Compactor: Add Revisional compactor

compactor/compactor.go

@@ -15,14 +15,13 @@
 package compactor
 
 import (
-	"sync"
+	"fmt"
 	"time"
 
-	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
-	"github.com/coreos/etcd/mvcc"
 	"github.com/coreos/pkg/capnslog"
-	"github.com/jonboulle/clockwork"
 	"golang.org/x/net/context"
+
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 )
 
 var (
@@ -32,8 +31,24 @@ var (
 const (
 	checkCompactionInterval   = 5 * time.Minute
 	executeCompactionInterval = time.Hour
+
+	ModePeriodic = "periodic"
+	ModeRevision = "revision"
 )
 
+// Compactor purges old log from the storage periodically.
+type Compactor interface {
+	// Run starts the main loop of the compactor in background.
+	// Use Stop() to halt the loop and release the resource.
+	Run()
+	// Stop halts the main loop of the compactor.
+	Stop()
+	// Pause temporally suspend the compactor not to run compaction. Resume() to unpose.
+	Pause()
+	// Resume restarts the compactor suspended by Pause().
+	Resume()
+}
+
 type Compactable interface {
 	Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error)
 }
@@ -42,96 +57,13 @@ type RevGetter interface {
 	Rev() int64
 }
 
-// Periodic compacts the log by purging revisions older than
-// the configured retention time. Compaction happens hourly.
-type Periodic struct {
-	clock        clockwork.Clock
-	periodInHour int
-
-	rg RevGetter
-	c  Compactable
-
-	revs   []int64
-	ctx    context.Context
-	cancel context.CancelFunc
-
-	mu     sync.Mutex
-	paused bool
-}
-
-func NewPeriodic(h int, rg RevGetter, c Compactable) *Periodic {
-	return &Periodic{
-		clock:        clockwork.NewRealClock(),
-		periodInHour: h,
-		rg:           rg,
-		c:            c,
-	}
-}
-
-func (t *Periodic) Run() {
-	t.ctx, t.cancel = context.WithCancel(context.Background())
-	t.revs = make([]int64, 0)
-	clock := t.clock
-
-	go func() {
-		last := clock.Now()
-		for {
-			t.revs = append(t.revs, t.rg.Rev())
-			select {
-			case <-t.ctx.Done():
-				return
-			case <-clock.After(checkCompactionInterval):
-				t.mu.Lock()
-				p := t.paused
-				t.mu.Unlock()
-				if p {
-					continue
-				}
-			}
-
-			if clock.Now().Sub(last) < executeCompactionInterval {
-				continue
-			}
-
-			rev, remaining := t.getRev(t.periodInHour)
-			if rev < 0 {
-				continue
-			}
-
-			plog.Noticef("Starting auto-compaction at revision %d", rev)
-			_, err := t.c.Compact(t.ctx, &pb.CompactionRequest{Revision: rev})
-			if err == nil || err == mvcc.ErrCompacted {
-				t.revs = remaining
-				last = clock.Now()
-				plog.Noticef("Finished auto-compaction at revision %d", rev)
-			} else {
-				plog.Noticef("Failed auto-compaction at revision %d (%v)", err, rev)
-				plog.Noticef("Retry after %v", checkCompactionInterval)
-			}
-		}
-	}()
-}
-
-func (t *Periodic) Stop() {
-	t.cancel()
-}
-
-func (t *Periodic) Pause() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-	t.paused = true
-}
-
-func (t *Periodic) Resume() {
-	t.mu.Lock()
-	defer t.mu.Unlock()
-	t.paused = false
-}
-
-func (t *Periodic) getRev(h int) (int64, []int64) {
-	i := len(t.revs) - int(time.Duration(h)*time.Hour/checkCompactionInterval)
-	if i < 0 {
-		return -1, t.revs
+func New(mode string, retention int, rg RevGetter, c Compactable) (Compactor, error) {
+	switch mode {
+	case ModePeriodic:
+		return NewPeriodic(retention, rg, c), nil
+	case ModeRevision:
+		return NewRevision(int64(retention), rg, c), nil
+	default:
+		return nil, fmt.Errorf("unsupported compaction mode %s", mode)
 	}
-	return t.revs[i], t.revs[i+1:]
 }

compactor/compactor_test.go

@@ -15,108 +15,11 @@
 package compactor
 
 import (
-	"reflect"
-	"testing"
-	"time"
-
 	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
 	"github.com/coreos/etcd/pkg/testutil"
-	"github.com/jonboulle/clockwork"
 	"golang.org/x/net/context"
 )
 
-func TestPeriodic(t *testing.T) {
-	retentionHours := 2
-
-	fc := clockwork.NewFakeClock()
-	rg := &fakeRevGetter{testutil.NewRecorderStream(), 0}
-	compactable := &fakeCompactable{testutil.NewRecorderStream()}
-	tb := &Periodic{
-		clock:        fc,
-		periodInHour: retentionHours,
-		rg:           rg,
-		c:            compactable,
-	}
-
-	tb.Run()
-	defer tb.Stop()
-
-	n := int(time.Hour / checkCompactionInterval)
-	// collect 5 hours of revisions
-	for i := 0; i < 5; i++ {
-		// advance one hour, one revision for each interval
-		for j := 0; j < n; j++ {
-			rg.Wait(1)
-			fc.Advance(checkCompactionInterval)
-		}
-
-		// compaction doesn't happen til 2 hours elapses
-		if i+1 < retentionHours {
-			continue
-		}
-
-		a, err := compactable.Wait(1)
-		if err != nil {
-			t.Fatal(err)
-		}
-		expectedRevision := int64(1 + (i+1)*n - retentionHours*n)
-		if !reflect.DeepEqual(a[0].Params[0], &pb.CompactionRequest{Revision: expectedRevision}) {
-			t.Errorf("compact request = %v, want %v", a[0].Params[0], &pb.CompactionRequest{Revision: expectedRevision})
-		}
-	}
-
-	// unblock the rev getter, so we can stop the compactor routine.
-	_, err := rg.Wait(1)
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
-func TestPeriodicPause(t *testing.T) {
-	fc := clockwork.NewFakeClock()
-	compactable := &fakeCompactable{testutil.NewRecorderStream()}
-	rg := &fakeRevGetter{testutil.NewRecorderStream(), 0}
-	tb := &Periodic{
-		clock:        fc,
-		periodInHour: 1,
-		rg:           rg,
-		c:            compactable,
-	}
-
-	tb.Run()
-	tb.Pause()
-
-	// tb will collect 3 hours of revisions but not compact since paused
-	n := int(time.Hour / checkCompactionInterval)
-	for i := 0; i < 3*n; i++ {
-		rg.Wait(1)
-		fc.Advance(checkCompactionInterval)
-	}
-	// tb ends up waiting for the clock
-
-	select {
-	case a := <-compactable.Chan():
-		t.Fatalf("unexpected action %v", a)
-	case <-time.After(10 * time.Millisecond):
-	}
-
-	// tb resumes to being blocked on the clock
-	tb.Resume()
-
-	// unblock clock, will kick off a compaction at hour 3:05
-	rg.Wait(1)
-	fc.Advance(checkCompactionInterval)
-	a, err := compactable.Wait(1)
-	if err != nil {
-		t.Fatal(err)
-	}
-	// compact the revision from hour 2:05
-	wreq := &pb.CompactionRequest{Revision: int64(1 + 2*n + 1)}
-	if !reflect.DeepEqual(a[0].Params[0], wreq) {
-		t.Errorf("compact request = %v, want %v", a[0].Params[0], wreq.Revision)
-	}
-}
-
 type fakeCompactable struct {
 	testutil.Recorder
 }

compactor/periodic.go

@@ -0,0 +1,122 @@
+// Copyright 2017 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package compactor
+
+import (
+	"sync"
+	"time"
+
+	"github.com/jonboulle/clockwork"
+	"golang.org/x/net/context"
+
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+	"github.com/coreos/etcd/mvcc"
+)
+
+// Periodic compacts the log by purging revisions older than
+// the configured retention time. Compaction happens hourly.
+type Periodic struct {
+	clock        clockwork.Clock
+	periodInHour int
+
+	rg RevGetter
+	c  Compactable
+
+	revs   []int64
+	ctx    context.Context
+	cancel context.CancelFunc
+
+	mu     sync.Mutex
+	paused bool
+}
+
+// NewPeriodic creates a new instance of Periodic compactor that purges
+// the log older than h hours.
+func NewPeriodic(h int, rg RevGetter, c Compactable) *Periodic {
+	return &Periodic{
+		clock:        clockwork.NewRealClock(),
+		periodInHour: h,
+		rg:           rg,
+		c:            c,
+	}
+}
+
+func (t *Periodic) Run() {
+	t.ctx, t.cancel = context.WithCancel(context.Background())
+	t.revs = make([]int64, 0)
+	clock := t.clock
+
+	go func() {
+		last := clock.Now()
+		for {
+			t.revs = append(t.revs, t.rg.Rev())
+			select {
+			case <-t.ctx.Done():
+				return
+			case <-clock.After(checkCompactionInterval):
+				t.mu.Lock()
+				p := t.paused
+				t.mu.Unlock()
+				if p {
+					continue
+				}
+			}
+
+			if clock.Now().Sub(last) < executeCompactionInterval {
+				continue
+			}
+
+			rev, remaining := t.getRev(t.periodInHour)
+			if rev < 0 {
+				continue
+			}
+
+			plog.Noticef("Starting auto-compaction at revision %d (retention: %d hours)", rev, t.periodInHour)
+			_, err := t.c.Compact(t.ctx, &pb.CompactionRequest{Revision: rev})
+			if err == nil || err == mvcc.ErrCompacted {
+				t.revs = remaining
+				last = clock.Now()
+				plog.Noticef("Finished auto-compaction at revision %d", rev)
+			} else {
+				plog.Noticef("Failed auto-compaction at revision %d (%v)", err, rev)
+				plog.Noticef("Retry after %v", checkCompactionInterval)
+			}
+		}
+	}()
+}
+
+func (t *Periodic) Stop() {
+	t.cancel()
+}
+
+func (t *Periodic) Pause() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.paused = true
+}
+
+func (t *Periodic) Resume() {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	t.paused = false
+}
+
+func (t *Periodic) getRev(h int) (int64, []int64) {
+	i := len(t.revs) - int(time.Duration(h)*time.Hour/checkCompactionInterval)
+	if i < 0 {
+		return -1, t.revs
+	}
+	return t.revs[i], t.revs[i+1:]
+}