Reference library

Errors & debugging

Handle failures gracefully, raise helpful errors, and debug with confidence.

3 matches

How to Record Last N Errors with a Ring Buffer in Python

Use collections.deque with maxlen to keep only the most recent N error messages while discarding older entries automatically.

ring-buffer deque error-handling

Python

import collections

class ErrorRecorder:
    def __init__(self, size):
        self.buffer = collections.deque(maxlen=size)

    def record_error(self, message):
        self.buffer.append(message)

    def get_errors(self):
        return list(self.buffer)

if __name__ == "__main__":
    recorder = ErrorRecorder(3)
 …

13 0 Open

Errors & debugging easy

How to Use pdb.post_mortem in Python

Automatically enter the Python debugger at the exact point where an uncaught exception occurred, allowing interactive inspection of the crash site.

pdb debugging exceptions

Python

import pdb
import sys

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

def main():
    try:
        result = divide(10, 0)
        print(f"Result: {result}")
    except Exception:
        # Enter post-mortem debugging when an uncaught exception occurs
        pdb.post_mortem(sys.exc_info()[2])

if __name__ == "__main__":
    main…

13 0 Open

Errors & debugging medium

Implement circuit breaker open after failures demo in Python

A minimal CircuitBreaker class that calls a function and automatically 'opens' after a set number of consecutive failures, blocking further calls with a RuntimeError.

circuit-breaker resilience error-handling

Python

import time
from datetime import datetime


class CircuitBreaker:
    def __init__(self, threshold=3):
        self.threshold = threshold
        self.failure_count = 0
        self.is_open = False

    def call(self, func, *args, **kwargs):
        if self.is_open:
            raise RuntimeError("Circuit is OPEN")
  …

13 0 Open

Browse by section

Each section groups closely related Python snippets.