frostfs-node/pkg/util/state/storage.go

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package state
import (
"encoding/binary"
"encoding/hex"
"fmt"
"go.etcd.io/bbolt"
)
// PersistentStorage is a wrapper around persistent K:V db that
// provides thread safe functions to set and fetch state variables
// of the Inner Ring and Storage applications.
type PersistentStorage struct {
db *bbolt.DB
}
var stateBucket = []byte("state")
// NewPersistentStorage creates a new instance of a storage with 0600 rights.
func NewPersistentStorage(path string) (*PersistentStorage, error) {
db, err := bbolt.Open(path, 0o600, nil)
if err != nil {
return nil, fmt.Errorf("can't open bbolt at %s: %w", path, err)
}
return &PersistentStorage{db: db}, nil
}
// SetUInt32 sets a uint32 value in the storage.
func (p PersistentStorage) SetUInt32(key []byte, value uint32) error {
return p.db.Update(func(tx *bbolt.Tx) error {
b, err := tx.CreateBucketIfNotExists(stateBucket)
if err != nil {
return fmt.Errorf("can't create state bucket in state persistent storage: %w", err)
}
buf := make([]byte, 8)
binary.LittleEndian.PutUint64(buf, uint64(value))
return b.Put(key, buf)
})
}
// UInt32 returns a uint32 value from persistent storage. If the value does not exist,
// returns 0.
func (p PersistentStorage) UInt32(key []byte) (n uint32, err error) {
err = p.db.View(func(tx *bbolt.Tx) error {
b := tx.Bucket(stateBucket)
if b == nil {
return nil // if bucket not exists yet, return default n = 0
}
buf := b.Get(key)
if len(buf) != 8 {
return fmt.Errorf("persistent storage does not store uint data in %s", hex.EncodeToString(key))
}
u64 := binary.LittleEndian.Uint64(buf)
n = uint32(u64)
return nil
})
return
}
// Close closes persistent database instance.
func (p PersistentStorage) Close() error {
return p.db.Close()
}