jd-opensource/joyagent-jdgenie · error · Exception

网络连接失败

Error message

网络连接失败: {str(e)}

What it means

Raised by `_sse_connection` when the underlying HTTP/SSE transport raises a network-class error (per `_is_network_error`), such as connection refused, DNS failure, or timeout while opening the SSE stream. The client wraps it into a friendlier message but preserves the cause via `from e`.

Solutions

1. Confirm the MCP server is running and reachable: curl/telnet the server_url host and port
2. Check server_url for typos (scheme, host, port) in the client configuration
3. Check firewall/proxy rules allow the connection and long-lived streaming responses
4. If it's flaky infrastructure, retry with backoff; the finally-block cleans up the half-open connection

Example fix

// before
client = SseClient(server_url="http://localhost:8080")  # server actually on 8000
// after
client = SseClient(server_url="http://localhost:8000")

import socket
host, port = parse_host_port(server_url)
socket.create_connection((host, port), timeout=3).close()  # raises if unreachable

def server_reachable(url: str) -> bool:
    try:
        host, port = parse_host_port(url)
        socket.create_connection((host, port), timeout=3).close()
        return True
    except OSError:
        return False

for attempt in range(3):
    try:
        return await client.ping_server()
    except Exception as e:
        if "网络连接失败" in str(e):
            await asyncio.sleep(2 ** attempt)
        else:
            raise

When it happens

Trigger: ping_server, list_tools, or call_tool attempts an SSE connection while the server host is unreachable: wrong port, server down, DNS failure, firewall, or TLS/network timeout.

Common situations: MCP server not started; server_url typo (wrong host/port/scheme); docker network isolation; proxy blocking long-lived SSE connections; VPN down.

Understand the failure class

Background: ECONNREFUSED and "connection refused" / "could not connect to server" errors: what they mean and how to fix them — this error's family across 44 libraries.

Related errors

• sse listener failed
• 调用接口" + url + "失败:" + response.message()
• sse nl2sql failed:
• 返回结果为空！
• Network response was not ok

AI-assisted analysis of jd-opensource/joyagent-jdgenie@2417e0b8b6 (2026-09-08). Data as JSON: /api/errors/ce2d47b20df7b0f5. Report an issue: GitHub.

Appendix: source

Thrown at genie-client/app/client.py:149

            # 创建客户端会话
            self._session_context = ClientSession(*streams)
            session = await self._session_context.__aenter__()
            logger.debug(f"[{connection_id}] 客户端会话已创建")

            # 初始化会话，可能触发认证验证
            await session.initialize()
            logger.info(f"[{connection_id}] SSE连接建立成功")

            yield session

        except Exception as e:
            # 根据异常类型进行不同的处理
            if self._is_authentication_error(e):
                logger.error(f"[{connection_id}] 认证失败 - 401 未授权")
                raise Exception("认证失败 - 无效的凭据") from e
            elif self._is_network_error(e):
                logger.error(f"[{connection_id}] 网络连接失败: {str(e)}")
                raise Exception(f"网络连接失败: {str(e)}") from e
            else:
                logger.error(f"[{connection_id}] SSE连接失败: {str(e)}")
                raise
        finally:
            # 确保资源被正确清理
            await self._cleanup_connection(connection_id)

    @staticmethod
    def _is_authentication_error(exception: Exception) -> bool:
        """
        检查异常是否为认证错误 (401 Unauthorized)

        Args:
            exception: 待检查的异常对象

        Returns:
            bool: 如果是认证错误返回True，否则返回False
        """

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