import logging
import os
import sys
def configure_logging() -> None:
"""Configure logging based on LOG_FORMAT environment variable.
If LOG_FORMAT is set, configures the root logger with a StreamHandler
using the specified format string. This must be called before FastMCP
initialization to ensure our configuration takes precedence.
If LOG_FORMAT is not set or is empty, does nothing and lets FastMCP
configure logging with its default settings.
Environment variables:
LOG_FORMAT: Python logging format string (optional)
Examples:
- "%(asctime)s agent %(levelname)s [%(name)s] %(message)s"
- "%(levelname)s: %(message)s"
- "[%(name)s] %(message)s"
Note:
Invalid format strings will cause errors when log records are formatted,
not during initialization. This typically results in ValueError, KeyError,
or AttributeError being raised when logging occurs.
"""
log_format = os.getenv("LOG_FORMAT", "").strip()
# If LOG_FORMAT is not set or empty, do nothing
if not log_format:
return
# Create handler for stderr (same as FastMCP default)
handler = logging.StreamHandler(sys.stderr)
# Create formatter with the specified format string
# This will raise an error if the format string is invalid (fail fast)
formatter = logging.Formatter(log_format)
handler.setFormatter(formatter)
# Configure root logger
# This must be done before FastMCP calls logging.basicConfig()
logging.root.addHandler(handler)
logging.root.setLevel(logging.INFO)
