first commit

server/internal/backup/log_hub.go

@@ -0,0 +1,110 @@
+package backup
+
+import (
+	"sync"
+	"time"
+)
+
+type LogHub struct {
+	mu      sync.RWMutex
+	streams map[uint]*logStreamState
+}
+
+type logStreamState struct {
+	nextSequence int64
+	events       []LogEvent
+	subscribers  map[int]chan LogEvent
+	nextSubID    int
+	completed    bool
+	status       string
+}
+
+func NewLogHub() *LogHub {
+	return &LogHub{streams: make(map[uint]*logStreamState)}
+}
+
+func (h *LogHub) Append(recordID uint, level, message string) LogEvent {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	state := h.ensureState(recordID)
+	state.nextSequence++
+	event := LogEvent{RecordID: recordID, Sequence: state.nextSequence, Level: level, Message: message, Timestamp: time.Now().UTC(), Status: state.status}
+	state.events = append(state.events, event)
+	for _, subscriber := range state.subscribers {
+		select {
+		case subscriber <- event:
+		default:
+		}
+	}
+	return event
+}
+
+func (h *LogHub) Snapshot(recordID uint) []LogEvent {
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	state, ok := h.streams[recordID]
+	if !ok {
+		return nil
+	}
+	result := make([]LogEvent, len(state.events))
+	copy(result, state.events)
+	return result
+}
+
+func (h *LogHub) Subscribe(recordID uint, buffer int) (<-chan LogEvent, func()) {
+	if buffer <= 0 {
+		buffer = 32
+	}
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	state := h.ensureState(recordID)
+	state.nextSubID++
+	id := state.nextSubID
+	channel := make(chan LogEvent, buffer)
+	state.subscribers[id] = channel
+	for _, event := range state.events {
+		channel <- event
+	}
+	cancel := func() {
+		h.mu.Lock()
+		defer h.mu.Unlock()
+		stream, ok := h.streams[recordID]
+		if !ok {
+			return
+		}
+		subscriber, ok := stream.subscribers[id]
+		if !ok {
+			return
+		}
+		delete(stream.subscribers, id)
+		close(subscriber)
+	}
+	return channel, cancel
+}
+
+func (h *LogHub) Complete(recordID uint, status string) {
+	h.mu.Lock()
+	defer h.mu.Unlock()
+	state := h.ensureState(recordID)
+	state.completed = true
+	state.status = status
+	state.nextSequence++
+	event := LogEvent{RecordID: recordID, Sequence: state.nextSequence, Level: "info", Message: "stream completed", Timestamp: time.Now().UTC(), Completed: true, Status: status}
+	state.events = append(state.events, event)
+	for _, subscriber := range state.subscribers {
+		select {
+		case subscriber <- event:
+		default:
+		}
+	}
+}
+
+func (h *LogHub) ensureState(recordID uint) *logStreamState {
+	state, ok := h.streams[recordID]
+	if ok {
+		return state
+	}
+	state = &logStreamState{subscribers: make(map[int]chan LogEvent), status: "running"}
+	h.streams[recordID] = state
+	return state
+}