lognote 0.1.0

A Black Box Flight Recorder for Python applications.

lognote - Black Box Flight Recorder

lognote is a high-performance, threading-safe, zero-dependency "Black Box Flight Recorder" for Python applications. Designed specifically for production environments, it captures essential execution paths, performance metrics, and state-at-crash information without slowing down your host application.

Why lognote?

When a critical application crashes in production, having an exact playback of what happened is invaluable. However, tracing tools usually require external setups and carry a heavy performance hit or many dependencies. lognote runs entirely in the Python Standard Library, logging safely inside a lightweight memory buffer (limited to the last 100 events). It strictly monitors for performance bottlenecks and captures local frame variables right before a stack unrolls in severe crashes, meaning no more flying blind. Plus, lognote comes with an automatic Privacy Filter, ensuring passwords, tokens, and secret keys never leak into your logs.

Quick Start

Installation

Until published on PyPI, you can build it locally:

pip install .

Usage

from lognote import trace, monitor, report

# 1. Trace function calls and return values
@trace
def process_payment(user_id: str, secret_token: str, amount: float):
    return {"status": "success", "amount": amount}

# The Privacy Filter will automatically redact "secret_token"
process_payment("u123", "sk_live_123456789", 45.0)

# 2. Monitor code block performance
def heavy_computation():
    with monitor("Data Crunching Task"):
        # Simulated workload
        for i in range(1000000):
            pass

heavy_computation()

# 3. Capture crashes with exact locals
@trace
def faulty_function(my_password: str):
    x = 10
    y = 0
    # On crash, lognote captures x=10, y=0, and my_password="[REDACTED]"
    return x / y

try:
    faulty_function("my_super_secret_password")
except ZeroDivisionError:
    pass

# 4. Export the session locally
# Generates a JSON (or Markdown) report in the .lognote_logs directory
report_path = report(format="json")
print(f"Log saved to {report_path}")

Author

Vishal N

Feel free to reach out for collaborations or questions!