How to Prevent Python Tornado from Logging to STDOUT/Console

Learn how to disable logging to STDOUT in Python Tornado, ensuring that your log statements are handled only by a rotating file logger.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to prevent Python Tornado from logging to stdout/console?

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Prevent Python Tornado from Logging to STDOUT/Console

In the world of programming, logging is an essential part of monitoring and debugging applications. However, when working with frameworks like Python Tornado, you might find that log messages are being sent to both your specified log files and the console. This dual logging can be cumbersome and unnecessary, especially when you prefer to handle logging exclusively through a file.

If you're using Python 3.8 and run into this issue on an Ubuntu 18.04 system, you're not alone. Below, we'll explore a clear and effective solution to prevent Tornado from logging to STDOUT or your console, allowing you to focus solely on your log files.

Understanding the Problem

By default, Python's logging module might be configured to stream log messages to the console. Specifically, when you start an IDE like Spyder, it can automatically attach a StreamHandler to the tornado logger. This behavior can lead to duplicates in logging—both in your specified log file and in the console output.

To maintain a clean logging setup, you need to replace the StreamHandler with a NullHandler.

Step-by-Step Solution

1. Set Up the Logging System

First, you will need to import the necessary modules and set up your logger as you usually would. Here’s a basic setup that includes a rotating file handler for your logs:

[[See Video to Reveal this Text or Code Snippet]]

2. Disable the StreamHandler

Since the StreamHandler is often attached automatically, you will have to explicitly clear any existing handlers from the tornado logger and replace them with a NullHandler. Here’s how to do this:

[[See Video to Reveal this Text or Code Snippet]]

3. Final Integration

Now, integrate all these steps into your main function. Here's how the complete script might look:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, you effectively prevent Python Tornado from sending logs to STDOUT. Your application will now log exclusively to your designated rotating file, keeping your console clean and focused on relevant outputs.

This setup can significantly enhance your productivity and reduce distractions caused by unwanted console messages. If you encounter any issues, feel free to revisit the code and ensure that the handlers are correctly set up.

With this guide, you should now be able to maintain a clean logging approach in your Tornado applications. Happy coding!