🧰 ThrowPy

ThrowPy is a lightweight Python library that provides a simple and elegant way to make any function or class method "throwable", similar to Java-style exception handling.

It offers an easy-to-use decorator — @ThrowableExcept — that automatically catches exceptions, prints meaningful error messages, and optionally logs them to a file.

Features

• 🔹 Simple decorator-based usage
• 🔹 Automatic exception catching with file and line context
• 🔹 Optional file logging (logErr=True)
• 🔹 Works with both functions and class methods
• 🔹 Minimal dependencies (pure Python)
• 🔹 Python 3.8+ compatible

1. Installation

You can install ThrowPy directly from PyPI:

pip install throwpy

2. Import and Basic Usage

The decorator can be applied to functions or methods.

from throwpy import ThrowableExcept

When a decorated function raises an exception, the decorator intercepts it, generates a structured error message, and: prints it to the console (stdout) if logErr=True, writes it to a specified log file The decorator returns None when an exception occurs (i.e., it does not re-raise the error).

3. Decorator Parameters

logErr (bool)

Purpose: Enables or disables writing the error message to a file. Default: True (if not specified, logging to file is enabled).

If logErr=False, the decorator will not attempt to write to a file, but the error message will still be printed to the console.

logfile (string)

Purpose: Specifies the path/name of the log file where error messages are appended. Default: "logErr.log" (typically created in the current working directory).

If logErr=True but the logfile cannot be written to (e.g., due to missing permissions), an error will be caught and a message such as [LOGGING ERROR] Unable to write log: … will be printed to the console.

4. Usage Examples

4.1 Simple Function with Default File Logging

from throwpy import ThrowableExcept

@ThrowableExcept()  # equivalent to logErr=True, logfile="logErr.log"
def divide(a, b):
    return a / b

divide(10, 0)

Behavior: The ZeroDivisionError is intercepted. A message similar to the following is generated:

[2025-11-04 18:00:00.123456][ERROR] script.py:12 <no class>.divide() -> division by zero

The message is printed to the console and appended to the file logErr.log (created if it doesn’t exist).

4.2 Disabling File Logging

@ThrowableExcept(logErr=False)
def get_item(lst, idx):
    return lst[idx]

get_item([], 5)

Behavior: The IndexError is intercepted. The message is printed to the console, but not written to any file.

4.3 Using a Custom Log File

@ThrowableExcept(logErr=True, logfile="errors/my_errors.log")
def risky_operation(x):
    return 10 / x

risky_operation(0)

Behavior: If the errors/ directory exists and my_errors.log is writable, the log will be written there. If writing fails (e.g., directory doesn’t exist or permissions are missing), a message like:

[LOGGING ERROR] Unable to write log: <internal error>

will be printed.

4.4 Usage in Classes (Methods)

class Example:
    @ThrowableExcept()
    def risky(self, x):
        return 100 / x

ex = Example()
ex.risky(0)

Behavior: The generated message will include the class name:

[2025-11-04 18:05:34.567890][ERROR] myfile.py:45 Example.risky() -> division by zero