Complete refactor to new grpc control plane and only http proxy for carts (#4)

Co-authored-by: matst80 <mats.tornberg@gmail.com>
Reviewed-on: https://git.tornberg.me/mats/go-cart-actor/pulls/4
Co-authored-by: Mats Törnberg <mats@tornberg.me>
Co-committed-by: Mats Törnberg <mats@tornberg.me>

pkg/actor/disk_storage.go

@@ -0,0 +1,137 @@
+package actor
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+)
+
+type QueueEvent struct {
+	TimeStamp time.Time
+	Message   proto.Message
+}
+
+type DiskStorage[V any] struct {
+	*StateStorage
+	path  string
+	done  chan struct{}
+	queue *sync.Map // map[uint64][]QueueEvent
+}
+
+type LogStorage[V any] interface {
+	LoadEvents(id uint64, grain Grain[V]) error
+	AppendEvent(id uint64, msg ...proto.Message) error
+}
+
+func NewDiskStorage[V any](path string, registry MutationRegistry) *DiskStorage[V] {
+	return &DiskStorage[V]{
+		StateStorage: NewState(registry),
+		path:         path,
+		done:         make(chan struct{}),
+	}
+}
+
+func (s *DiskStorage[V]) SaveLoop(duration time.Duration) {
+	s.queue = &sync.Map{}
+	ticker := time.NewTicker(duration)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-s.done:
+			s.save()
+			return
+		case <-ticker.C:
+			s.save()
+		}
+	}
+}
+
+func (s *DiskStorage[V]) save() {
+	carts := 0
+	lines := 0
+	s.queue.Range(func(key, value any) bool {
+		id := key.(uint64)
+		path := s.logPath(id)
+		fh, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Printf("failed to open event log file: %v", err)
+			return true
+		}
+		defer fh.Close()
+
+		if qe, ok := value.([]QueueEvent); ok {
+			for _, msg := range qe {
+				if err := s.Append(fh, msg.Message, msg.TimeStamp); err != nil {
+					log.Printf("failed to append event to log file: %v", err)
+				}
+				lines++
+			}
+		}
+		carts++
+		s.queue.Delete(id)
+		return true
+	})
+	if lines > 0 {
+		log.Printf("Appended %d carts and %d lines to disk", carts, lines)
+	}
+}
+
+func (s *DiskStorage[V]) logPath(id uint64) string {
+	return filepath.Join(s.path, fmt.Sprintf("%d.events.log", id))
+}
+
+func (s *DiskStorage[V]) LoadEvents(id uint64, grain Grain[V]) error {
+	path := s.logPath(id)
+	if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) {
+		// No log -> nothing to replay
+		return nil
+	}
+
+	fh, err := os.Open(path)
+	if err != nil {
+		return fmt.Errorf("open replay file: %w", err)
+	}
+	defer fh.Close()
+	return s.Load(fh, func(msg proto.Message) {
+		s.registry.Apply(grain, msg)
+	})
+}
+
+func (s *DiskStorage[V]) Close() {
+	s.save()
+	close(s.done)
+}
+
+func (s *DiskStorage[V]) AppendEvent(id uint64, msg ...proto.Message) error {
+	if s.queue != nil {
+		queue := make([]QueueEvent, 0)
+		data, found := s.queue.Load(id)
+		if found {
+			queue = data.([]QueueEvent)
+		}
+		for _, m := range msg {
+			queue = append(queue, QueueEvent{Message: m, TimeStamp: time.Now()})
+		}
+		s.queue.Store(id, queue)
+		return nil
+	} else {
+		path := s.logPath(id)
+		fh, err := os.OpenFile(path, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err != nil {
+			log.Printf("failed to open event log file: %v", err)
+			return err
+		}
+		defer fh.Close()
+		for _, m := range msg {
+			err = s.Append(fh, m, time.Now())
+		}
+		return err
+	}
+
+}