This is an implementation of the LevelDB key/value database in the Go programming language.
Installation
go get github.com/syndtr/goleveldb/leveldb
Requirements
- Need at least
go1.5or newer.
Usage
Create or open a database:
// The returned DB instance is safe for concurrent use. Which mean that all
// DB's methods may be called concurrently from multiple goroutine.
db, err := leveldb.OpenFile("path/to/db", nil)
...
defer db.Close()
...
Read or modify the database content:
// Remember that the contents of the returned slice should not be modified.
data, err := db.Get([]byte("key"), nil)
...
err = db.Put([]byte("key"), []byte("value"), nil)
...
err = db.Delete([]byte("key"), nil)
...
Iterate over database content:
iter := db.NewIterator(nil, nil)
for iter.Next() {
// Remember that the contents of the returned slice should not be modified, and
// only valid until the next call to Next.
key := iter.Key()
value := iter.Value()
...
}
iter.Release()
err = iter.Error()
...
Seek-then-Iterate:
iter := db.NewIterator(nil, nil)
for ok := iter.Seek(key); ok; ok = iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
Iterate over subset of database content:
iter := db.NewIterator(&util.Range{Start: []byte("foo"), Limit: []byte("xoo")}, nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
Iterate over subset of database content with a particular prefix:
iter := db.NewIterator(util.BytesPrefix([]byte("foo-")), nil)
for iter.Next() {
// Use key/value.
...
}
iter.Release()
err = iter.Error()
...
Batch writes:
batch := new(leveldb.Batch)
batch.Put([]byte("foo"), []byte("value"))
batch.Put([]byte("bar"), []byte("another value"))
batch.Delete([]byte("baz"))
err = db.Write(batch, nil)
...
Use bloom filter:
o := &opt.Options{
Filter: filter.NewBloomFilter(10),
}
db, err := leveldb.OpenFile("path/to/db", o)
...
defer db.Close()
...
Documentation
You can read package documentation here.