99 lines
1.9 KiB
Go
99 lines
1.9 KiB
Go
package actor
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import (
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"bufio"
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"encoding/json"
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"errors"
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"io"
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"time"
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"google.golang.org/protobuf/proto"
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)
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type StateStorage struct {
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registry MutationRegistry
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}
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type StorageEvent struct {
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Type string `json:"type"`
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TimeStamp time.Time `json:"timestamp"`
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Mutation proto.Message `json:"mutation"`
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}
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type rawEvent struct {
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Type string `json:"type"`
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TimeStamp time.Time `json:"timestamp"`
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Mutation json.RawMessage `json:"mutation"`
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}
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func NewState(registry MutationRegistry) *StateStorage {
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return &StateStorage{
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registry: registry,
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}
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}
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var ErrUnknownType = errors.New("unknown type")
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func (s *StateStorage) Load(r io.Reader, onMessage func(msg proto.Message, timeStamp time.Time)) error {
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var err error
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var evt *StorageEvent
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scanner := bufio.NewScanner(r)
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for err == nil {
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evt, err = s.Read(scanner)
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if err == nil {
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onMessage(evt.Mutation, evt.TimeStamp)
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}
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}
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if err == io.EOF {
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return nil
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}
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return err
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}
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func (s *StateStorage) Append(io io.Writer, mutation proto.Message, timeStamp time.Time) error {
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typeName, ok := s.registry.GetTypeName(mutation)
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if !ok {
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return ErrUnknownType
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}
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event := &StorageEvent{
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Type: typeName,
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TimeStamp: timeStamp,
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Mutation: mutation,
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}
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jsonBytes, err := json.Marshal(event)
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if err != nil {
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return err
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}
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if _, err := io.Write(jsonBytes); err != nil {
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return err
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}
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io.Write([]byte("\n"))
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return nil
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}
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func (s *StateStorage) Read(r *bufio.Scanner) (*StorageEvent, error) {
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var event rawEvent
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if r.Scan() {
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b := r.Bytes()
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err := json.Unmarshal(b, &event)
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if err != nil {
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return nil, err
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}
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typeName := event.Type
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mutation, ok := s.registry.Create(typeName)
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if !ok {
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return nil, ErrUnknownType
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}
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if err := json.Unmarshal(event.Mutation, mutation); err != nil {
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return nil, err
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}
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return &StorageEvent{
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Type: typeName,
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TimeStamp: event.TimeStamp,
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Mutation: mutation,
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}, r.Err()
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}
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return nil, io.EOF
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}
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