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Python Code Samples

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4 matches
Streaming & messaging medium

How to Mock Offset Commit Auto vs Manual in Python

Demonstrates a Kafka-style offset commit function with auto/manual modes and tests it using unittest.mock.patch.

unittest mocking kafka
Python
from unittest.mock import Mock, patch

def commit_offsets(topic_partition_offsets, auto_commit=False):
    """Manually commit offsets or simulate auto-commit."""
    if auto_commit:
        print(f"Auto-committing offsets: {topic_partition_offsets}")
        return {"status": "auto_committed"}
    
    print(f"Manuall…
15 0 Open
Streaming & messaging medium

Kafka Consumer Poll Loop Mock in Python

Simulate a Kafka consumer poll loop with a mock class, process messages in batches, and commit offsets to understand streaming consumption patterns.

kafka streaming mock
Python
import time

class MockKafkaConsumer:
    def __init__(self, topic, messages):
        self.topic = topic
        self.messages = list(messages)
        self.position = 0

    def poll(self, timeout_ms=100):
        if self.position >= len(self.messages):
            time.sleep(timeout_ms / 1000)
            return []…
13 0 Open
Database scaling & optimization medium

How to Implement Keyset Pagination in Python (Seek Method)

Implement keyset (seek) pagination in Python with a mock paginator that efficiently fetches pages based on the last row rather than OFFSET.

pagination keyset seek-method
Python
from dataclasses import dataclass
from typing import List, Optional


@dataclass
class Row:
    id: int
    name: str

    def __lt__(self, other: "Row") -> bool:
        return (self.id, self.name) < (other.id, other.name)


class MockKeysetPaginator:
    """Pagination using keyset (seek) method instead of OFFSET."""…
14 0 Open
Database scaling & optimization medium

Offset vs Keyset Pagination in Python

Demonstrate offset-based pagination and keyset (cursor) pagination with a simple in-memory dataset, showing how each returns pages of records.

pagination keyset offset
Python
"""Demonstrate pagination using offset vs keyset (cursor) approach."""

ITEMS = [
    {"id": 1, "name": "Alice"},
    {"id": 2, "name": "Bob"},
    {"id": 3, "name": "Carol"},
    {"id": 4, "name": "David"},
    {"id": 5, "name": "Eve"},
]

def offset_paginate(items, page, page_size):
    """Return a page using offset…
14 0 Open

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