Enhancing Python Error Messages with PrettyError

Programming often spends a large portion of time reading and fixing error messages, which can be verbose and hard to parse. The PrettyError library addresses these pain points by providing colorful, concise, and configurable error output.

1. Installation and Quick Start

Install PrettyError via pip: pip install pretty_errors Import the library and run a simple function to see the default error output:

import pretty_errors

def divide(a, b):
    return a / b

divide(1, 0)

After importing, the error is displayed with colored highlights, showing the exception type, file, and line.

2. Main Features

2.1 Configurable Colors

You can customize colors using the configure() function:

import pretty_errors

pretty_errors.configure(
    line_color=pretty_errors.BRIGHT_RED,
    exception_color=pretty_errors.BRIGHT_MAGENTA,
    exception_arg_color=pretty_errors.CYAN,
    exception_file_color=pretty_errors.RED_BACKGROUND + pretty_errors.BRIGHT_WHITE
)

open("non_existent_file.txt")

2.2 Adding Timestamps

Enable timestamps in error output:

import pretty_errors

pretty_errors.configure(display_timestamp=1)
open("non_existent_file.txt")

Or provide a custom timestamp function:

import pretty_errors, datetime

pretty_errors.configure(
    display_timestamp=1,
    timestamp_function=lambda: datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S')
)
open("non_existent_file.txt")

2.3 Showing More Code Context

Use lines_before and lines_after to display surrounding code lines:

import pretty_errors

pretty_errors.configure(lines_before=2, lines_after=1)

# The output should show these comments (lines before)

def calculate(x):
    return 1 / x

# The output should show this comment (lines after)

calculate(0)

2.4 Controlling Stack Depth

Limit the displayed stack trace with stack_depth:

import pretty_errors

pretty_errors.configure(stack_depth=1)

def calculate(x):
    return 1 / x

def wrapper():
    calculate(0)

wrapper()

2.5 Displaying Local Variables

Show variable values in the traceback by setting display_locals=1:

import pretty_errors

pretty_errors.configure(display_locals=1)

def calculate_divide(x, y):
    return x / y

calculate_divide(1, 0)

2.6 Environment‑Based Configuration

Adjust PrettyError settings based on an environment variable:

import pretty_errors, os

if os.getenv('ENV') == 'development':
    pretty_errors.configure(stack_depth=0, display_locals=1)
else:
    pretty_errors.configure(stack_depth=1, display_locals=0)

def calculate(x):
    return 1 / x

def wrapper():
    calculate(0)

wrapper()

The article concludes that PrettyError simplifies Python error messages through color coding, timestamps, variable display, and flexible configuration, helping developers debug more efficiently.