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Data pipelines & processing

ETL-style flows, batch transforms, validation, and moving data between formats.

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Generate a Mock CDC Changelog in Python

Simulate a CDC changelog with INSERT, UPDATE, and DELETE operations, timestamps, and record snapshots for testing data pipelines.

cdc changelog mock-data

Python

import json
from datetime import datetime, timedelta


def generate_mock_changelog(records, operations=("INSERT", "UPDATE", "DELETE")):
    """Simulate a CDC changelog from a list of record snapshots."""
    base_time = datetime(2025, 1, 1, 8, 0, 0)
    changelog = []
    for idx, record in enumerate(records):
       …

15 0 Open

Data pipelines & processing easy

How to Merge Incremental Snapshot Upsert Dict in Python

Merge a snapshot dict into a base dict, recursively updating nested dictionaries while preferring snapshot values on conflicts.

dict merge upsert

Python

def merge_upsert(base: dict, snapshot: dict) -> dict:
    """
    Merge a snapshot dict into a base dict, preferring snapshot values 
    on key conflicts (upsert semantics). Nested dicts are merged recursively.
    """
    result = dict(base)
    
    for key, value in snapshot.items():
        if key in result and i…

13 0 Open

Data pipelines & processing easy

How to create a dated snapshot path for a dataset in Python

Generate a versioned directory path combining a base directory, dataset name, and today's date, ready for creating snapshots in data pipelines.

date pathlib datasets

Python

import datetime
import os
from pathlib import Path


def snapshot_path(base_dir: str, dataset_name: str) -> Path:
    """Return a dated snapshot path for a dataset under a base directory."""
    today = datetime.date.today().isoformat()
    return Path(base_dir) / dataset_name / today


if __name__ == "__main__":
    …

15 0 Open

Data pipelines & processing easy

Rollback dataset to previous snapshot pointer in Python

A SnapshotManager class stores timestamped data snapshots and rolls back to the most recent snapshot at or before a target time.

snapshots rollback datetime

Python

from datetime import datetime, timedelta


class SnapshotManager:
    def __init__(self):
        self.snapshots = {}  # timestamp -> data
        self.current_pointer = None

    def create_snapshot(self, data):
        timestamp = datetime.now()
        self.snapshots[timestamp] = data
        self.current_pointer =…

13 0 Open

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