feat(watchdog): implement keepalive mechanism and enhance connection handling

watchdog/connect.go

@@ -1,6 +1,8 @@
 package watchdog
 
 import (
+	"fmt"
+	"super-frpc/postLog"
 	"time"
 )
 
@@ -13,17 +15,32 @@ func Connect(ipaddr string, port int) bool {
 		return false
 	}
 
-	if err := tcpConnect(ipaddr, port); err != nil {
-		return false
+	deadline := time.Now().Add(5 * time.Second)
+	var lastErr error
+	for {
+		if err := tcpConnect(ipaddr, port); err == nil {
+			break
+		} else {
+			lastErr = err
+		}
+
+		if time.Now().After(deadline) {
+			postLog.Error(fmt.Sprintf("[watchdog] failed to connect before timeout: %v", lastErr))
+			return false
+		}
+
+		time.Sleep(200 * time.Millisecond)
 	}
 
 	response, err := sendMsg("watchdogAgentConnectionTest", 3)
 	if err != nil {
+		postLog.Error(fmt.Sprintf("[watchdog] connection test failed: %v", err))
 		Destroy()
 		return false
 	}
 
 	if response != "success" {
+		postLog.Error(fmt.Sprintf("[watchdog] connection test returned unexpected response: %s", response))
 		Destroy()
 		return false
 	}