From 275aab9d42dbffab36809932e8c8aa2823962809 Mon Sep 17 00:00:00 2001
From: Willem Jiang <willem.jiang@gmail.com>
Date: Thu, 1 Jan 2026 09:32:42 +0800
Subject: [PATCH] fix(log): Enable the logging level  when enabling the DEBUG
 environment variable (#793)

---
 server.py         | 12 +++++++++---
 src/server/app.py | 13 +++++++++++++
 src/workflow.py   |  3 +++
 3 files changed, 25 insertions(+), 3 deletions(-)

diff --git a/server.py b/server.py
index 8091c44..a05d3b0 100644
--- a/server.py
+++ b/server.py
@@ -79,12 +79,18 @@ if __name__ == "__main__":
     if args.reload:
         reload = True
 
+    # Check for DEBUG environment variable to override log level
+    if os.getenv("DEBUG", "").lower() in ("true", "1", "yes"):
+        log_level = "debug"
+    else:
+        log_level = args.log_level
+
     try:
         logger.info(f"Starting DeerFlow API server on {args.host}:{args.port}")
-        logger.info(f"Log level: {args.log_level.upper()}")
+        logger.info(f"Log level: {log_level.upper()}")
         
         # Set the appropriate logging level for the src package if debug is enabled
-        if args.log_level.lower() == "debug":
+        if log_level.lower() == "debug":
             logging.getLogger("src").setLevel(logging.DEBUG)
             logging.getLogger("langchain").setLevel(logging.DEBUG)
             logging.getLogger("langgraph").setLevel(logging.DEBUG)
@@ -95,7 +101,7 @@ if __name__ == "__main__":
             host=args.host,
             port=args.port,
             reload=reload,
-            log_level=args.log_level,
+            log_level=log_level,
         )
     except Exception as e:
         logger.error(f"Failed to start server: {str(e)}")
diff --git a/src/server/app.py b/src/server/app.py
index bb334b7..e541d28 100644
--- a/src/server/app.py
+++ b/src/server/app.py
@@ -9,6 +9,19 @@ import os
 from typing import Annotated, Any, List, Optional, cast
 from uuid import uuid4
 
+# Load environment variables from .env file FIRST
+# This must happen before checking DEBUG environment variable
+from dotenv import load_dotenv
+load_dotenv()
+
+# Configure logging based on DEBUG environment variable
+# This must happen early, before other modules are imported
+_debug_mode = os.getenv("DEBUG", "").lower() in ("true", "1", "yes")
+if _debug_mode:
+    logging.getLogger("src").setLevel(logging.DEBUG)
+    logging.getLogger("langchain").setLevel(logging.DEBUG)
+    logging.getLogger("langgraph").setLevel(logging.DEBUG)
+
 from fastapi import FastAPI, HTTPException, Query, UploadFile
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import Response, StreamingResponse
diff --git a/src/workflow.py b/src/workflow.py
index 41ff5b3..0bf470f 100644
--- a/src/workflow.py
+++ b/src/workflow.py
@@ -16,7 +16,10 @@ logging.basicConfig(
 
 def enable_debug_logging():
     """Enable debug level logging for more detailed execution information."""
+    # Must also set root logger level to allow DEBUG messages to propagate
     logging.getLogger("src").setLevel(logging.DEBUG)
+    logging.getLogger("langchain").setLevel(logging.DEBUG)
+    logging.getLogger("langgraph").setLevel(logging.DEBUG)
 
 
 logger = logging.getLogger(__name__)