Anton Kaliaev a7358bc69f
libs/db: conditional compilation (#3628)
* libs/db: conditional compilation

For cleveldb: go build -tags cleveldb
For boltdb: go build -tags boltdb

Fixes #3611

* document db_backend param better

* remove deprecated LevelDBBackend

* update changelog

* add missing lines

* add new line

* fix TestRemoteDB

* add a line about boltdb tag

* Revert "remove deprecated LevelDBBackend"

This reverts commit 1aa85453f76605e0c4d967601bbe26240e668d51.

* make PR non breaking

* change DEPRECATED label format

https://stackoverflow.com/a/36360323/820520
2019-05-07 12:33:47 +04:00

75 lines
2.1 KiB
Go

package db
import (
"fmt"
"strings"
)
type DBBackendType string
// These are valid backend types.
const (
// LevelDBBackend is a legacy type. Defaults to goleveldb unless cleveldb
// build tag was used, in which it becomes cleveldb.
// Deprecated: Use concrete types (golevedb, cleveldb, etc.)
LevelDBBackend DBBackendType = "leveldb"
// GoLevelDBBackend represents goleveldb (github.com/syndtr/goleveldb - most
// popular implementation)
// - pure go
// - stable
GoLevelDBBackend DBBackendType = "goleveldb"
// CLevelDBBackend represents cleveldb (uses levigo wrapper)
// - fast
// - requires gcc
// - use cleveldb build tag (go build -tags cleveldb)
CLevelDBBackend DBBackendType = "cleveldb"
// MemDBBackend represents in-memoty key value store, which is mostly used
// for testing.
MemDBBackend DBBackendType = "memdb"
// FSDBBackend represents filesystem database
// - EXPERIMENTAL
// - slow
FSDBBackend DBBackendType = "fsdb"
// BoltDBBackend represents bolt (uses etcd's fork of bolt -
// github.com/etcd-io/bbolt)
// - EXPERIMENTAL
// - may be faster is some use-cases (random reads - indexer)
// - use boltdb build tag (go build -tags boltdb)
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
}