How to List Failed Records in a Dead Letter Queue Mock in Python

import json
from datetime import datetime, timedelta
import random


class DeadLetterQueue:
    def __init__(self):
        self.failed_records = []

    def add_failed_record(self, record_id, payload, error_message):
        self.failed_records.append({
            "record_id": record_id,
            "payload": payload,
            "error_message": error_message,
            "failed_at": datetime.now().isoformat(),
            "attempts": random.randint(1, 5)
        })

    def list_failed_records(self):
        return self.failed_records

    def save_to_file(self, filename="dlq_failed_records.json"):
        with open(filename, "w") as f:
            json.dump(self.failed_records, f, indent=2)


if __name__ == "__main__":
    dlq = DeadLetterQueue()
    dlq.add_failed_record("rec-001", {"user": "Alice", "amount": 2500}, "Invalid amount: exceeds limit")
    dlq.add_failed_record("rec-002", {"user": "Bob", "email": "bob@example.com"}, "Email bounced: mailbox not found")
    dlq.add_failed_record("rec-003", {"user": "Carol", "order_id": 789}, "Duplicate order: already processed")

    print(json.dumps(dlq.list_failed_records(), indent=2))