[Bugfix] 修复连接telnet资产失败，直接退出coco连接的bug (#164)

* [Bugfix] 修复连接telnet资产失败，直接退出coco连接bug

* [Update] 修复ssh/telnet连接失败信息格式展示

coco/connection.py

@@ -48,7 +48,7 @@ class SSHConnection:
         if asset.domain:
             sock = self.get_proxy_sock_v2(asset)
             if not sock:
-                error = 'Connect gateway failed;'
+                error = 'Connect gateway failed.'
                 logger.error(error)
 
         try:
@@ -86,7 +86,8 @@ class SSHConnection:
                 system_user.username, asset.ip, asset.port,
                 password_short, key_fingerprint,
             ))
-            return None, None, error + '\n' + str(e)
+            error += '\r\n' + str(e) if error else str(e)
+            return None, None, error
         return ssh, sock, None
 
     def get_transport(self, asset, system_user):
@@ -166,7 +167,12 @@ class TelnetConnection:
         logger.debug('Get telnet server socket. {}'.format(self.client.user))
         self.sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         self.sock.settimeout(10)
+        try:
             self.sock.connect((self.asset.ip, self.asset.port))
+        except Exception as e:
+            msg = 'Connect telnet server failed. \r\n{}'.format(e)
+            logger.error(msg)
+            return None, msg
         # Send SGA and ECHO options to Telnet Server
         self.sock.send(telnetlib.IAC + telnetlib.DO + telnetlib.SGA)
         self.sock.send(telnetlib.IAC + telnetlib.DO + telnetlib.ECHO)