// Copyright 2016 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"
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"
)
var (
plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "compactor")
)
const (
checkCompactionInterval = 5 * time.Minute
executeCompactionInterval = time.Hour
)
type Compactable interface {
Compact(ctx context.Context, r *pb.CompactionRequest) (*pb.CompactionResponse, error)
}
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
}
return t.revs[i], t.revs[i+1:]
}