use context to cancel compactions

Signed-off-by: Krasi Georgiev <kgeorgie@redhat.com>

CHANGELOG.md

@@ -1,4 +1,6 @@
 ## master / unreleased
+ - [CHANGE]  `NewLeveledCompactor` takes a context so that a compaction is canceled when closing the db.
+
 
 ## 0.3.0
 

block_test.go

@@ -14,6 +14,7 @@
 package tsdb
 
 import (
+	"context"
 	"io/ioutil"
 	"math/rand"
 	"os"
@@ -105,7 +106,7 @@ func createPopulatedBlock(tb testing.TB, dir string, nSeries int, mint, maxt int
 		testutil.Ok(tb, err)
 	}
 
-	compactor, err := NewLeveledCompactor(nil, log.NewNopLogger(), []int64{1000000}, nil)
+	compactor, err := NewLeveledCompactor(context.Background(), nil, log.NewNopLogger(), []int64{1000000}, nil)
 	testutil.Ok(tb, err)
 
 	testutil.Ok(tb, os.MkdirAll(dir, 0777))

compact.go

@@ -14,6 +14,7 @@
 package tsdb
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"math/rand"
@@ -71,6 +72,7 @@ type LeveledCompactor struct {
 	logger    log.Logger
 	ranges    []int64
 	chunkPool chunkenc.Pool
+	ctx       context.Context
 }
 
 type compactorMetrics struct {
@@ -128,7 +130,7 @@ func newCompactorMetrics(r prometheus.Registerer) *compactorMetrics {
 }
 
 // NewLeveledCompactor returns a LeveledCompactor.
-func NewLeveledCompactor(r prometheus.Registerer, l log.Logger, ranges []int64, pool chunkenc.Pool) (*LeveledCompactor, error) {
+func NewLeveledCompactor(ctx context.Context, r prometheus.Registerer, l log.Logger, ranges []int64, pool chunkenc.Pool) (*LeveledCompactor, error) {
 	if len(ranges) == 0 {
 		return nil, errors.Errorf("at least one range must be provided")
 	}
@@ -140,6 +142,7 @@ func NewLeveledCompactor(r prometheus.Registerer, l log.Logger, ranges []int64,
 		chunkPool: pool,
 		logger:    l,
 		metrics:   newCompactorMetrics(r),
+		ctx:       ctx,
 	}, nil
 }
 
@@ -441,8 +444,11 @@ func (w *instrumentedChunkWriter) WriteChunks(chunks ...chunks.Meta) error {
 func (c *LeveledCompactor) write(dest string, meta *BlockMeta, blocks ...BlockReader) (err error) {
 	dir := filepath.Join(dest, meta.ULID.String())
 	tmp := dir + ".tmp"
-
+	var writers []io.Closer
 	defer func(t time.Time) {
+		for _, w := range writers {
+			w.Close()
+		}
 		if err != nil {
 			c.metrics.failed.Inc()
 			// TODO(gouthamve): Handle error how?
@@ -470,7 +476,7 @@ func (c *LeveledCompactor) write(dest string, meta *BlockMeta, blocks ...BlockRe
 	if err != nil {
 		return errors.Wrap(err, "open chunk writer")
 	}
-	defer chunkw.Close()
+	writers = append(writers, chunkw)
 	// Record written chunk sizes on level 1 compactions.
 	if meta.Compaction.Level == 1 {
 		chunkw = &instrumentedChunkWriter{
@@ -485,12 +491,25 @@ func (c *LeveledCompactor) write(dest string, meta *BlockMeta, blocks ...BlockRe
 	if err != nil {
 		return errors.Wrap(err, "open index writer")
 	}
-	defer indexw.Close()
+	writers = append(writers, indexw)
 
 	if err := c.populateBlock(blocks, meta, indexw, chunkw); err != nil {
 		return errors.Wrap(err, "write compaction")
 	}
 
+	// Remove tmp folder and return early when the compaction was canceled.
+	select {
+	case <-c.ctx.Done():
+		for _, w := range writers {
+			w.Close()
+		}
+		if err := os.RemoveAll(tmp); err != nil {
+			level.Error(c.logger).Log("msg", "removed tmp folder after canceled compaction", "err", err.Error())
+		}
+		return
+	default:
+	}
+
 	if err = writeMetaFile(tmp, meta); err != nil {
 		return errors.Wrap(err, "write merged meta")
 	}
@@ -499,11 +518,10 @@ func (c *LeveledCompactor) write(dest string, meta *BlockMeta, blocks ...BlockRe
 	// though these are covered under defer. This is because in Windows,
 	// you cannot delete these unless they are closed and the defer is to
 	// make sure they are closed if the function exits due to an error above.
-	if err = chunkw.Close(); err != nil {
-		return errors.Wrap(err, "close chunk writer")
-	}
-	if err = indexw.Close(); err != nil {
-		return errors.Wrap(err, "close index writer")
+	for _, w := range writers {
+		if err := w.Close(); err != nil {
+			return err
+		}
 	}
 
 	// Create an empty tombstones file.
@@ -554,6 +572,12 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 	defer func() { closeAll(closers...) }()
 
 	for i, b := range blocks {
+		select {
+		case <-c.ctx.Done():
+			return nil
+		default:
+		}
+
 		indexr, err := b.Index()
 		if err != nil {
 			return errors.Wrapf(err, "open index reader for block %s", b)
@@ -610,6 +634,11 @@ func (c *LeveledCompactor) populateBlock(blocks []BlockReader, meta *BlockMeta,
 	}
 
 	for set.Next() {
+		select {
+		case <-c.ctx.Done():
+			return nil
+		default:
+		}
 		lset, chks, dranges := set.At() // The chunks here are not fully deleted.
 
 		// Skip the series with all deleted chunks.

compact_test.go

@@ -14,6 +14,7 @@
 package tsdb
 
 import (
+	"context"
 	"io/ioutil"
 	"math"
 	"os"
@@ -151,7 +152,7 @@ func TestNoPanicFor0Tombstones(t *testing.T) {
 		},
 	}
 
-	c, err := NewLeveledCompactor(nil, nil, []int64{50}, nil)
+	c, err := NewLeveledCompactor(context.Background(), nil, nil, []int64{50}, nil)
 	testutil.Ok(t, err)
 
 	c.plan(metas)
@@ -159,7 +160,7 @@ func TestNoPanicFor0Tombstones(t *testing.T) {
 
 func TestLeveledCompactor_plan(t *testing.T) {
 	// This mimicks our default ExponentialBlockRanges with min block size equals to 20.
-	compactor, err := NewLeveledCompactor(nil, nil, []int64{
+	compactor, err := NewLeveledCompactor(context.Background(), nil, nil, []int64{
 		20,
 		60,
 		180,
@@ -322,7 +323,7 @@ func TestLeveledCompactor_plan(t *testing.T) {
 }
 
 func TestRangeWithFailedCompactionWontGetSelected(t *testing.T) {
-	compactor, err := NewLeveledCompactor(nil, nil, []int64{
+	compactor, err := NewLeveledCompactor(context.Background(), nil, nil, []int64{
 		20,
 		60,
 		240,
@@ -372,7 +373,7 @@ func TestRangeWithFailedCompactionWontGetSelected(t *testing.T) {
 }
 
 func TestCompactionFailWillCleanUpTempDir(t *testing.T) {
-	compactor, err := NewLeveledCompactor(nil, log.NewNopLogger(), []int64{
+	compactor, err := NewLeveledCompactor(context.Background(), nil, log.NewNopLogger(), []int64{
 		20,
 		60,
 		240,
@@ -647,7 +648,7 @@ func TestCompaction_populateBlock(t *testing.T) {
 				blocks = append(blocks, &mockBReader{ir: ir, cr: cr})
 			}
 
-			c, err := NewLeveledCompactor(nil, nil, []int64{0}, nil)
+			c, err := NewLeveledCompactor(context.Background(), nil, nil, []int64{0}, nil)
 			testutil.Ok(t, err)
 
 			meta := &BlockMeta{

db.go

@@ -16,6 +16,7 @@ package tsdb
 
 import (
 	"bytes"
+	"context"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -119,6 +120,9 @@ type DB struct {
 	// changing the autoCompact var.
 	autoCompactMtx sync.Mutex
 	autoCompact    bool
+
+	// Cancel a running compaction when a shutdown is initiated.
+	compactCnl func()
 }
 
 type dbMetrics struct {
@@ -258,10 +262,12 @@ func Open(dir string, l log.Logger, r prometheus.Registerer, opts *Options) (db
 		db.lockf = lockf
 	}
 
-	db.compactor, err = NewLeveledCompactor(r, l, opts.BlockRanges, db.chunkPool)
+	ctx, cnl := context.WithCancel(context.Background())
+	db.compactor, err = NewLeveledCompactor(ctx, r, l, opts.BlockRanges, db.chunkPool)
 	if err != nil {
 		return nil, errors.Wrap(err, "create leveled compactor")
 	}
+	db.compactCnl = cnl
 
 	wlog, err := wal.New(l, r, filepath.Join(dir, "wal"))
 	if err != nil {
@@ -726,6 +732,7 @@ func (db *DB) Head() *Head {
 // Close the partition.
 func (db *DB) Close() error {
 	close(db.stopc)
+	db.compactCnl()
 	<-db.donec
 
 	db.mtx.Lock()