feat(evpn-bridge): netlink watcher for configuration

Co-authored-by: Vemula Venkatesh <venkatesh.vemula@intel.com>
Co-authored-by: Saikumar Banoth <banoth.saikumar@intel.com>
Co-authored-by: Jambekar Vishakha <vishakha.jambekar@intel.com>
Co-authored-by: Dimitrios Markou <dimitrios.markou@ericsson.com>
Signed-off-by: atulpatel261194 <Atul.Patel@intel.com>

pkg/netlink/eventbus/eventbus.go

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (c) 2022-2023 Intel Corporation, or its subsidiaries.
+
+// Package eventbus handles pub sub
+package eventbus
+
+import (
+	"sync"
+)
+
+// EventBus holds the event bus info
+type EventBus struct {
+	subscribers map[string][]*Subscriber
+	mutex       sync.Mutex
+}
+
+// Subscriber holds the info for each subscriber
+type Subscriber struct {
+	Ch   chan interface{}
+	Quit chan struct{}
+}
+
+// NewEventBus initializes an EventBus object
+func NewEventBus() *EventBus {
+	return &EventBus{
+		subscribers: make(map[string][]*Subscriber),
+	}
+}
+
+// Subscribe api provides registration of a subscriber to the given eventType
+func (e *EventBus) Subscribe(eventType string) *Subscriber {
+	e.mutex.Lock()
+	defer e.mutex.Unlock()
+
+	subscriber := &Subscriber{
+		Ch:   make(chan interface{}),
+		Quit: make(chan struct{}),
+	}
+
+	e.subscribers[eventType] = append(e.subscribers[eventType], subscriber)
+
+	return subscriber
+}
+
+// Publish api notifies the subscribers with certain eventType
+func (e *EventBus) Publish(eventType string, data interface{}) {
+	e.mutex.Lock()
+	defer e.mutex.Unlock()
+
+	subscribers, ok := e.subscribers[eventType]
+	if !ok {
+		return
+	}
+
+	for _, sub := range subscribers {
+		sub.Ch <- data
+	}
+}
+
+// Unsubscribe closes all subscriber channels and empties the subscriber map.
+func (e *EventBus) Unsubscribe() {
+	e.mutex.Lock()
+	defer e.mutex.Unlock()
+
+	for eventName, subs := range e.subscribers {
+		for _, sub := range subs {
+			close(sub.Ch) // Close each channel
+		}
+		delete(e.subscribers, eventName) // Remove the entry from the map
+	}
+}