Скачать или смотреть How to Exclude logging.exception from Logfile but Include it in Stdout

Learn how to manage Python logging to exclude specific error messages from your console output while retaining detailed logs in a file. Perfect for maintaining clean stdout with essential error information logged for review!
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This video is based on the question https://stackoverflow.com/q/77873508/ asked by the user 'Mika' ( https://stackoverflow.com/u/22221987/ ) and on the answer https://stackoverflow.com/a/77879020/ provided by the user 'Vinay Sajip' ( https://stackoverflow.com/u/118903/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Managing Python Logging: Excluding logging.exception from Stdout

When working with Python's logging module, you may find yourself in a situation where you want different logging behaviors for your console (stdout) and logfile. For example, you might want to show the short error summaries in the stdout but still log the full traceback in your log files. This separation can make your console output cleaner while preserving detailed error context for debugging later.

The Problem

You want to set up a custom logger in Python that:

Logs full exception traces to a file (using logging.exception).

Shows short error messages in stdout instead of the full traceback.

Does this without redefining the logging levels, allowing for flexibility in configurations.

Below, I will guide you through a straightforward solution to achieve this.

The Solution

To create a logging setup that behaves in this manner, we will utilize Python's built-in logging module along with a custom formatter.

Step 1: Set Up the Logger

We need to create a logger that handles both output types properly. Start by defining our logger, formatting the stdout and log file handlers differently.

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

How It Works

NoExceptionFormatter Class: This custom formatter overrides the formatException method. It is set to return an empty string, so when logger.exception is called, it won’t print the full traceback in stdout.

Log Handlers:

StreamHandler for stdout: This uses NoExceptionFormatter to show only essential error messages.

FileHandler for log files: This applies a standard formatter that includes the full traceback, making it useful for debugging.

Logging Level: We set the logger to DEBUG level, allowing all log messages to be captured while controlling their output format.

Expected Output

When you run the above script, you should see the following behavior:

In stdout:

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

In the generated log file (application.log):

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

Conclusion

By utilizing custom log formatters in Python, you can effectively manage how error messages are presented in different outputs. This allows you to keep your console clean and readable while still having access to detailed logs whenever necessary. By following the code structure and explanations provided, you can easily implement a tailored logging solution for your applications.

If you have any further questions or need additional clarification on logging in Python, feel free to leave a comment below!