159 lines
3.3 KiB
Go
159 lines
3.3 KiB
Go
// Copyright 2015 CoreOS, Inc.
|
|
//
|
|
// 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 backend
|
|
|
|
import (
|
|
"fmt"
|
|
"hash/crc32"
|
|
"io"
|
|
"log"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"github.com/coreos/etcd/Godeps/_workspace/src/github.com/boltdb/bolt"
|
|
)
|
|
|
|
type Backend interface {
|
|
BatchTx() BatchTx
|
|
Snapshot() Snapshot
|
|
Hash() (uint32, error)
|
|
// Size returns the current size of the backend.
|
|
Size() int64
|
|
ForceCommit()
|
|
Close() error
|
|
}
|
|
|
|
type Snapshot interface {
|
|
// Size gets the size of the snapshot.
|
|
Size() int64
|
|
// WriteTo writes the snapshot into the given writter.
|
|
WriteTo(w io.Writer) (n int64, err error)
|
|
// Close closes the snapshot.
|
|
Close() error
|
|
}
|
|
|
|
type backend struct {
|
|
db *bolt.DB
|
|
|
|
batchInterval time.Duration
|
|
batchLimit int
|
|
batchTx *batchTx
|
|
size int64
|
|
|
|
stopc chan struct{}
|
|
donec chan struct{}
|
|
}
|
|
|
|
func New(path string, d time.Duration, limit int) Backend {
|
|
return newBackend(path, d, limit)
|
|
}
|
|
|
|
func newBackend(path string, d time.Duration, limit int) *backend {
|
|
db, err := bolt.Open(path, 0600, boltOpenOptions)
|
|
if err != nil {
|
|
log.Panicf("backend: cannot open database at %s (%v)", path, err)
|
|
}
|
|
|
|
b := &backend{
|
|
db: db,
|
|
|
|
batchInterval: d,
|
|
batchLimit: limit,
|
|
|
|
stopc: make(chan struct{}),
|
|
donec: make(chan struct{}),
|
|
}
|
|
b.batchTx = newBatchTx(b)
|
|
go b.run()
|
|
return b
|
|
}
|
|
|
|
// BatchTx returns the current batch tx in coalescer. The tx can be used for read and
|
|
// write operations. The write result can be retrieved within the same tx immediately.
|
|
// The write result is isolated with other txs until the current one get committed.
|
|
func (b *backend) BatchTx() BatchTx {
|
|
return b.batchTx
|
|
}
|
|
|
|
// force commit the current batching tx.
|
|
func (b *backend) ForceCommit() {
|
|
b.batchTx.Commit()
|
|
}
|
|
|
|
func (b *backend) Snapshot() Snapshot {
|
|
tx, err := b.db.Begin(false)
|
|
if err != nil {
|
|
log.Fatalf("storage: cannot begin tx (%s)", err)
|
|
}
|
|
return &snapshot{tx}
|
|
}
|
|
|
|
func (b *backend) Hash() (uint32, error) {
|
|
h := crc32.New(crc32.MakeTable(crc32.Castagnoli))
|
|
|
|
err := b.db.View(func(tx *bolt.Tx) error {
|
|
c := tx.Cursor()
|
|
for next, _ := c.First(); next != nil; next, _ = c.Next() {
|
|
b := tx.Bucket(next)
|
|
if b == nil {
|
|
return fmt.Errorf("cannot get hash of bucket %s", string(next))
|
|
}
|
|
h.Write(next)
|
|
b.ForEach(func(k, v []byte) error {
|
|
h.Write(k)
|
|
h.Write(v)
|
|
return nil
|
|
})
|
|
}
|
|
return nil
|
|
})
|
|
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
|
|
return h.Sum32(), nil
|
|
}
|
|
|
|
func (b *backend) Size() int64 {
|
|
return atomic.LoadInt64(&b.size)
|
|
}
|
|
|
|
func (b *backend) run() {
|
|
defer close(b.donec)
|
|
|
|
for {
|
|
select {
|
|
case <-time.After(b.batchInterval):
|
|
case <-b.stopc:
|
|
b.batchTx.CommitAndStop()
|
|
return
|
|
}
|
|
b.batchTx.Commit()
|
|
}
|
|
}
|
|
|
|
func (b *backend) Close() error {
|
|
close(b.stopc)
|
|
<-b.donec
|
|
return b.db.Close()
|
|
}
|
|
|
|
type snapshot struct {
|
|
*bolt.Tx
|
|
}
|
|
|
|
func (s *snapshot) Close() error { return s.Tx.Rollback() }
|