database/db.go (view raw)
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package database import ( "bytes" "errors" "fmt" "math" "path" "strconv" "time" "git.icyphox.sh/paprika/config" "github.com/dgraph-io/badger/v3" ) // Use this as a global DB handle. var DB database type database struct { *badger.DB } // see: https://dgraph.io/docs/badger/get-started/#garbage-collection func gc() { ticker := time.NewTicker(5 * time.Minute) defer ticker.Stop() for range ticker.C { again: err := DB.DB.RunValueLogGC(0.7) if err == nil { goto again } } panic("Unreachable!") } func Open() (*badger.DB, error) { db, err := badger.Open( badger.DefaultOptions(path.Join(config.C.DbPath, "badger")), ) if err != nil { return nil, err } go gc() return db, nil } // Wrapper function to simplify setting a key/val // in badger. func (d *database) Set(key, val []byte) error { err := d.Update(func(txn *badger.Txn) error { err := txn.Set(key, val) return err }) return err } // Wrapper function to simplify setting a key/val with a duration. // see Set func (d *database) SetWithTTL(key, val []byte, duration time.Duration) error { err := d.Update(func(txn *badger.Txn) error { err := txn.SetEntry(badger.NewEntry(key, val).WithTTL(duration)) return err }) return err } // Wrapper function to simplify getting a key from badger. func (d *database) Get(key []byte) ([]byte, error) { var val []byte err := d.View(func(txn *badger.Txn) error { item, err := txn.Get(key) if err != nil { return err } err = item.Value(func(v []byte) error { val = v return nil }) return err }) if err != nil { return nil, err } return val, nil } type KVPair struct { a, b []byte } // Wrapper function to simplify getting a range of keys with a given prefix. func (d *database) GetRange(prefix []byte) ([]KVPair, error) { var vals []KVPair err := d.View(func(txn *badger.Txn) error { iter := txn.NewIterator(badger.DefaultIteratorOptions) defer iter.Close() for iter.Seek(prefix); iter.ValidForPrefix(prefix); iter.Next() { item := iter.Item() var pair KVPair key := item.Key() pair.a = key err := item.Value(func(val []byte) error { pair.b = val return nil }) if err != nil { return err } vals = append(vals, pair) } return nil }) if err != nil { return nil, err } return vals, nil } // Key delete wrapper. Returns deleted Value func (d *database) Delete(key []byte) ([]byte, error) { var val []byte err := d.DB.Update(func(txn *badger.Txn) error { item, err := txn.Get(key) if err != nil { return err } err = item.Value(func(v []byte) error { val = v return nil }) return txn.Delete(key) }) return val, err } var NumTooBig = errors.New("Number Too Big") var InvalidNumber = errors.New("Invalid Number") // encode number so it sorts lexicographically, while being semi readable. func EncodeNumber(n int) ([]byte, error) { neg := false num := n if n < 0 { neg = true num = -num } digits := int(math.Trunc(math.Log10(float64(num))))+1 if digits > 93 { return []byte{}, NumTooBig } if !neg { lenCode := 33 + digits return []byte(fmt.Sprintf("%c %d", lenCode, n)), nil } else { lenCode := 127 - digits return []byte(fmt.Sprintf("!%c %d", lenCode, n)), nil } } func ToKey(prefix, key string) []byte { return []byte(fmt.Sprintf("%s/%s", prefix, key)) } // encode number so it sorts lexicographically, while being semi readable. func DecodeNumber(n []byte) (int, error) { if len(n) < 3 { return 0, InvalidNumber } // No digit padding if n[0] < 33 || n[0] > 126 { return 0, InvalidNumber } num := bytes.SplitN(n, []byte{' '}, 2) if len(num) != 2 { return 0, InvalidNumber } number, err := strconv.Atoi(string(num[1])) if err != nil { return number, err } if n[0] == '!' { return -number, nil } else { return number, nil } } |