mirror of
https://github.com/prometheus/prometheus.git
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211 lines
4.9 KiB
Go
211 lines
4.9 KiB
Go
// Copyright 2014 The Prometheus Authors
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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 index
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import (
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"encoding"
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"github.com/syndtr/goleveldb/leveldb"
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leveldb_filter "github.com/syndtr/goleveldb/leveldb/filter"
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leveldb_iterator "github.com/syndtr/goleveldb/leveldb/iterator"
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leveldb_opt "github.com/syndtr/goleveldb/leveldb/opt"
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leveldb_util "github.com/syndtr/goleveldb/leveldb/util"
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)
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var (
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keyspace = &leveldb_util.Range{
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Start: nil,
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Limit: nil,
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}
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iteratorOpts = &leveldb_opt.ReadOptions{
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DontFillCache: true,
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}
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)
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// LevelDB is a LevelDB-backed sorted KeyValueStore.
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type LevelDB struct {
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storage *leveldb.DB
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readOpts *leveldb_opt.ReadOptions
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writeOpts *leveldb_opt.WriteOptions
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}
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// LevelDBOptions provides options for a LevelDB.
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type LevelDBOptions struct {
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Path string // Base path to store files.
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CacheSizeBytes int
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}
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// NewLevelDB returns a newly allocated LevelDB-backed KeyValueStore ready to
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// use.
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func NewLevelDB(o LevelDBOptions) (KeyValueStore, error) {
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options := &leveldb_opt.Options{
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BlockCacheCapacity: o.CacheSizeBytes,
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Filter: leveldb_filter.NewBloomFilter(10),
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}
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storage, err := leveldb.OpenFile(o.Path, options)
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if err != nil {
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return nil, err
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}
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return &LevelDB{
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storage: storage,
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readOpts: &leveldb_opt.ReadOptions{},
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writeOpts: &leveldb_opt.WriteOptions{},
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}, nil
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}
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// NewBatch implements KeyValueStore.
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func (l *LevelDB) NewBatch() Batch {
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return &LevelDBBatch{
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batch: &leveldb.Batch{},
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}
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}
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// Close implements KeyValueStore.
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func (l *LevelDB) Close() error {
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return l.storage.Close()
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}
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// Get implements KeyValueStore.
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func (l *LevelDB) Get(key encoding.BinaryMarshaler, value encoding.BinaryUnmarshaler) (bool, error) {
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k, err := key.MarshalBinary()
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if err != nil {
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return false, err
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}
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raw, err := l.storage.Get(k, l.readOpts)
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if err == leveldb.ErrNotFound {
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return false, nil
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}
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if err != nil {
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return false, err
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}
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if value == nil {
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return true, nil
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}
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return true, value.UnmarshalBinary(raw)
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}
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// Has implements KeyValueStore.
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func (l *LevelDB) Has(key encoding.BinaryMarshaler) (has bool, err error) {
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return l.Get(key, nil)
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}
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// Delete implements KeyValueStore.
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func (l *LevelDB) Delete(key encoding.BinaryMarshaler) (bool, error) {
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k, err := key.MarshalBinary()
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if err != nil {
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return false, err
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}
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// Note that Delete returns nil if k does not exist. So we have to test
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// for existence with Has first.
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if has, err := l.storage.Has(k, l.readOpts); !has || err != nil {
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return false, err
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}
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if err = l.storage.Delete(k, l.writeOpts); err != nil {
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return false, err
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}
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return true, nil
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}
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// Put implements KeyValueStore.
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func (l *LevelDB) Put(key, value encoding.BinaryMarshaler) error {
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k, err := key.MarshalBinary()
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if err != nil {
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return err
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}
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v, err := value.MarshalBinary()
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if err != nil {
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return err
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}
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return l.storage.Put(k, v, l.writeOpts)
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}
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// Commit implements KeyValueStore.
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func (l *LevelDB) Commit(b Batch) error {
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return l.storage.Write(b.(*LevelDBBatch).batch, l.writeOpts)
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}
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// ForEach implements KeyValueStore.
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func (l *LevelDB) ForEach(cb func(kv KeyValueAccessor) error) error {
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snap, err := l.storage.GetSnapshot()
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if err != nil {
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return err
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}
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defer snap.Release()
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iter := snap.NewIterator(keyspace, iteratorOpts)
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kv := &levelDBKeyValueAccessor{it: iter}
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for valid := iter.First(); valid; valid = iter.Next() {
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if err = iter.Error(); err != nil {
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return err
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}
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if err := cb(kv); err != nil {
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return err
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}
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}
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return nil
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}
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// LevelDBBatch is a Batch implementation for LevelDB.
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type LevelDBBatch struct {
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batch *leveldb.Batch
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}
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// Put implements Batch.
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func (b *LevelDBBatch) Put(key, value encoding.BinaryMarshaler) error {
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k, err := key.MarshalBinary()
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if err != nil {
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return err
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}
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v, err := value.MarshalBinary()
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if err != nil {
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return err
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}
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b.batch.Put(k, v)
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return nil
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}
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// Delete implements Batch.
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func (b *LevelDBBatch) Delete(key encoding.BinaryMarshaler) error {
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k, err := key.MarshalBinary()
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if err != nil {
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return err
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}
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b.batch.Delete(k)
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return nil
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}
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// Reset implements Batch.
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func (b *LevelDBBatch) Reset() {
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b.batch.Reset()
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}
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// levelDBKeyValueAccessor implements KeyValueAccessor.
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type levelDBKeyValueAccessor struct {
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it leveldb_iterator.Iterator
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}
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func (i *levelDBKeyValueAccessor) Key(key encoding.BinaryUnmarshaler) error {
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return key.UnmarshalBinary(i.it.Key())
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}
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func (i *levelDBKeyValueAccessor) Value(value encoding.BinaryUnmarshaler) error {
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return value.UnmarshalBinary(i.it.Value())
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}
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