Events package update

Signed-off-by: Valery Piashchynski <[email protected]>

1 files changed, 129 insertions, 0 deletions

diff --git a/events/eventsbus.go b/events/eventsbus.go
new file mode 100644
index 00000000..79f5babd
--- /dev/null
+++ b/events/eventsbus.go
@@ -0,0 +1,129 @@
+package events
+
+import (
+	"fmt"
+	"sync"
+)
+
+type sub struct {
+	pattern string
+	w       *wildcard
+	events  chan<- Event
+}
+
+type eventsBus struct {
+	sync.RWMutex
+	subscribers  sync.Map
+	internalEvCh chan Event
+	stop         chan struct{}
+}
+
+func newEventsBus() *eventsBus {
+	return &eventsBus{
+		internalEvCh: make(chan Event, 100),
+		stop:         make(chan struct{}),
+	}
+}
+
+/*
+http.* <-
+*/
+
+// SubscribeAll for all RR events
+// returns subscriptionID
+func (eb *eventsBus) SubscribeAll(subID string, ch chan<- Event) error {
+	return eb.subscribe(subID, "*", ch)
+}
+
+// SubscribeP pattern like "pluginName.EventType"
+func (eb *eventsBus) SubscribeP(subID string, pattern string, ch chan<- Event) error {
+	return eb.subscribe(subID, pattern, ch)
+}
+
+func (eb *eventsBus) Unsubscribe(subID string) {
+	eb.subscribers.Delete(subID)
+}
+func (eb *eventsBus) UnsubscribeP(subID, pattern string) {
+	if sb, ok := eb.subscribers.Load(subID); ok {
+		eb.Lock()
+		defer eb.Unlock()
+
+		sbArr := sb.([]*sub)
+
+		for i := 0; i < len(sbArr); i++ {
+			if sbArr[i].pattern == pattern {
+				sbArr[i] = sbArr[len(sbArr)-1]
+				sbArr = sbArr[:len(sbArr)-1]
+				// replace with new array
+				eb.subscribers.Store(subID, sbArr)
+				return
+			}
+		}
+	}
+}
+
+// Send sends event to the events bus
+func (eb *eventsBus) Send(ev Event) {
+	eb.internalEvCh <- ev
+}
+
+func (eb *eventsBus) subscribe(subID string, pattern string, ch chan<- Event) error {
+	eb.Lock()
+	defer eb.Unlock()
+	w, err := newWildcard(pattern)
+	if err != nil {
+		return err
+	}
+
+	if sb, ok := eb.subscribers.Load(subID); ok {
+		// at this point we are confident that sb is a []*sub type
+		subArr := sb.([]*sub)
+		subArr = append(subArr, &sub{
+			pattern: pattern,
+			w:       w,
+			events:  ch,
+		})
+
+		eb.subscribers.Store(subID, subArr)
+
+		return nil
+	}
+
+	subArr := make([]*sub, 0, 5)
+	subArr = append(subArr, &sub{
+		pattern: pattern,
+		w:       w,
+		events:  ch,
+	})
+
+	eb.subscribers.Store(subID, subArr)
+
+	return nil
+}
+
+func (eb *eventsBus) handleEvents() {
+	for { //nolint:gosimple
+		select {
+		case ev := <-eb.internalEvCh:
+			//
+			wc := fmt.Sprintf("%s.%s", ev.Plugin(), ev.Type().String())
+
+			eb.subscribers.Range(func(key, value interface{}) bool {
+				vsub := value.([]*sub)
+
+				for i := 0; i < len(vsub); i++ {
+					if vsub[i].w.match(wc) {
+						select {
+						case vsub[i].events <- ev:
+							return true
+						default:
+							return true
+						}
+					}
+				}
+
+				return true
+			})
+		}
+	}
+}