Anton Kaliaev debf8f70c9
libs/db: bbolt (etcd's fork of bolt) (#3610)
Description:

    add boltdb implement for db interface.

    The boltdb is safe and high performence embedded KV database. It is based on B+tree and Mmap.
    Now it is maintained by etcd-io org. https://github.com/etcd-io/bbolt
    It is much better than LSM tree (levelDB) when RANDOM and SCAN read.

Replaced #3604
Refs #1835

Commits:

* add boltdb for storage

* update boltdb in gopkg.toml

* update bbolt in Gopkg.lock

* dep update  Gopkg.lock

* add boltdb'bucket when create Boltdb

* some modifies

* address my own comments

* fix most of the Iterator tests for boltdb

* bolt does not support concurrent writes while iterating

* add WARNING word

* note that ReadOnly option is not supported

* fixes after Ismail's review

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* panic if View returns error

plus specify bucket in the top comment
2019-05-06 13:42:21 +04:00

56 lines
1.4 KiB
Go

package db
import (
"fmt"
"strings"
)
//----------------------------------------
// Main entry
type DBBackendType string
const (
LevelDBBackend DBBackendType = "leveldb" // legacy, defaults to goleveldb unless +gcc
CLevelDBBackend DBBackendType = "cleveldb"
GoLevelDBBackend DBBackendType = "goleveldb"
MemDBBackend DBBackendType = "memdb"
FSDBBackend DBBackendType = "fsdb" // using the filesystem naively
BoltDBBackend DBBackendType = "boltdb"
)
type dbCreator func(name string, dir string) (DB, error)
var backends = map[DBBackendType]dbCreator{}
func registerDBCreator(backend DBBackendType, creator dbCreator, force bool) {
_, ok := backends[backend]
if !force && ok {
return
}
backends[backend] = creator
}
// NewDB creates a new database of type backend with the given name.
// NOTE: function panics if:
// - backend is unknown (not registered)
// - creator function, provided during registration, returns error
func NewDB(name string, backend DBBackendType, dir string) DB {
dbCreator, ok := backends[backend]
if !ok {
keys := make([]string, len(backends))
i := 0
for k := range backends {
keys[i] = string(k)
i++
}
panic(fmt.Sprintf("Unknown db_backend %s, expected either %s", backend, strings.Join(keys, " or ")))
}
db, err := dbCreator(name, dir)
if err != nil {
panic(fmt.Sprintf("Error initializing DB: %v", err))
}
return db
}