Reference library

Streaming & messaging

Kafka-style pub/sub, event consumers, async pipelines, and message-driven workflows.

3 matches

At Most Once Fire-and-Forget Mock in Python

A Python mock that enforces send() is called at most once and records the arguments for verification.

class FireForgetMock:
    def __init__(self):
        self._calls = 0
        self._last_args = None
        self._last_kwargs = None

    def send(self, *args, **kwargs):
        if self._calls > 0:
            raise RuntimeError("send() called more than once")
        self._calls += 1
        self._last_args = args
…

16 0 Open

Streaming & messaging easy

How to Build a Message Stream Queue in Python

A beginner-friendly MessageStream class built on deque that sends messages one at a time, tracks unread counts, and records sent items.

queue deque streaming

Python

from collections import deque
import time


class MessageStream:
    def __init__(self, messages):
        self._queue = deque(messages)
        self._sent = []

    def send_next(self):
        if not self._queue:
            return None
        message = self._queue.popleft()
        self._sent.append(message)
     …

13 0 Open

Streaming & messaging medium

How to Implement an Outbox Table Poll Publisher in Python

This code simulates an outbox pattern with a class that polls for pending records and publishes them as JSON messages, removing only those that are due.

outbox polling messaging

Python

import time
import json
from dataclasses import dataclass, asdict
from datetime import datetime, timedelta

@dataclass
class OutboxRecord:
    id: int
    topic: str
    payload: dict
    created_at: datetime

class OutboxPollPublisher:
    def __init__(self, poll_interval_seconds=1):
        self.poll_interval = poll…

11 0 Open

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