NET-1782: Fetch Node Connection Status from metrics (#3237)

* add live status of node

* handle static node status

* add public IP field to server configuration

* get public Ip from config

* improve node status logic

* improvise status check

* use only checkin status on old nodes

---------

Co-authored-by: the_aceix <aceixsmartx@gmail.com>

models/node.go

@@ -11,6 +11,19 @@ import (
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 )
 
+type NodeStatus string
+
+const (
+	OnlineSt  NodeStatus = "online"
+	OfflineSt NodeStatus = "offline"
+	WarningSt NodeStatus = "warning"
+	ErrorSt   NodeStatus = "error"
+	UnKnown   NodeStatus = "unknown"
+)
+
+// LastCheckInThreshold - if node's checkin more than this threshold,then node is declared as offline
+const LastCheckInThreshold = time.Minute * 10
+
 const (
 	// NODE_SERVER_NAME - the default server name
 	NODE_SERVER_NAME = "netmaker"
@@ -103,6 +116,7 @@ type Node struct {
 	IsStatic          bool                `json:"is_static"`
 	IsUserNode        bool                `json:"is_user_node"`
 	StaticNode        ExtClient           `json:"static_node"`
+	Status            NodeStatus          `json:"node_status"`
 }
 
 // LegacyNode - legacy struct for node model