Adding approval process

pkg/pubsub/pubsub.go

@@ -0,0 +1,51 @@
+package pubsub
+
+import "sync"
+
+type Pubsub struct {
+	mu     sync.RWMutex
+	subs   map[string][]chan string
+	closed bool
+}
+
+func New() *Pubsub {
+	ps := Pubsub{}
+	ps.subs = make(map[string][]chan string)
+	return &ps
+}
+
+func (ps *Pubsub) Publish(topic string, msg string) {
+	ps.mu.RLock()
+	defer ps.mu.RUnlock()
+
+	if ps.closed {
+		return
+	}
+
+	for _, ch := range ps.subs[topic] {
+		ch <- msg
+	}
+}
+
+func (ps *Pubsub) Subscribe(topic string) <-chan string {
+	ps.mu.Lock()
+	defer ps.mu.Unlock()
+
+	ch := make(chan string, 1)
+	ps.subs[topic] = append(ps.subs[topic], ch)
+	return ch
+}
+
+func (ps *Pubsub) Close() {
+	ps.mu.Lock()
+	defer ps.mu.Unlock()
+
+	if !ps.closed {
+		ps.closed = true
+		for _, subs := range ps.subs {
+			for _, ch := range subs {
+				close(ch)
+			}
+		}
+	}
+}