mirror of
https://github.com/etcd-io/etcd.git
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106 lines
2.3 KiB
Go
106 lines
2.3 KiB
Go
// Copyright 2015 CoreOS, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package backend
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import (
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"io"
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"log"
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"time"
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"github.com/coreos/etcd/Godeps/_workspace/src/github.com/boltdb/bolt"
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)
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type Backend interface {
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BatchTx() BatchTx
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Snapshot(w io.Writer) (n int64, err error)
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ForceCommit()
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Close() error
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}
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type backend struct {
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db *bolt.DB
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batchInterval time.Duration
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batchLimit int
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batchTx *batchTx
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stopc chan struct{}
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donec chan struct{}
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}
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func New(path string, d time.Duration, limit int) Backend {
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return newBackend(path, d, limit)
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}
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func newBackend(path string, d time.Duration, limit int) *backend {
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db, err := bolt.Open(path, 0600, nil)
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if err != nil {
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log.Panicf("backend: cannot open database at %s (%v)", path, err)
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}
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b := &backend{
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db: db,
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batchInterval: d,
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batchLimit: limit,
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stopc: make(chan struct{}),
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donec: make(chan struct{}),
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}
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b.batchTx = newBatchTx(b)
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go b.run()
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return b
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}
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// BatchTx returns the current batch tx in coalescer. The tx can be used for read and
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// write operations. The write result can be retrieved within the same tx immediately.
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// The write result is isolated with other txs until the current one get committed.
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func (b *backend) BatchTx() BatchTx {
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return b.batchTx
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}
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// force commit the current batching tx.
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func (b *backend) ForceCommit() {
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b.batchTx.Commit()
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}
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func (b *backend) Snapshot(w io.Writer) (n int64, err error) {
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b.db.View(func(tx *bolt.Tx) error {
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n, err = tx.WriteTo(w)
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return nil
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})
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return n, err
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}
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func (b *backend) run() {
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defer close(b.donec)
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for {
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select {
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case <-time.After(b.batchInterval):
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case <-b.stopc:
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b.batchTx.CommitAndStop()
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return
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}
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b.batchTx.Commit()
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}
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}
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func (b *backend) Close() error {
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close(b.stopc)
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<-b.donec
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return b.db.Close()
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}
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