函数计算使用模板访问mysql 报错502如何解决？

函数计算使用模板访问mysql 报错502如何解决？
{
"errorMessage": "Expecting value: line 1 column 1 (char 0)",
"errorType": "JSONDecodeError",
"stackTrace": [
[
"File \"/var/fc/runtime/python3.10/bootstrap.py\"",
"line 549",
"in wsgi_wrapper",
"body = request_handler(environ, start_response)"
],
[
"File \"/code/index.py\"",
"line 55",
"in handler",
"request_body_json=json.loads(request_body)"
],
[
"File \"/var/fc/lang/python3.10/lib/python3.10/json/init.py\"",
"line 346",
"in loads",
"return _default_decoder.decode(s)"
],
[
"File \"/var/fc/lang/python3.10/lib/python3.10/json/decoder.py\"",
"line 337",
"in decode",
"obj, end = self.raw_decode(s, idx=_w(s, 0).end())"
],
[
"File \"/var/fc/lang/python3.10/lib/python3.10/json/decoder.py\"",
"line 355",
"in raw_decode",
"raise JSONDecodeError(\"Expecting value\", s, err.value) from None"
]
]
}