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