[management] use peer.Status.LastSeen field to detect stale peer.Status.Connected values (#7268)

management/server/peer/peer.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	log "github.com/sirupsen/logrus"
+	"gorm.io/gorm"
 
 	"github.com/netbirdio/netbird/management/server/util"
 	"github.com/netbirdio/netbird/shared/management/http/api"
@@ -101,6 +102,32 @@ type PeerStatus struct { //nolint:revive
 	RequiresApproval bool
 }
 
+const (
+	// HeartbeatInterval is how often the management instance serving a peer's sync
+	// stream refreshes the peer's LastSeen.
+	HeartbeatInterval = time.Minute
+	// StaleAfter is how long a connected peer may go without a LastSeen refresh before
+	// it reads as disconnected. It spans several heartbeats so one missed refresh does
+	// not disconnect a live peer.
+	StaleAfter = 5 * time.Minute
+)
+
+// IsConnected reports whether a peer stored with the given connected flag and LastSeen
+// counts as connected. A management instance that stops without marking its peers
+// disconnected leaves the flag set, so a peer whose LastSeen is older than StaleAfter
+// reads as disconnected.
+func IsConnected(connected bool, lastSeen time.Time) bool {
+	return connected && time.Since(lastSeen) < StaleAfter
+}
+
+// AfterFind applies IsConnected to every peer loaded through gorm.
+func (p *Peer) AfterFind(*gorm.DB) error {
+	if p.Status != nil {
+		p.Status.Connected = IsConnected(p.Status.Connected, p.Status.LastSeen)
+	}
+	return nil
+}
+
 // Location is a geo location information of a Peer based on public connection IP
 type Location struct {
 	ConnectionIP net.IP `gorm:"serializer:json"` // from grpc peer or reverse proxy headers depends on setup

management/server/peer/peer_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"net/netip"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -164,3 +165,22 @@ func TestPeerCapabilities(t *testing.T) {
 		})
 	}
 }
+
+func TestIsConnected(t *testing.T) {
+	tests := []struct {
+		name      string
+		connected bool
+		lastSeen  time.Time
+		want      bool
+	}{
+		{name: "connected and recently seen", connected: true, lastSeen: time.Now().Add(-time.Minute), want: true},
+		{name: "connected but not seen for longer than StaleAfter", connected: true, lastSeen: time.Now().Add(-StaleAfter - time.Minute)},
+		{name: "connected but never seen", connected: true},
+		{name: "disconnected and recently seen", lastSeen: time.Now()},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, IsConnected(tt.connected, tt.lastSeen))
+		})
+	}
+}