nimbusdb

nimbusdb

WARNING: nimbusdb is in early stages of development; do not use this in production.

Persistent key-value store based on Bitcask paper.

nimbusdb is a fast, lightweight, and scalable key-value store based on Bitcask.

nimbusdb maintains an active datafile to which data is written. When it crosses a threshold, the datafile is made inactive, and a new datafile is created. As time passes, expired or deleted keys take up space that is not useful. Hence, a process called merge is done to remove all expired or deleted keys and free up space.

Features

Usage

Initialize db connection

d, err := nimbusdb.Open(&nimbusdb.Options{Path: "/path/to/data/directory"})
if err != nil {
  // handle error
}
defer d.Close()

Set

kvPair := &nimbusdb.KeyValuePair{
  Key:   []byte("key"),
  Value: []byte("value"),
  Ttl: 5 * time.Minute, // Optional, default is 1 week
}
setValue, err := d.Set(kvPair)
if err != nil {
  // handle error
}

Get

value, err := d.Get([]byte("key"))
if err != nil {
  // handle error
}

Delete

value, err := d.Delete([]byte("key"))
if err != nil {
  // handle error
}

Sync

This does the merge process. This can be an expensive operation, hence it is better to run this periodically and whenever the traffic is low.

err := d.Sync()
if err != nil {
  // handle error
}

Batch Operations

d, err := nimbusdb.Open(&nimbusdb.Options{Path: "/path/to/data/directory"})
if err != nil {
  // handle error
}
defer d.Close()
b, err := d.NewBatch()
if err != nil {
  // handle error
}
defer b.Close()

_, err = b.Set([]byte("key"), []byte("value")) // not written to disk yet.
if err != nil {
  // handle error
}

key, err := b.Get([]byte("key"))
if err != nil {
  // handle error
}

err = b.Delete([]byte("key"))
if err != nil {
  // handle error
}

exists, err := b.Exists([]byte("key"))
if err != nil {
  // handle error
}

b.Commit() // write all pending writes to disk
b.Rollback() // discard all pending writes

Watch keys

func watchKeyChange(ch chan nimbusdb.WatcherEvent) {
  for event := range ch {
    switch event.EventType {
      case "CREATE":
        // Handle create key event
        break

      case "UPDATE":
        // Handle update key event
        break

      case "DELETE":
        // Handle delete key event
        break
    }
  }
}

func main() {
  d, err := nimbusdb.Open(&nimbusdb.Options{Path: "/path/to/data/directory", ShouldWatch: true})
  if err != nil {
    // handle error
  }
  defer d.Close()
  defer d.CloseWatch() // optional
  
  watchChannel, err := d.Watch()
  if err != nil {
    // handle error
  }
  
  go watchEvents(watchChannel)

  kvPair := &nimbusdb.KeyValuePair{
    Key:   []byte("key"),
    Value: []byte("value"),
  }
  setValue, err := d.Set(kvPair) // will trigger an CREATE event
  if err != nil {
    // handle error
  }

  setValue, err := d.Set(kvPair) // will trigger an UPDATE event
  if err != nil {
    // handle error
  }

  err = d.Delete(kvPair.Key) // will trigger an DELETE event
  if err != nil {
    // handle error
  }
}

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