++

backend/app/services/simulation_logging.py

@@ -0,0 +1,82 @@
+"""Per-simulation capture of the same logs shown in the backend terminal."""
+
+from __future__ import annotations
+
+import logging
+import threading
+from contextvars import ContextVar
+from pathlib import Path
+
+
+# Context variables are inherited by asyncio tasks, including the concurrent
+# LLM calls created during a simulation. This keeps concurrent simulations from
+# writing each other's records to the same file.
+CURRENT_SIMULATION_ID: ContextVar[str | None] = ContextVar(
+    "current_simulation_id", default=None
+)
+
+PROJECT_LOGS_DIR = Path(__file__).resolve().parents[3] / "logs"
+
+
+class ChineseSimulationFormatter(logging.Formatter):
+    """Readable Chinese metadata while preserving the original message."""
+
+    LEVELS = {
+        "DEBUG": "调试",
+        "INFO": "信息",
+        "WARNING": "警告",
+        "ERROR": "错误",
+        "CRITICAL": "严重错误",
+    }
+
+    def format(self, record: logging.LogRecord) -> str:
+        timestamp = f"{self.formatTime(record, '%Y-%m-%d %H:%M:%S')},{int(record.msecs):03d}"
+        level = self.LEVELS.get(record.levelname, record.levelname)
+        line = f"{timestamp} [模拟日志] [{level}] [{record.name}] {record.getMessage()}"
+        if record.exc_info:
+            line += "\n" + self.formatException(record.exc_info)
+        return line
+
+
+class SimulationLogHandler(logging.Handler):
+    """Write terminal-formatted records to ``logs/<simulation_id>.log``."""
+
+    def __init__(self) -> None:
+        super().__init__(level=logging.INFO)
+        self._write_lock = threading.Lock()
+
+    def emit(self, record: logging.LogRecord) -> None:
+        simulation_id = CURRENT_SIMULATION_ID.get()
+        if not simulation_id:
+            return
+
+        try:
+            PROJECT_LOGS_DIR.mkdir(parents=True, exist_ok=True)
+            path = PROJECT_LOGS_DIR / f"{simulation_id}.log"
+            line = self.format(record)
+            with self._write_lock:
+                with path.open("a", encoding="utf-8") as handle:
+                    handle.write(line + "\n")
+        except Exception:
+            # Logging must never break a simulation if the disk is unavailable.
+            self.handleError(record)
+
+
+def install_simulation_log_handler() -> None:
+    """Install the capture handler once on the process root logger."""
+    root = logging.getLogger()
+    if any(isinstance(handler, SimulationLogHandler) for handler in root.handlers):
+        return
+
+    handler = SimulationLogHandler()
+    handler.setFormatter(ChineseSimulationFormatter())
+    root.addHandler(handler)
+
+
+def bind_simulation(simulation_id: str):
+    """Bind a simulation ID to the current asyncio task."""
+    return CURRENT_SIMULATION_ID.set(simulation_id)
+
+
+def unbind_simulation(token) -> None:
+    CURRENT_SIMULATION_ID.reset(token)