last downloaded files are not wiped from the disk. The directories that were created the last time are only wiped again after a successful iteration or if the previously picked up blocks have disappeared.
 
 ### Fixed
 

cmd/thanos/compact.go

@@ -98,7 +98,7 @@ func runCompact(
 	component component.Component,
 	conf compactConfig,
 	flagsMap map[string]string,
-) error {
+) (rerr error) {
 	deleteDelay := time.Duration(conf.deleteDelay)
 	halted := promauto.With(reg).NewGauge(prometheus.GaugeOpts{
 		Name: "thanos_compact_halted",
@@ -266,11 +266,16 @@ func runCompact(
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
+
+	defer func() {
+		if rerr != nil {
+			cancel()
+		}
+	}()
 	// Instantiate the compactor with different time slices. Timestamps in TSDB
 	// are in milliseconds.
 	comp, err := tsdb.NewLeveledCompactor(ctx, reg, logger, levels, downsample.NewPool())
 	if err != nil {
-		cancel()
 		return errors.Wrap(err, "create compactor")
 	}
 
@@ -279,11 +284,23 @@ func runCompact(
 		downsamplingDir = path.Join(conf.dataDir, "downsample")
 	)
 
+	// Clean-up and create a fresh state at the beginning.
 	if err := os.RemoveAll(downsamplingDir); err != nil {
-		cancel()
 		return errors.Wrap(err, "clean working downsample directory")
 	}
 
+	if err := os.RemoveAll(compactDir); err != nil {
+		return errors.Wrap(err, "clean working compact directory")
+	}
+
+	if err := os.Mkdir(compactDir, os.ModePerm); err != nil {
+		return errors.Wrap(err, "create working compact directory")
+	}
+
+	if err := os.Mkdir(downsamplingDir, os.ModePerm); err != nil {
+		return errors.Wrap(err, "create working downsample directory")
+	}
+
 	grouper := compact.NewDefaultGrouper(
 		logger,
 		bkt,
@@ -292,6 +309,7 @@ func runCompact(
 		reg,
 		blocksMarked.WithLabelValues(metadata.DeletionMarkFilename),
 		garbageCollectedBlocks,
+		metadata.HashFunc(conf.hashFunc),
 	)
 	blocksCleaner := compact.NewBlocksCleaner(logger, bkt, ignoreDeletionMarkFilter, deleteDelay, blocksCleaned, blockCleanupFailures)
 	compactor, err := compact.NewBucketCompactor(
@@ -310,7 +328,6 @@ func runCompact(
 		conf.compactionConcurrency,
 	)
 	if err != nil {
-		cancel()
 		return errors.Wrap(err, "create bucket compactor")
 	}
 
@@ -351,11 +368,9 @@ func runCompact(
 	// Do it once at the beginning to ensure that it runs at least once before
 	// the main loop.
 	if err := sy.SyncMetas(ctx); err != nil {
-		cancel()
 		return errors.Wrap(err, "syncing metas")
 	}
 	if err := cleanPartialMarked(); err != nil {
-		cancel()
 		return errors.Wrap(err, "cleaning partial and marked blocks")
 	}
 
@@ -378,15 +393,15 @@ func runCompact(
 				downsampleMetrics.downsamples.WithLabelValues(groupKey)
 				downsampleMetrics.downsampleFailures.WithLabelValues(groupKey)
 			}
-			if err := downsampleBucket(ctx, logger, downsampleMetrics, bkt, sy.Metas(), downsamplingDir); err != nil {
+			if err := downsampleBucket(ctx, logger, downsampleMetrics, bkt, sy.Metas(), downsamplingDir, metadata.HashFunc(conf.hashFunc)); err != nil {
 				return errors.Wrap(err, "first pass of downsampling failed")
 			}
 
 			level.Info(logger).Log("msg", "start second pass of downsampling")
 			if err := sy.SyncMetas(ctx); err != nil {
 				return errors.Wrap(err, "sync before second pass of downsampling")
 			}
-			if err := downsampleBucket(ctx, logger, downsampleMetrics, bkt, sy.Metas(), downsamplingDir); err != nil {
+			if err := downsampleBucket(ctx, logger, downsampleMetrics, bkt, sy.Metas(), downsamplingDir, metadata.HashFunc(conf.hashFunc)); err != nil {
 				return errors.Wrap(err, "second pass of downsampling failed")
 			}
 			level.Info(logger).Log("msg", "downsampling iterations done")
@@ -539,6 +554,7 @@ type compactConfig struct {
 	webConf                                        webConfig
 	label                                          string
 	maxBlockIndexSize                              units.Base2Bytes
+	hashFunc                                       string
 }
 
 func (cc *compactConfig) registerFlag(cmd extkingpin.FlagClause) {
@@ -608,6 +624,9 @@ func (cc *compactConfig) registerFlag(cmd extkingpin.FlagClause) {
 		"Default is due to https://github.com/thanos-io/thanos/issues/1424, but it's overall recommended to keeps block size to some reasonable size.").
 		Hidden().Default("64GB").BytesVar(&cc.maxBlockIndexSize)
 
+	cmd.Flag("hash-func", "Specify which hash function to use when calculating the hashes of produced files. If no function has been specified, it does not happen. This permits avoiding downloading some files twice albeit at some performance cost. Possible values are: \"\", \"SHA256\".").
+		Default("").EnumVar(&cc.hashFunc, "SHA256", "")
+
 	cc.selectorRelabelConf = *extkingpin.RegisterSelectorRelabelFlags(cmd)
 
 	cc.webConf.registerFlag(cmd)

cmd/thanos/config.go

@@ -126,6 +126,7 @@ type shipperConfig struct {
 	uploadCompacted       bool
 	ignoreBlockSize       bool
 	allowOutOfOrderUpload bool
+	hashFunc              string
 }
 
 func (sc *shipperConfig) registerFlag(cmd extkingpin.FlagClause) *shipperConfig {
@@ -140,6 +141,8 @@ func (sc *shipperConfig) registerFlag(cmd extkingpin.FlagClause) *shipperConfig
 			"This can trigger compaction without those blocks and as a result will create an overlap situation. Set it to true if you have vertical compaction enabled and wish to upload blocks as soon as possible without caring"+
 			"about order.").
 		Default("false").Hidden().BoolVar(&sc.allowOutOfOrderUpload)
+	cmd.Flag("hash-func", "Specify which hash function to use when calculating the hashes of produced files. If no function has been specified, it does not happen. This permits avoiding downloading some files twice albeit at some performance cost. Possible values are: \"\", \"SHA256\".").
+		Default("").EnumVar(&sc.hashFunc, "SHA256", "")
 	return sc
 }
 

cmd/thanos/downsample.go

@@ -61,6 +61,7 @@ func RunDownsample(
 	dataDir string,
 	objStoreConfig *extflag.PathOrContent,
 	comp component.Component,
+	hashFunc metadata.HashFunc,
 ) error {
 	confContentYaml, err := objStoreConfig.Content()
 	if err != nil {
@@ -112,7 +113,7 @@ func RunDownsample(
 				metrics.downsamples.WithLabelValues(groupKey)
 				metrics.downsampleFailures.WithLabelValues(groupKey)
 			}
-			if err := downsampleBucket(ctx, logger, metrics, bkt, metas, dataDir); err != nil {
+			if err := downsampleBucket(ctx, logger, metrics, bkt, metas, dataDir, hashFunc); err != nil {
 				return errors.Wrap(err, "downsampling failed")
 			}
 
@@ -121,7 +122,7 @@ func RunDownsample(
 			if err != nil {
 				return errors.Wrap(err, "sync before second pass of downsampling")
 			}
-			if err := downsampleBucket(ctx, logger, metrics, bkt, metas, dataDir); err != nil {
+			if err := downsampleBucket(ctx, logger, metrics, bkt, metas, dataDir, hashFunc); err != nil {
 				return errors.Wrap(err, "downsampling failed")
 			}
 
@@ -151,22 +152,37 @@ func RunDownsample(
 	return nil
 }
 
+// removeAllNonMetaDirs removes all subdirectories and all files under the given dir
+// that do not correspond to any metas. This is needed in the case when
+// the downsampling process resumes without restarting the whole process
+// but the blocks do not exist in the remote object storage anymore.
+func removeAllNonMetaDirs(metas map[ulid.ULID]*metadata.Meta, dir string) error {
+	ignoreDirs := []string{}
+	for ulid := range metas {
+		ignoreDirs = append(ignoreDirs, ulid.String())
+	}
+	return runutil.DeleteAllExceptDirs(dir, ignoreDirs)
+}
+
 func downsampleBucket(
 	ctx context.Context,
 	logger log.Logger,
 	metrics *DownsampleMetrics,
 	bkt objstore.Bucket,
 	metas map[ulid.ULID]*metadata.Meta,
 	dir string,
-) error {
-	if err := os.RemoveAll(dir); err != nil {
-		return errors.Wrap(err, "clean working directory")
-	}
+	hashFunc metadata.HashFunc,
+) (rerr error) {
 	if err := os.MkdirAll(dir, 0777); err != nil {
 		return errors.Wrap(err, "create dir")
 	}
 
 	defer func() {
+		// Leave the downsample directory for inspection if it is a halt error
+		// or if it is not then so that possibly we would not have to download everything again.
+		if rerr != nil {
+			return
+		}
 		if err := os.RemoveAll(dir); err != nil {
 			level.Error(logger).Log("msg", "failed to remove downsample cache directory", "path", dir, "err", err)
 		}
@@ -194,6 +210,10 @@ func downsampleBucket(
 		}
 	}
 
+	if err := removeAllNonMetaDirs(metas, dir); err != nil {
+		level.Warn(logger).Log("msg", "failed deleting potentially outdated directories/files, some disk space usage might have leaked. Continuing", "err", err, "dir", dir)
+	}
+
 	for _, m := range metas {
 		switch m.Thanos.Downsample.Resolution {
 		case downsample.ResLevel0:
@@ -213,7 +233,8 @@ func downsampleBucket(
 			if m.MaxTime-m.MinTime < downsample.DownsampleRange0 {
 				continue
 			}
-			if err := processDownsampling(ctx, logger, bkt, m, dir, downsample.ResLevel1); err != nil {
+
+			if err := processDownsampling(ctx, logger, bkt, m, dir, downsample.ResLevel1, hashFunc); err != nil {
 				metrics.downsampleFailures.WithLabelValues(compact.DefaultGroupKey(m.Thanos)).Inc()
 				return errors.Wrap(err, "downsampling to 5 min")
 			}
@@ -236,7 +257,7 @@ func downsampleBucket(
 			if m.MaxTime-m.MinTime < downsample.DownsampleRange1 {
 				continue
 			}
-			if err := processDownsampling(ctx, logger, bkt, m, dir, downsample.ResLevel2); err != nil {
+			if err := processDownsampling(ctx, logger, bkt, m, dir, downsample.ResLevel2, hashFunc); err != nil {
 				metrics.downsampleFailures.WithLabelValues(compact.DefaultGroupKey(m.Thanos)).Inc()
 				return errors.Wrap(err, "downsampling to 60 min")
 			}
@@ -246,7 +267,7 @@ func downsampleBucket(
 	return nil
 }
 
-func processDownsampling(ctx context.Context, logger log.Logger, bkt objstore.Bucket, m *metadata.Meta, dir string, resolution int64) error {
+func processDownsampling(ctx context.Context, logger log.Logger, bkt objstore.Bucket, m *metadata.Meta, dir string, resolution int64, hashFunc metadata.HashFunc) error {
 	begin := time.Now()
 	bdir := filepath.Join(dir, m.ULID.String())
 
@@ -290,7 +311,7 @@ func processDownsampling(ctx context.Context, logger log.Logger, bkt objstore.Bu
 
 	begin = time.Now()
 
-	err = block.Upload(ctx, logger, bkt, resdir)
+	err = block.Upload(ctx, logger, bkt, resdir, hashFunc)
 	if err != nil {
 		return errors.Wrapf(err, "upload downsampled block %s", id)
 	}

cmd/thanos/main_test.go

@@ -17,6 +17,7 @@ import (
 	promtest "github.com/prometheus/client_golang/prometheus/testutil"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/thanos-io/thanos/pkg/block"
+	"github.com/thanos-io/thanos/pkg/block/metadata"
 	"github.com/thanos-io/thanos/pkg/compact"
 	"github.com/thanos-io/thanos/pkg/compact/downsample"
 	"github.com/thanos-io/thanos/pkg/objstore"
@@ -42,9 +43,9 @@ func TestCleanupDownsampleCacheFolder(t *testing.T) {
 			[]labels.Labels{{{Name: "a", Value: "1"}}},
 			1, 0, downsample.DownsampleRange0+1, // Pass the minimum DownsampleRange0 check.
 			labels.Labels{{Name: "e1", Value: "1"}},
-			downsample.ResLevel0)
+			downsample.ResLevel0, false)
 		testutil.Ok(t, err)
-		testutil.Ok(t, block.Upload(ctx, logger, bkt, path.Join(dir, id.String())))
+		testutil.Ok(t, block.Upload(ctx, logger, bkt, path.Join(dir, id.String()), metadata.NoneFunc))
 	}
 
 	meta, err := block.DownloadMeta(ctx, logger, bkt, id)
@@ -57,7 +58,7 @@ func TestCleanupDownsampleCacheFolder(t *testing.T) {
 
 	metas, _, err := metaFetcher.Fetch(ctx)
 	testutil.Ok(t, err)
-	testutil.Ok(t, downsampleBucket(ctx, logger, metrics, bkt, metas, dir))
+	testutil.Ok(t, downsampleBucket(ctx, logger, metrics, bkt, metas, dir, metadata.NoneFunc))
 	testutil.Equals(t, 1.0, promtest.ToFloat64(metrics.downsamples.WithLabelValues(compact.DefaultGroupKey(meta.Thanos))))
 
 	_, err = os.Stat(dir)

cmd/thanos/receive.go

@@ -21,6 +21,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/prometheus/pkg/labels"
 	"github.com/prometheus/prometheus/tsdb"
+	"github.com/thanos-io/thanos/pkg/block/metadata"
 	"github.com/thanos-io/thanos/pkg/extkingpin"
 
 	"github.com/thanos-io/thanos/pkg/component"
@@ -88,6 +89,9 @@ func registerReceive(app *extkingpin.App) {
 	walCompression := cmd.Flag("tsdb.wal-compression", "Compress the tsdb WAL.").Default("true").Bool()
 	noLockFile := cmd.Flag("tsdb.no-lockfile", "Do not create lockfile in TSDB data directory. In any case, the lockfiles will be deleted on next startup.").Default("false").Bool()
 
+	hashFunc := cmd.Flag("hash-func", "Specify which hash function to use when calculating the hashes of produced files. If no function has been specified, it does not happen. This permits avoiding downloading some files twice albeit at some performance cost. Possible values are: \"\", \"SHA256\".").
+		Default("").Enum("SHA256", "")
+
 	ignoreBlockSize := cmd.Flag("shipper.ignore-unequal-block-size", "If true receive will not require min and max block size flags to be set to the same value. Only use this if you want to keep long retention and compaction enabled, as in the worst case it can result in ~2h data loss for your Thanos bucket storage.").Default("false").Hidden().Bool()
 	allowOutOfOrderUpload := cmd.Flag("shipper.allow-out-of-order-uploads",
 		"If true, shipper will skip failed block uploads in the given iteration and retry later. This means that some newer blocks might be uploaded sooner than older blocks."+
@@ -168,6 +172,7 @@ func registerReceive(app *extkingpin.App) {
 			time.Duration(*forwardTimeout),
 			*allowOutOfOrderUpload,
 			component.Receive,
+			metadata.HashFunc(*hashFunc),
 		)
 	})
 }
@@ -207,6 +212,7 @@ func runReceive(
 	forwardTimeout time.Duration,
 	allowOutOfOrderUpload bool,
 	comp component.SourceStoreAPI,
+	hashFunc metadata.HashFunc,
 ) error {
 	logger = log.With(logger, "component", "receive")
 	level.Warn(logger).Log("msg", "setting up receive")
@@ -258,6 +264,7 @@ func runReceive(
 		tenantLabelName,
 		bkt,
 		allowOutOfOrderUpload,
+		hashFunc,
 	)
 	writer := receive.NewWriter(log.With(logger, "component", "receive-writer"), dbs)
 	webHandler := receive.NewHandler(log.With(logger, "component", "receive-handler"), &receive.Options{

cmd/thanos/rule.go

@@ -128,6 +128,9 @@ func registerRule(app *extkingpin.App) {
 			"about order.").
 		Default("false").Hidden().Bool()
 
+	hashFunc := cmd.Flag("hash-func", "Specify which hash function to use when calculating the hashes of produced files. If no function has been specified, it does not happen. This permits avoiding downloading some files twice albeit at some performance cost. Possible values are: \"\", \"SHA256\".").
+		Default("").Enum("SHA256", "")
+
 	cmd.Setup(func(g *run.Group, logger log.Logger, reg *prometheus.Registry, tracer opentracing.Tracer, reload <-chan struct{}, _ bool) error {
 		lset, err := parseFlagLabels(*labelStrs)
 		if err != nil {
@@ -215,6 +218,7 @@ func registerRule(app *extkingpin.App) {
 			*allowOutOfOrderUpload,
 			*httpMethod,
 			getFlagsMap(cmd.Flags()),
+			metadata.HashFunc(*hashFunc),
 		)
 	})
 }
@@ -305,6 +309,7 @@ func runRule(
 	allowOutOfOrderUpload bool,
 	httpMethod string,
 	flagsMap map[string]string,
+	hashFunc metadata.HashFunc,
 ) error {
 	metrics := newRuleMetrics(reg)
 
@@ -646,7 +651,7 @@ func runRule(
 			}
 		}()
 
-		s := shipper.New(logger, reg, dataDir, bkt, func() labels.Labels { return lset }, metadata.RulerSource, false, allowOutOfOrderUpload)
+		s := shipper.New(logger, reg, dataDir, bkt, func() labels.Labels { return lset }, metadata.RulerSource, false, allowOutOfOrderUpload, hashFunc)
 
 		ctx, cancel := context.WithCancel(context.Background())
 

cmd/thanos/sidecar.go

@@ -268,7 +268,7 @@ func runSidecar(
 			}
 
 			s := shipper.New(logger, reg, conf.tsdb.path, bkt, m.Labels, metadata.SidecarSource,
-				conf.shipper.uploadCompacted, conf.shipper.allowOutOfOrderUpload)
+				conf.shipper.uploadCompacted, conf.shipper.allowOutOfOrderUpload, metadata.HashFunc(conf.shipper.hashFunc))
 
 			return runutil.Repeat(30*time.Second, ctx.Done(), func() error {
 				if uploaded, err := s.Sync(ctx); err != nil {

cmd/thanos/tools_bucket.go

@@ -475,9 +475,11 @@ func registerBucketDownsample(app extkingpin.AppClause, objStoreConfig *extflag.
 	httpAddr, httpGracePeriod := extkingpin.RegisterHTTPFlags(cmd)
 	dataDir := cmd.Flag("data-dir", "Data directory in which to cache blocks and process downsamplings.").
 		Default("./data").String()
+	hashFunc := cmd.Flag("hash-func", "Specify which hash function to use when calculating the hashes of produced files. If no function has been specified, it does not happen. This permits avoiding downloading some files twice albeit at some performance cost. Possible values are: \"\", \"SHA256\".").
+		Default("").Enum("SHA256", "")
 
 	cmd.Setup(func(g *run.Group, logger log.Logger, reg *prometheus.Registry, tracer opentracing.Tracer, _ <-chan struct{}, _ bool) error {
-		return RunDownsample(g, logger, reg, *httpAddr, time.Duration(*httpGracePeriod), *dataDir, objStoreConfig, component.Downsample)
+		return RunDownsample(g, logger, reg, *httpAddr, time.Duration(*httpGracePeriod), *dataDir, objStoreConfig, component.Downsample, metadata.HashFunc(*hashFunc))
 	})
 }
 

docs/components/compact.md

@@ -168,6 +168,12 @@ Flags:
                                 loaded, or compactor is ignoring the deletion
                                 because it's compacting the block at the same
                                 time.
+      --hash-func=              Specify which hash function to use when
+                                calculating the hashes of produced files. If no
+                                function has been specified, it does not happen.
+                                This permits avoiding downloading some files
+                                twice albeit at some performance cost. Possible
+                                values are: "", "SHA256".
       --selector.relabel-config-file=<file-path>
                                 Path to YAML file that contains relabeling
                                 configuration that allows selecting blocks. It