Fix: log duplication when json_logs is enabled

litellm-proxy-extras/litellm_proxy_extras/_logging.py

@@ -1,12 +1,40 @@
+import json
 import logging
+import os
+from datetime import datetime
+
+
+class JsonFormatter(logging.Formatter):
+    def formatTime(self, record, datefmt=None):
+        dt = datetime.fromtimestamp(record.created)
+        return dt.isoformat()
+
+    def format(self, record):
+        json_record = {
+            "message": record.getMessage(),
+            "level": record.levelname,
+            "timestamp": self.formatTime(record),
+        }
+        if record.exc_info:
+            json_record["stacktrace"] = self.formatException(record.exc_info)
+        return json.dumps(json_record)
+
+
+def _is_json_enabled():
+    try:
+        import litellm
+        return getattr(litellm, 'json_logs', False)
+    except (ImportError, AttributeError):
+        return os.getenv("JSON_LOGS", "false").lower() == "true"
+
 
-# Set up package logger
 logger = logging.getLogger("litellm_proxy_extras")
-if not logger.handlers:  # Only add handler if none exists
+
+if not logger.handlers:
     handler = logging.StreamHandler()
-    formatter = logging.Formatter(
-        "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
-    )
-    handler.setFormatter(formatter)
+    if _is_json_enabled():
+        handler.setFormatter(JsonFormatter())
+    else:
+        handler.setFormatter(logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s"))
     logger.addHandler(handler)
     logger.setLevel(logging.INFO)

litellm/_logging.py

@@ -166,6 +166,66 @@ def _initialize_loggers_with_handler(handler: logging.Handler):
         lg.propagate = False  # prevent bubbling to parent/root
 
 
+def _get_uvicorn_json_log_config():
+    """
+    Generate a uvicorn log_config dictionary that applies JSON formatting to all loggers.
+
+    This ensures that uvicorn's access logs, error logs, and all application logs
+    are formatted as JSON when json_logs is enabled.
+    """
+    json_formatter_class = "litellm._logging.JsonFormatter"
+
+    # Use the module-level log_level variable for consistency
+    uvicorn_log_level = log_level.upper()
+
+    log_config = {
+        "version": 1,
+        "disable_existing_loggers": False,
+        "formatters": {
+            "json": {
+                "()": json_formatter_class,
+            },
+            "default": {
+                "()": json_formatter_class,
+            },
+            "access": {
+                "()": json_formatter_class,
+            },
+        },
+        "handlers": {
+            "default": {
+                "formatter": "json",
+                "class": "logging.StreamHandler",
+                "stream": "ext://sys.stdout",
+            },
+            "access": {
+                "formatter": "access",
+                "class": "logging.StreamHandler",
+                "stream": "ext://sys.stdout",
+            },
+        },
+        "loggers": {
+            "uvicorn": {
+                "handlers": ["default"],
+                "level": uvicorn_log_level,
+                "propagate": False,
+            },
+            "uvicorn.error": {
+                "handlers": ["default"],
+                "level": uvicorn_log_level,
+                "propagate": False,
+            },
+            "uvicorn.access": {
+                "handlers": ["access"],
+                "level": uvicorn_log_level,
+                "propagate": False,
+            },
+        },
+    }
+
+    return log_config
+
+
 def _turn_on_json():
     """
     Turn on JSON logging

litellm/proxy/proxy_cli.py

@@ -127,6 +127,7 @@ def _get_default_unvicorn_init_args(
         Get the arguments for `uvicorn` worker
         """
         import litellm
+        from litellm._logging import _get_uvicorn_json_log_config
 
         uvicorn_args = {
             "app": "litellm.proxy.proxy_server:app",
@@ -137,8 +138,8 @@ def _get_default_unvicorn_init_args(
             print(f"Using log_config: {log_config}")  # noqa
             uvicorn_args["log_config"] = log_config
         elif litellm.json_logs:
-            print("Using json logs. Setting log_config to None.")  # noqa
-            uvicorn_args["log_config"] = None
+            # Use JSON log config for uvicorn to ensure all logs (including exceptions) are JSON
+            uvicorn_args["log_config"] = _get_uvicorn_json_log_config()
         if keepalive_timeout is not None:
             uvicorn_args["timeout_keep_alive"] = keepalive_timeout
         return uvicorn_args