How To Write Logs To A File With Python?

Better Stack Team

Updated on February 1, 2023

If you are new to logging in Python, please feel free to start with our Introduction to Python logging to get started smoothly. Otherwise, here is how to write logs to a file in Python:

Using Basic Configuration

You can use basic config. If you configure the attribute filename, logs will be automatically saved to the file you specify. You can also configure the attribute filemode. Setting the value to w will overwrite the file after every entry.

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import logging

logging.basicConfig(filename="logs.log", filemode="w", format="%(name)s -> %(levelname)s: %(message)s")

logging.warning("warning")

OUTPUT
root -> WARNING: warning

Using Provided Classes

You can also use the provided classes - loggers and handlers:

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logger = logging.getLogger(__name__)
FileOutputHandler = logging.FileHandler('logs.log')

logger.addHandler(FileOutputHandler)

logger.warning("Warning.")

You will create a logger and a handler. When creating a handler, assign the class FileHandler and a file name as an attribute. Then set the handler to a logger:

Output

Warning.

If you would like to have more options when it comes to logging your apps, have a look at our Guide to logging with Loguru, which is the most popular third-party logging framework for Python.

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