[#798] util/state: Implement persistent storage for application state

Signed-off-by: Alex Vanin <alexey@nspcc.ru>
This commit is contained in:
Alex Vanin 2021-09-06 15:43:30 +03:00 committed by Alex Vanin
parent b4378f7c11
commit 7f074a775e
2 changed files with 97 additions and 0 deletions

71
pkg/util/state/storage.go Normal file
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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 new instance of a storage with 0600 rights.
func NewPersistentStorage(path string) (*PersistentStorage, error) {
db, err := bbolt.Open(path, 0600, nil)
if err != nil {
return nil, fmt.Errorf("can't open bbolt at %s: %w", path, err)
}
return &PersistentStorage{db: db}, nil
}
// SetUInt32 sets 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 uint32 value from persistent storage. If value is not exists,
// 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()
}

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package state_test
import (
"path"
"testing"
"github.com/nspcc-dev/neofs-node/pkg/util/state"
"github.com/stretchr/testify/require"
)
func TestPersistentStorage_UInt32(t *testing.T) {
storage, err := state.NewPersistentStorage(path.Join(t.TempDir(), ".storage"))
require.NoError(t, err)
defer storage.Close()
n, err := storage.UInt32([]byte("unset-value"))
require.NoError(t, err)
require.EqualValues(t, 0, n)
err = storage.SetUInt32([]byte("foo"), 10)
require.NoError(t, err)
n, err = storage.UInt32([]byte("foo"))
require.NoError(t, err)
require.EqualValues(t, 10, n)
}