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Logging

Overview​

This logging system is designed to capture detailed logs of the application, including custom widget-related logs, warnings, errors, and exceptions. It uses Python's built-in logging module, integrated with Qt's QSettings for user preferences, and allows both file and console logging.

Key Features:​

  • Rotating File Handler: Logs are stored in a rotating file to avoid excessive log file sizes.
  • QSettings Integration: Logs can be conditionally shown based on a setting stored in QSettings.
  • Exception Handling: Unhandled exceptions are captured and logged with detailed traceback.

Logger Setup​

The logger is set up through the setupLogger() function. It configures:

  • A RotatingFileHandler for saving log entries to custom_widgets.log in a logs directory.
  • A console handler to print log messages to the console.
  • Log rotation: The log file will have a maximum size of 5 MB, with up to 3 backup logs.

Example​

logFilePath = os.path.join(os.getcwd(), "logs/custom_widgets.log")
logDirectory = os.path.dirname(logFilePath)
if logDirectory != "" and not os.path.exists(logDirectory):
    os.makedirs(logDirectory)

The log file path is defined as logs/custom_widgets.log, and the directory is created if it does not exist.

Logging Functions​

logInfo(message)​

Logs an informational message.

  • Level: INFO
  • Example: 
    logInfo("Application started")

logWarning(message)​

Logs a warning message.

  • Level: WARNING
  • Example: 
    logWarning("This is a warning")

logError(message)​

Logs an error message.

  • Level: ERROR
  • Example: 
    logError("An error occurred")

logException(exception, message="Exception")​

Logs an exception with detailed traceback.

  • Level: ERROR
  • Example: 
    try:
        1 / 0  # Deliberate exception
    except Exception as e:
        logException(e, "Division by zero error")

logCritical(message)​

Logs a critical message.

  • Level: CRITICAL
  • Example: 
    logCritical("Critical failure")

Exception Handling​

The system provides a global handler for unhandled exceptions by overriding sys.excepthook. When an unhandled exception occurs, it:

  1. Logs the exception with full traceback.
  2. Prints the detailed exception information to the console.
sys.excepthook = handle_unhandled_exception

Example​

If an unhandled exception occurs, the output will look like:

Unhandled exception occurred:
Traceback (most recent call last):
  File "example.py", line 10, in <module>
    1 / 0
ZeroDivisionError: division by zero

QSettings Integration​

get_show_custom_widgets_logs()​

This function retrieves the value of the showCustomWidgetsLogs setting stored in QSettings. If True, log messages are printed to the console.

  • Key: showCustomWidgetsLogs
  • Default Value: False

Example​

settings = QSettings("MyCompany", "MyApp")
value = settings.value("showCustomWidgetsLogs", False, type=bool)

set_show_custom_widgets_logs(value: bool)​

Sets the value of showCustomWidgetsLogs in QSettings.

  • Usage: 
    set_show_custom_widgets_logs(True)

You can setup your log value settings from your json styles file:

{
  "LiveCompileQss": true,
  "ShowLogs": true,
  "CheckForMissingicons": false,
  "QSettings": [
      {...}
  ]
}

Log File Location​

By default, the log file is stored in the logs/ directory relative to the current working directory:

  • Log file path: logs/custom_widgets.log
  • Backup log files: Up to 3 backup log files are kept with the rotating file handler, each with a maximum size of 5 MB.

Customization​

  • Log level: The log level is set to DEBUG by default. You can modify it in the setupLogger() function if needed.
  • Log format: The log format is set as %(asctime)s - %(levelname)s - %(message)s. You can customize the format as needed.

Example of Full Logging Workflow​

  1. Setup Logger: Initialize the logger at the beginning of your application.

    setupLogger()

  2. Log Messages: Use the logging functions throughout your application.

    logInfo("Application started")
    logWarning("This is a warning")
    logError("An error occurred")

  3. Handle Unhandled Exceptions: Configure the global exception handler to log unhandled exceptions.

    sys.excepthook = handle_unhandled_exception

  4. Configure Console Output: Use set_show_custom_widgets_logs(True) to display logs in the console.

This logging system provides a comprehensive, configurable, and scalable approach for tracking application activity, debugging issues, and handling exceptions in a clean and organized manner.