Reference library

Big data & Spark

PySpark jobs, partitioning, batch processing, and large-dataset transform patterns.

5 matches
Big data & Spark medium

Accumulators Global Counter Mock in Python

Shows an accumulator-style global counter with a mock patch to control its value in tests.

accumulator global state mock
Python
import unittest
from unittest.mock import patch

# Module-level global counter accumulator
counter = 0

def increment(by=1):
    """Increment the global counter in place (accumulator pattern)."""
    global counter
    counter += by
    return counter

def reset():
    """Reset the counter to zero."""
    global count…
14 0 Open
Big data & Spark medium

How to Mock a Catalyst Logical Plan in Python

Build a small Python class that mimics Spark Catalyst's logical plan tree for teaching or testing query optimizations.

apache-spark logical-plan catalyst
Python
from typing import Any, Dict, List, Optional


class CatalystLogicalPlan:
    """A minimal mock of Catalyst's logical plan for teaching purposes."""
    
    def __init__(self, node_type: str, **kwargs: Any) -> None:
        self.node_type = node_type
        self.attributes: Dict[str, Any] = kwargs
        self.child…
13 0 Open
Big data & Spark medium

How to Mock a Compute-Collect Action Trigger in Python

Mock a compute-collect action trigger using Python's unittest.mock to simulate Spark-style job execution and assert trigger behavior.

testing mock spark
Python
Here's a Python code sample for the problem title "Action trigger compute collect mock":
14 0 Open
Big data & Spark medium

How to Mock and Test a Rate-Limited Source Stream in Python

Build a class that rate-limits emitted items using a sliding window and test it with a simulated stream in Python.

rate-limiting mock-testing streaming
Python
import time
from collections import deque


class RateLimitedSource:
    def __init__(self, max_rate, window=1.0):
        self.max_rate = max_rate
        self.window = window
        self._timestamps = deque()

    def emit(self, item):
        now = time.monotonic()
        while self._timestamps and self._timestam…
16 0 Open
Big data & Spark medium

How to use foreachBatch with a mock sink in PySpark

Demonstrates using Spark Structured Streaming's foreachBatch sink to capture and verify streaming batches by writing them into a custom mock sink object.

pyspark structured-streaming foreachbatch
Python
from pyspark.sql import SparkSession
from pyspark.sql.functions import col, lit

class MockSink:
    def __init__(self):
        self.batches = []
    
    def write_batch(self, batch_df, batch_id):
        # Collect batch data as list of dicts for verification
        records = batch_df.collect()
        self.batches…
14 0 Open

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Big data & Spark — Python code examples

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This page collects big data & spark snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.

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