Write implements Wal.Write.
(l *kt.Log)
| 62 | |
| 63 | // Write implements Wal.Write. |
| 64 | func (p *LevelDBWal) Write(l *kt.Log) (err error) { |
| 65 | if atomic.LoadUint32(&p.closed) == 1 { |
| 66 | err = ErrWalClosed |
| 67 | return |
| 68 | } |
| 69 | |
| 70 | // mark wal as already read |
| 71 | atomic.CompareAndSwapUint32(&p.read, 0, 1) |
| 72 | |
| 73 | if l == nil { |
| 74 | err = ErrInvalidLog |
| 75 | return |
| 76 | } |
| 77 | |
| 78 | // build header headerKey |
| 79 | headerKey := append(append([]byte(nil), logHeaderKeyPrefix...), p.uint64ToBytes(l.Index)...) |
| 80 | |
| 81 | if _, err = p.db.Get(headerKey, nil); err != nil && err != leveldb.ErrNotFound { |
| 82 | err = errors.Wrap(err, "access leveldb failed") |
| 83 | return |
| 84 | } else if err == nil { |
| 85 | err = ErrAlreadyExists |
| 86 | return |
| 87 | } |
| 88 | |
| 89 | dataKey := append(append([]byte(nil), logDataKeyPrefix...), p.uint64ToBytes(l.Index)...) |
| 90 | |
| 91 | // write data first |
| 92 | var enc *bytes.Buffer |
| 93 | if enc, err = utils.EncodeMsgPack(l.Data); err != nil { |
| 94 | err = errors.Wrap(err, "encode log data failed") |
| 95 | return |
| 96 | } |
| 97 | |
| 98 | if err = p.db.Put(dataKey, enc.Bytes(), nil); err != nil { |
| 99 | err = errors.Wrap(err, "write log data failed") |
| 100 | return |
| 101 | } |
| 102 | |
| 103 | // write header |
| 104 | l.DataLength = uint64(enc.Len()) |
| 105 | |
| 106 | if enc, err = utils.EncodeMsgPack(l.LogHeader); err != nil { |
| 107 | err = errors.Wrap(err, "encode log header failed") |
| 108 | return |
| 109 | } |
| 110 | |
| 111 | // save header |
| 112 | if err = p.db.Put(headerKey, enc.Bytes(), nil); err != nil { |
| 113 | err = errors.Wrap(err, "encode log header failed") |
| 114 | return |
| 115 | } |
| 116 | |
| 117 | return |
| 118 | } |
| 119 | |
| 120 | // Read implements Wal.Read. |
| 121 | func (p *LevelDBWal) Read() (l *kt.Log, err error) { |