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data_pipeline_for_YNAB/pipeline/duckdb_layer.py
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2026-07-26 14:39:07 +01:00

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9.7 KiB
Python

"""DuckDB-based silver and gold layer for the YNAB data pipeline."""
import os
from datetime import date, timedelta
import duckdb
class DuckDBLayer:
"""Orchestrates silver (external base) and gold (views + materialized) layers via DuckDB."""
def __init__(self, base_path: str, warehouse_path: str, logger):
self.base_path = base_path
self.warehouse_path = warehouse_path
self.logger = logger
self.db = None
os.makedirs(self.warehouse_path, exist_ok=True)
self._init()
def _silver_parquet_expr(self, entity: str) -> str:
return f"read_parquet('{self.base_path}/{entity}.parquet')"
def _init(self):
self.db = duckdb.connect('/mnt/bulk/data/ynab_data.duckdb')
self._setup_schemas()
self._create_silver_external_tables()
self._drop_gold()
self._create_gold_views()
self._create_gold_dates()
self._create_gold_facts()
def _setup_schemas(self):
self.db.execute("CREATE SCHEMA IF NOT EXISTS silver")
self.db.execute("CREATE SCHEMA IF NOT EXISTS gold")
def _create_silver_external_tables(self):
entities = ['accounts', 'categories', 'payees', 'transactions', 'scheduled_transactions']
for entity in entities:
sql = f"CREATE TABLE IF NOT EXISTS silver.{entity} AS SELECT * FROM {self._silver_parquet_expr(entity)}"
try:
self.db.execute(sql)
self.logger.info(f"Created silver.{entity}")
except Exception as e:
self.logger.error(f"Failed to create silver.{entity}: {e}")
self.logger.info("Silver layer initialized")
def _drop_gold(self):
for name in ['accounts', 'categories', 'payees']:
self.db.execute(f"DROP VIEW IF EXISTS gold.{name}")
self.db.execute("DROP TABLE IF EXISTS gold.dates")
self.db.execute("DROP TABLE IF EXISTS gold.transactions")
self.db.execute("DROP TABLE IF EXISTS gold.scheduled_transactions")
# ── gold views (dimensions) ─────
def _create_gold_accounts_view(self):
self.logger.info("Transforming and creating gold.accounts view")
sql = """
SELECT
id AS account_id,
name AS account_name,
"type" AS account_type,
on_budget,
closed,
COALESCE(CAST(note AS VARCHAR), 'none') AS note,
balance / 1000.0 AS balance,
cleared_balance / 1000.0 AS cleared_balance,
uncleared_balance / 1000.0 AS uncleared_balance,
deleted
FROM silver.accounts
"""
try:
self.db.execute(f"CREATE VIEW gold.accounts AS {sql}")
self.logger.info("Created gold.accounts view")
except Exception as e:
self.logger.error(f"Failed to create gold.accounts view: {e}")
def _create_gold_categories_view(self):
self.logger.info("Transforming and creating gold.categories view")
sql = """
SELECT
id AS category_id,
name AS category_name,
category_group_name,
hidden,
COALESCE(CAST(note AS VARCHAR), 'none') AS note,
budgeted / 1000.0 AS budgeted,
activity / 1000.0 AS activity,
balance / 1000.0 AS balance,
deleted
FROM silver.categories
"""
try:
self.db.execute(f"CREATE VIEW gold.categories AS {sql}")
self.logger.info("Created gold.categories view")
except Exception as e:
self.logger.error(f"Failed to create gold.categories view: {e}")
def _create_gold_payees_view(self):
self.logger.info("Transforming and creating gold.payees view")
sql = """
SELECT
id AS payee_id,
name AS payee_name,
deleted
FROM silver.payees
"""
try:
self.db.execute(f"CREATE VIEW gold.payees AS {sql}")
self.logger.info("Created gold.payees view")
except Exception as e:
self.logger.error(f"Failed to create gold.payees view: {e}")
def _create_gold_views(self):
self._create_gold_accounts_view()
self._create_gold_categories_view()
self._create_gold_payees_view()
# ── gold dates (materialized as Parquet, loaded into DuckDB) ─────
def _create_gold_dates(self):
dates_path = os.path.join(self.warehouse_path, 'dates.parquet')
self.logger.info("Creating gold.dates dimension")
try:
start = date(2020, 1, 1)
end = date(2030, 12, 31)
days = (end - start).days + 1
rows = []
for i in range(days):
d = start + timedelta(days=i)
month_z = str(d.month).zfill(2)
day_z = str(d.day).zfill(2)
rows.append({
'date_id': f"{d.year}{month_z}{day_z}",
'date': d,
'year': int(d.year),
'month': int(d.month),
'day': int(d.day),
'weekday': int(d.isoweekday()),
'is_weekday': 1 if d.isoweekday() < 6 else 0,
})
import pyarrow as pa
import pyarrow.parquet as pq
dates_df = pa.Table.from_pylist(rows)
dates_df = dates_df.cast(pa.schema([
('date_id', pa.string()),
('date', pa.date32()),
('year', pa.int32()),
('month', pa.int8()),
('day', pa.int8()),
('weekday', pa.int8()),
('is_weekday', pa.int8()),
]))
pq.write_table(dates_df, dates_path)
self.db.execute(f"CREATE TABLE gold.dates AS SELECT * FROM read_parquet('{dates_path}')")
self.logger.info(f"Created gold.dates and persisted to {dates_path}")
except Exception as e:
self.logger.error(f"Failed to create gold.dates: {e}")
# ── gold facts (materialized as Parquet) ─────
def _create_gold_transactions_fact(self):
transactions_path = os.path.join(self.warehouse_path, 'transactions.parquet')
self.logger.info("Transforming and persisting gold.transactions fact")
sql = f"""
COPY (
SELECT
memo,
cleared,
approved,
COALESCE(CAST(flag_color AS VARCHAR), 'none') AS flag_color,
account_id,
payee_id,
category_id,
transfer_account_id,
id AS transaction_id,
CAST(YEAR(CAST(date AS DATE)) AS VARCHAR)
|| LPAD(CAST(MONTH(CAST(date AS DATE)) AS VARCHAR), 2, '0')
|| LPAD(CAST(DAY(CAST(date AS DATE)) AS VARCHAR), 2, '0') AS transaction_date,
amount / 1000.0 AS transaction_amount,
deleted
FROM silver.transactions
) TO '{transactions_path}' (FORMAT PARQUET)
"""
try:
self.db.execute(sql)
self.logger.info(f"Persisted transactions.fact to {transactions_path}")
except Exception as e:
self.logger.error(f"Failed to create transactions.fact: {e}")
def _create_gold_scheduled_transactions_fact(self):
st_path = os.path.join(self.warehouse_path, 'scheduled_transactions.parquet')
self.logger.info("Transforming and persisting gold.scheduled_transactions fact")
sql = f"""
COPY (
SELECT
CAST(date_first AS DATE) AS date_first,
CAST(date_next AS DATE) AS date_next,
frequency,
COALESCE(memo, 'none') AS memo,
COALESCE(CAST(flag_color AS VARCHAR), 'none') AS flag_color,
account_id,
payee_id,
category_id,
transfer_account_id,
id AS scheduled_transaction_id,
amount / 1000.0 AS scheduled_transaction_amount
FROM silver.scheduled_transactions
) TO '{st_path}' (FORMAT PARQUET)
"""
try:
self.db.execute(sql)
self.logger.info(f"Persisted scheduled_transactions.fact to {st_path}")
except Exception as e:
self.logger.error(f"Failed to create scheduled_transactions.fact: {e}")
def _create_gold_facts(self):
self._create_gold_transactions_fact()
self._create_gold_scheduled_transactions_fact()
# Create DuckDB tables from the persistent Parquet files so they're queryable
self._register_facts()
def _register_facts(self):
"""Register the fact Parquet files as DuckDB tables."""
try:
self.db.execute(f"CREATE TABLE gold.transactions AS SELECT * FROM read_parquet('{os.path.join(self.warehouse_path, 'transactions.parquet')}')")
self.db.execute(f"CREATE TABLE gold.scheduled_transactions AS SELECT * FROM read_parquet('{os.path.join(self.warehouse_path, 'scheduled_transactions.parquet')}')")
self.logger.info("Registered fact tables in DuckDB")
except Exception as e:
self.logger.error(f"Failed to register fact tables: {e}")
def close(self):
if self.db:
self.db.close()
def get_duckdb_layer(base_path: str, warehouse_path: str, logger) -> DuckDBLayer:
"""Factory function to create a DuckDB layer and perform all transformations."""
return DuckDBLayer(base_path, warehouse_path, logger)