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74 lines
2.1 KiB
74 lines
2.1 KiB
package db
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import (
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"fmt"
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"strings"
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)
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type DBBackendType string
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// These are valid backend types.
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const (
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// LevelDBBackend is a legacy type. Defaults to goleveldb unless cleveldb
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// build tag was used, in which it becomes cleveldb.
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// Deprecated: Use concrete types (golevedb, cleveldb, etc.)
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LevelDBBackend DBBackendType = "leveldb"
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// GoLevelDBBackend represents goleveldb (github.com/syndtr/goleveldb - most
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// popular implementation)
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// - pure go
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// - stable
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GoLevelDBBackend DBBackendType = "goleveldb"
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// CLevelDBBackend represents cleveldb (uses levigo wrapper)
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// - fast
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// - requires gcc
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// - use cleveldb build tag (go build -tags cleveldb)
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CLevelDBBackend DBBackendType = "cleveldb"
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// MemDBBackend represents in-memoty key value store, which is mostly used
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// for testing.
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MemDBBackend DBBackendType = "memdb"
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// FSDBBackend represents filesystem database
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// - EXPERIMENTAL
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// - slow
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FSDBBackend DBBackendType = "fsdb"
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// BoltDBBackend represents bolt (uses etcd's fork of bolt -
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// github.com/etcd-io/bbolt)
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// - EXPERIMENTAL
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// - may be faster is some use-cases (random reads - indexer)
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// - use boltdb build tag (go build -tags boltdb)
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BoltDBBackend DBBackendType = "boltdb"
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)
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type dbCreator func(name string, dir string) (DB, error)
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var backends = map[DBBackendType]dbCreator{}
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func registerDBCreator(backend DBBackendType, creator dbCreator, force bool) {
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_, ok := backends[backend]
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if !force && ok {
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return
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}
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backends[backend] = creator
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}
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// NewDB creates a new database of type backend with the given name.
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// NOTE: function panics if:
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// - backend is unknown (not registered)
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// - creator function, provided during registration, returns error
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func NewDB(name string, backend DBBackendType, dir string) DB {
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dbCreator, ok := backends[backend]
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if !ok {
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keys := make([]string, len(backends))
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i := 0
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for k := range backends {
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keys[i] = string(k)
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i++
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}
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panic(fmt.Sprintf("Unknown db_backend %s, expected either %s", backend, strings.Join(keys, " or ")))
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}
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db, err := dbCreator(name, dir)
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if err != nil {
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panic(fmt.Sprintf("Error initializing DB: %v", err))
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}
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return db
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}
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