frostfs-node/pkg/local_object_storage/metabase/shard_id.go

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package meta
import (
"github.com/nspcc-dev/neo-go/pkg/util/slice"
"go.etcd.io/bbolt"
)
var (
shardInfoBucket = []byte{shardInfoPrefix}
shardIDKey = []byte("id")
)
// ReadShardID reads shard id from db.
// If id is missing, returns nil, nil.
func (db *DB) ReadShardID() ([]byte, error) {
db.modeMtx.RLock()
defer db.modeMtx.RUnlock()
if db.mode.NoMetabase() {
return nil, ErrDegradedMode
}
var id []byte
err := db.boltDB.View(func(tx *bbolt.Tx) error {
b := tx.Bucket(shardInfoBucket)
if b != nil {
id = slice.Copy(b.Get(shardIDKey))
}
return nil
})
return id, err
}
// WriteShardID writes shard it to db.
func (db *DB) WriteShardID(id []byte) error {
db.modeMtx.RLock()
defer db.modeMtx.RUnlock()
if db.mode.NoMetabase() {
return ErrDegradedMode
}
return db.boltDB.Update(func(tx *bbolt.Tx) error {
b, err := tx.CreateBucketIfNotExists(shardInfoBucket)
if err != nil {
return err
}
return b.Put(shardIDKey, id)
})
}