How to Send Messages to a Dead Letter Queue in Python

import json

class PoisonMessageQueue:
    def __init__(self, max_retries=3):
        self.dlq = []
        self.max_retries = max_retries
        self.processed_count = 0
        self.failed_count = 0

    def process_message(self, message_body):
        if "poison" in message_body:
            self.failed_count += 1
            retries = message_body.get("retries", 0)
            message_body["retries"] = retries + 1
            if retries >= self.max_retries - 1:
                self.dlq.append(message_body)
                return "sent_to_dlq"
            return "will_retry"
        self.processed_count += 1
        return "processed"

    def summary(self):
        return {
            "processed": self.processed_count,
            "failed": self.failed_count,
            "dlq_length": len(self.dlq)
        }

if __name__ == "__main__":
    queue_service = PoisonMessageQueue(max_retries=3)
    messages = [
        {"id": 1, "content": "normal message"},
        {"id": 2, "content": "poison message", "retries": 0},
        {"id": 3, "content": "poison message", "retries": 1},
        {"id": 4, "content": "poison message", "retries": 2}
    ]
    for msg in messages:
        result = queue_service.process_message(msg)
        print(f"Message {msg['id']}: {result}")
    print("Summary:", json.dumps(queue_service.summary()))