package database import ( "bytes" "crypto/sha512" "encoding/json" "fmt" "strings" "time" "github.com/pkg/errors" "gorm.io/gorm" "gorm.io/gorm/clause" "github.com/Luzifer/go_helpers/v2/backoff" "github.com/Luzifer/twitch-bot/v3/internal/helpers" ) const ( encryptionValidationKey = "encryption-validation" encryptionValidationMinBackoff = 500 * time.Millisecond encryptionValidationTries = 5 ) type ( coreKV struct { Name string `gorm:"primaryKey"` Value string } ) // DeleteCoreMeta removes a core_kv table entry func (c connector) DeleteCoreMeta(key string) error { return errors.Wrap( helpers.RetryTransaction(c.db, func(tx *gorm.DB) error { return tx.Delete(&coreKV{}, "name = ?", key).Error }), "deleting key from database", ) } // ReadCoreMeta reads an entry of the core_kv table specified by // the given `key` and unmarshals it into the `value`. The value must // be a valid variable to `json.NewDecoder(...).Decode(value)` // (pointer to struct, string, int, ...). In case the key does not // exist a check to 'errors.Is(err, sql.ErrNoRows)' will succeed func (c connector) ReadCoreMeta(key string, value any) error { return c.readCoreMeta(key, value, nil) } // StoreCoreMeta stores an entry to the core_kv table soecified by // the given `key`. The value given must be a valid variable to // `json.NewEncoder(...).Encode(value)`. func (c connector) StoreCoreMeta(key string, value any) error { return c.storeCoreMeta(key, value, nil) } // ReadEncryptedCoreMeta works like ReadCoreMeta but decrypts the // stored value before unmarshalling it func (c connector) ReadEncryptedCoreMeta(key string, value any) error { return c.readCoreMeta(key, value, c.DecryptField) } // ResetEncryptedCoreMeta removes all CoreKV entries from the database func (c connector) ResetEncryptedCoreMeta() error { return errors.Wrap( helpers.RetryTransaction(c.db, func(tx *gorm.DB) error { return tx.Delete(&coreKV{}, "value LIKE ?", "U2FsdGVkX1%").Error }), "removing encrypted meta entries", ) } // StoreEncryptedCoreMeta works like StoreCoreMeta but encrypts the // marshalled value before storing it func (c connector) StoreEncryptedCoreMeta(key string, value any) error { return c.storeCoreMeta(key, value, c.EncryptField) } func (c connector) ValidateEncryption() error { validationHasher := sha512.New() fmt.Fprint(validationHasher, c.encryptionSecret) var ( storedHash string validationHash = fmt.Sprintf("%x", validationHasher.Sum(nil)) ) err := backoff.NewBackoff(). WithMaxIterations(encryptionValidationTries). WithMinIterationTime(encryptionValidationMinBackoff). Retry(func() error { return c.ReadEncryptedCoreMeta(encryptionValidationKey, &storedHash) }) switch { case err == nil: if storedHash != validationHash { // Shouldn't happen: When decryption is possible it should match return errors.New("mismatch between expected and stored hash") } return nil case errors.Is(err, ErrCoreMetaNotFound): return errors.Wrap( c.StoreEncryptedCoreMeta(encryptionValidationKey, validationHash), "initializing encryption validation", ) default: return errors.Wrap(err, "reading encryption-validation") } } //revive:disable-next-line:confusing-naming func (c connector) readCoreMeta(key string, value any, processor func(string) (string, error)) (err error) { var data coreKV if err = helpers.Retry(func() error { err = c.db.First(&data, "name = ?", key).Error if errors.Is(err, gorm.ErrRecordNotFound) { return backoff.NewErrCannotRetry(ErrCoreMetaNotFound) } return errors.Wrap(err, "querying core meta table") }); err != nil { return err } if data.Value == "" { return errors.New("empty value returned") } if processor != nil { if data.Value, err = processor(data.Value); err != nil { return errors.Wrap(err, "processing stored value") } } if err := json.NewDecoder(strings.NewReader(data.Value)).Decode(value); err != nil { return errors.Wrap(err, "JSON decoding value") } return nil } //revive:disable-next-line:confusing-naming func (c connector) storeCoreMeta(key string, value any, processor func(string) (string, error)) (err error) { buf := new(bytes.Buffer) if err := json.NewEncoder(buf).Encode(value); err != nil { return errors.Wrap(err, "JSON encoding value") } encValue := strings.TrimSpace(buf.String()) if processor != nil { if encValue, err = processor(encValue); err != nil { return errors.Wrap(err, "processing value to store") } } data := coreKV{Name: key, Value: encValue} return errors.Wrap( helpers.RetryTransaction(c.db, func(tx *gorm.DB) error { return tx.Clauses(clause.OnConflict{ Columns: []clause.Column{{Name: "name"}}, DoUpdates: clause.AssignmentColumns([]string{"value"}), }).Create(data).Error }), "upserting core meta value", ) }