[client] Add UI client event notifications (#3207)

client/internal/peer/status.go

@@ -7,21 +7,31 @@ import (
 	"sync"
 	"time"
 
+	"github.com/google/uuid"
+	log "github.com/sirupsen/logrus"
 	"golang.org/x/exp/maps"
 	"google.golang.org/grpc/codes"
 	gstatus "google.golang.org/grpc/status"
+	"google.golang.org/protobuf/types/known/timestamppb"
 
 	"github.com/netbirdio/netbird/client/iface/configurer"
 	"github.com/netbirdio/netbird/client/internal/relay"
+	"github.com/netbirdio/netbird/client/proto"
 	"github.com/netbirdio/netbird/management/domain"
 	relayClient "github.com/netbirdio/netbird/relay/client"
 )
 
+const eventQueueSize = 10
+
 type ResolvedDomainInfo struct {
 	Prefixes     []netip.Prefix
 	ParentDomain domain.Domain
 }
 
+type EventListener interface {
+	OnEvent(event *proto.SystemEvent)
+}
+
 // State contains the latest state of a peer
 type State struct {
 	Mux                        *sync.RWMutex
@@ -157,6 +167,10 @@ type Status struct {
 	peerListChangedForNotification bool
 
 	relayMgr *relayClient.Manager
+
+	eventMux     sync.RWMutex
+	eventStreams map[string]chan *proto.SystemEvent
+	eventQueue   *EventQueue
 }
 
 // NewRecorder returns a new Status instance
@@ -164,6 +178,8 @@ func NewRecorder(mgmAddress string) *Status {
 	return &Status{
 		peers:                 make(map[string]State),
 		changeNotify:          make(map[string]chan struct{}),
+		eventStreams:          make(map[string]chan *proto.SystemEvent),
+		eventQueue:            NewEventQueue(eventQueueSize),
 		offlinePeers:          make([]State, 0),
 		notifier:              newNotifier(),
 		mgmAddress:            mgmAddress,
@@ -806,3 +822,112 @@ func (d *Status) notifyAddressChanged() {
 func (d *Status) numOfPeers() int {
 	return len(d.peers) + len(d.offlinePeers)
 }
+
+// PublishEvent adds an event to the queue and distributes it to all subscribers
+func (d *Status) PublishEvent(
+	severity proto.SystemEvent_Severity,
+	category proto.SystemEvent_Category,
+	msg string,
+	userMsg string,
+	metadata map[string]string,
+) {
+	event := &proto.SystemEvent{
+		Id:          uuid.New().String(),
+		Severity:    severity,
+		Category:    category,
+		Message:     msg,
+		UserMessage: userMsg,
+		Metadata:    metadata,
+		Timestamp:   timestamppb.Now(),
+	}
+
+	d.eventMux.Lock()
+	defer d.eventMux.Unlock()
+
+	d.eventQueue.Add(event)
+
+	for _, stream := range d.eventStreams {
+		select {
+		case stream <- event:
+		default:
+			log.Debugf("event stream buffer full, skipping event: %v", event)
+		}
+	}
+
+	log.Debugf("event published: %v", event)
+}
+
+// SubscribeToEvents returns a new event subscription
+func (d *Status) SubscribeToEvents() *EventSubscription {
+	d.eventMux.Lock()
+	defer d.eventMux.Unlock()
+
+	id := uuid.New().String()
+	stream := make(chan *proto.SystemEvent, 10)
+	d.eventStreams[id] = stream
+
+	return &EventSubscription{
+		id:     id,
+		events: stream,
+	}
+}
+
+// UnsubscribeFromEvents removes an event subscription
+func (d *Status) UnsubscribeFromEvents(sub *EventSubscription) {
+	if sub == nil {
+		return
+	}
+
+	d.eventMux.Lock()
+	defer d.eventMux.Unlock()
+
+	if stream, exists := d.eventStreams[sub.id]; exists {
+		close(stream)
+		delete(d.eventStreams, sub.id)
+	}
+}
+
+// GetEventHistory returns all events in the queue
+func (d *Status) GetEventHistory() []*proto.SystemEvent {
+	return d.eventQueue.GetAll()
+}
+
+type EventQueue struct {
+	maxSize int
+	events  []*proto.SystemEvent
+	mutex   sync.RWMutex
+}
+
+func NewEventQueue(size int) *EventQueue {
+	return &EventQueue{
+		maxSize: size,
+		events:  make([]*proto.SystemEvent, 0, size),
+	}
+}
+
+func (q *EventQueue) Add(event *proto.SystemEvent) {
+	q.mutex.Lock()
+	defer q.mutex.Unlock()
+
+	q.events = append(q.events, event)
+
+	if len(q.events) > q.maxSize {
+		q.events = q.events[len(q.events)-q.maxSize:]
+	}
+}
+
+func (q *EventQueue) GetAll() []*proto.SystemEvent {
+	q.mutex.RLock()
+	defer q.mutex.RUnlock()
+
+	return slices.Clone(q.events)
+}
+
+type EventSubscription struct {
+	id     string
+	events chan *proto.SystemEvent
+}
+
+func (s *EventSubscription) Events() <-chan *proto.SystemEvent {
+	return s.events
+}