Initial commit

server/internal/httpapi/events.go

@@ -0,0 +1,65 @@
+package httpapi
+
+import (
+	"encoding/json"
+	"sync"
+	"time"
+)
+
+type queueEvent struct {
+	ProjectID string    `json:"project_id"`
+	Revision  int64     `json:"revision"`
+	Type      string    `json:"type"`
+	At        time.Time `json:"at"`
+}
+
+// eventPublisher is the boundary for replacing the per-process fallback with
+// a shared Redis-backed bus when Kubernetes runs multiple API pods. The
+// current MVP intentionally keeps the in-memory implementation local.
+type eventPublisher interface {
+	subscribe(projectID string) (<-chan []byte, func())
+	publish(event queueEvent)
+}
+
+type eventHub struct {
+	mu          sync.RWMutex
+	subscribers map[string]map[chan []byte]struct{}
+}
+
+func newEventHub() *eventHub {
+	return &eventHub{subscribers: make(map[string]map[chan []byte]struct{})}
+}
+
+func (h *eventHub) subscribe(projectID string) (<-chan []byte, func()) {
+	ch := make(chan []byte, 8)
+	h.mu.Lock()
+	if h.subscribers[projectID] == nil {
+		h.subscribers[projectID] = make(map[chan []byte]struct{})
+	}
+	h.subscribers[projectID][ch] = struct{}{}
+	h.mu.Unlock()
+	return ch, func() {
+		h.mu.Lock()
+		delete(h.subscribers[projectID], ch)
+		if len(h.subscribers[projectID]) == 0 {
+			delete(h.subscribers, projectID)
+		}
+		h.mu.Unlock()
+	}
+}
+
+func (h *eventHub) publish(event queueEvent) {
+	body, err := json.Marshal(event)
+	if err != nil {
+		return
+	}
+	h.mu.RLock()
+	defer h.mu.RUnlock()
+	for ch := range h.subscribers[event.ProjectID] {
+		select {
+		case ch <- body:
+		default:
+			// A slow client can recover from the authoritative snapshot/revision.
+		}
+	}
+}