How to Convert Logging Level Strings in JSON to Actual Logger Levels in Python

Learn how to avoid errors when reading logging levels from JSON in Python. Discover how to map string log levels to actual logging values to streamline your logging setup.
---

Visit these links for original content and any more details, such as alternate solutions, comments, revision history etc. For example, the original title of the Question was: Reading a logging level from JSON but not interpreting it as a string

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Reading a Logging Level from JSON without Interpreting it as a String

When working with JSON configurations in Python, you may encounter a common issue: reading logging levels that appear as strings instead of the actual logging constants needed for your logger. For instance, you might have a JSON file that specifies a logging level like this:

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

While trying to set up your logger using this value, you might face a frustrating error message such as:

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

This problem arises because the logger expects a logging level to be an actual constant (like logging.INFO), not a string representation ('logging.INFO'). In this guide, we will discuss a practical solution to this issue, ensuring smooth logging configuration without the hassle of errors.

The Problem Explained

When you load the JSON configuration file in Python, the logging level is read as a string. Consequently, when you attempt to set the logger’s level with that string, the logger fails to recognize it, leading to a ValueError.

Here's a snippet of how you might currently be managing your logger setup:

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

Clearly, the solution requires us to convert this string into the appropriate logging level constant that the logger can understand.

The Solution: Using a Dictionary to Map Strings to Logging Levels

To resolve this issue, we will create a dictionary that maps the string representations of logging levels to the actual logging constants provided by the logging module. This way, we can easily translate the string value from the JSON into the appropriate constant.

Step-by-Step Approach

Define a mapping dictionary: Create a dictionary that maps the string values to their corresponding logging levels.

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

Use the mapping when setting the log level: Modify your logger setup to utilize this mapping dictionary.

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

Additional Note

Another approach, although slightly different from this mapping method, is to drop the prefix logging. in your JSON configuration. Logging supports using just the string representation of the log levels, like so:

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

In this case, your logger setup would be simplified:

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

However, if you prefer retaining the logging. prefix for clarity, the mapping dictionary method is the best fit.

Conclusion

By implementing a dictionary to map the string representations of logging levels to their actual constants, you can simplify your logging setup and eliminate errors related to unrecognized levels. Now, you can maintain a clean and organized logging configuration in your JSON files without sacrificing functionality.

With this guide, you should be well-equipped to handle logging levels effectively in your Python applications!