feat: custom log formatting

Author: zvikagart

README.md

@@ -210,3 +210,9 @@ This will start a web server where you can:
 - View available tools and resources
 - Test tool calls interactively
 - See server logs and responses
+
+## Log Formatting (Optional)
+
+The MCP server supports custom log formatting through the `LOG_FORMAT` environment variable. This allows you to control the format of log messages output by the server.
+**Example Format Strings:** `"%(asctime)s %(levelname)s [%(name)s] %(message)s"`.
+If `LOG_FORMAT` is not set, the server uses FastMCP's default logging configuration.

src/codeocean_mcp_server/logging_config.py

@@ -0,0 +1,43 @@
+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"
+
+    Raises:
+        ValueError: If LOG_FORMAT contains an invalid format string
+    """
+    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)

src/codeocean_mcp_server/server.py

@@ -3,6 +3,7 @@
 from codeocean import CodeOcean
 from mcp.server.fastmcp import FastMCP
 
+from codeocean_mcp_server.logging_config import configure_logging
 from codeocean_mcp_server.tools import (
     capsules,
     computations,
@@ -13,6 +14,7 @@
 
 def main():
     """Run the MCP server."""
+    configure_logging()
     domain = os.getenv("CODEOCEAN_DOMAIN")
     token = os.getenv("CODEOCEAN_TOKEN")
     if not domain or not token: