Fix: Address code review feedback from gemini-code-assist

Python bridge (scripts/mcp/proxysql_mcp_stdio_bridge.py):
- Make log file path configurable via PROXYSQL_MCP_BRIDGE_LOG env var
- Add httpx.RequestError exception handling for network issues
- Fix asyncio.CancelledError not being re-raised (HIGH priority)
- Replace deprecated asyncio.get_event_loop() with get_running_loop()

C++ server (lib/MCP_Endpoint.cpp):
- Refactor handle_tools_call() to reduce code duplication
- Handle string responses directly without calling .dump()
- Single shared wrapping block for all response types

Per review: https://github.com/ProxySQL/proxysql-vec/pull/11

lib/MCP_Endpoint.cpp

@@ -359,26 +359,23 @@ json MCP_JSONRPC_Resource::handle_tools_call(const json& req_json) {
 			mcp_result["isError"] = true;
 			return mcp_result;
 		}
-		// Success - wrap result in MCP-compliant format with content array
-		// Per MCP spec: https://modelcontextprotocol.io/specification/2025-11-25/server/tools
-		json actual_result = response["result"];
-		json mcp_result;
-		mcp_result["content"] = json::array();
-		json text_content;
-		text_content["type"] = "text";
-		text_content["text"] = actual_result.dump(2);  // Pretty-print JSON with 2-space indent
-		mcp_result["content"].push_back(text_content);
-		mcp_result["isError"] = false;
-		return mcp_result;
+		// Success - use the "result" field as the content to be wrapped
+		response = response["result"];
 	}
 
-	// Fallback: wrap response in MCP format (for compatibility with non-standard handlers)
+	// Wrap the response (or the 'result' field) in MCP-compliant format
+	// Per MCP spec: https://modelcontextprotocol.io/specification/2025-11-25/server/tools
 	json mcp_result;
-	mcp_result["content"] = json::array();
 	json text_content;
 	text_content["type"] = "text";
-	text_content["text"] = response.dump(2);
-	mcp_result["content"].push_back(text_content);
+
+	if (response.is_string()) {
+		text_content["text"] = response.get<std::string>();
+	} else {
+		text_content["text"] = response.dump(2);  // Pretty-print JSON with 2-space indent
+	}
+
+	mcp_result["content"] = json::array({text_content});
 	mcp_result["isError"] = false;
 	return mcp_result;
 }

scripts/mcp/proxysql_mcp_stdio_bridge.py

@@ -34,7 +34,9 @@ from datetime import datetime
 import httpx
 
 # Minimal logging to file for debugging
-_log_file = open("/tmp/proxysql_mcp_bridge.log", "a", buffering=1)
+# Log path can be configured via PROXYSQL_MCP_BRIDGE_LOG environment variable
+_log_file_path = os.getenv("PROXYSQL_MCP_BRIDGE_LOG", "/tmp/proxysql_mcp_bridge.log")
+_log_file = open(_log_file_path, "a", buffering=1)
 def _log(msg):
     _log_file.write(f"[{datetime.now().strftime('%H:%M:%S.%f')[:-3]}] {msg}\n")
     _log_file.flush()
@@ -105,6 +107,15 @@ class ProxySQLMCPEndpoint:
                 },
                 "id": request.get("id", "")
             }
+        except httpx.RequestError as e:
+            return {
+                "jsonrpc": "2.0",
+                "error": {
+                    "code": -32002,
+                    "message": f"Request to ProxySQL failed: {e}"
+                },
+                "id": request.get("id", "")
+            }
         except Exception as e:
             return {
                 "jsonrpc": "2.0",
@@ -172,12 +183,14 @@ class StdioMCPServer:
 
                 except json.JSONDecodeError as e:
                     await self._write_error(-32700, f"Parse error: {e}", "")
+                except asyncio.CancelledError:
+                    raise  # Re-raise to allow proper task cancellation
                 except Exception as e:
                     await self._write_error(-32603, f"Internal error: {e}", "")
 
     async def _readline(self) -> Optional[str]:
         """Read a line from stdin."""
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         line = await loop.run_in_executor(None, sys.stdin.readline)
         if not line:
             return None
@@ -185,7 +198,7 @@ class StdioMCPServer:
 
     async def _writeline(self, data: Any):
         """Write JSON data to stdout."""
-        loop = asyncio.get_event_loop()
+        loop = asyncio.get_running_loop()
         output = json.dumps(data, ensure_ascii=False) + "\n"
         _log(f"WRITE stdout: {len(output)} bytes: {repr(output[:200])}")
         await loop.run_in_executor(None, sys.stdout.write, output)