Pipeline 실행 예약과 로깅

From Notebook to Script

# pipeline.py
import argparse
import logging
import pandas as pd

def main(config_path):
    logging.info(f'Starting pipeline with config: {config_path}')
    # ... run ETL steps ...
    logging.info('Pipeline complete.')

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--config', default='config.json')
    args = parser.parse_args()
    main(args.config)

Configuring Python Logging

import logging
from datetime import date

log_file = f'pipeline_{date.today()}.log'

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s %(levelname)s %(message)s',
    handlers=[
        logging.FileHandler(log_file),
        logging.StreamHandler()
    ]
)

logging.info('Logger configured.')

Logging Pipeline Start and End

import time
import logging

def run_pipeline(config):
    start = time.time()
    logging.info(f'Pipeline START | env={config.get("env", "dev")} | input={config["input_path"]}')

    try:
        df = extract(config)
        df_clean = transform(df, config)
        load(df_clean, config)
        elapsed = time.time() - start
        logging.info(f'Pipeline SUCCESS | rows={len(df_clean)} | elapsed={elapsed:.1f}s')
    except Exception as e:
        logging.error(f'Pipeline FAILED | error={e}', exc_info=True)
        raise

Logging Row Counts Per Step

def log_step(df, step_name):
    logging.info(f'{step_name}: {len(df):,} rows')
    return df

import pandas as pd

df = (pd.read_csv('orders.csv')
    .pipe(log_step, 'extract')
    .dropna(subset=['revenue'])
    .pipe(log_step, 'drop_nulls')
    .query('quantity > 0')
    .pipe(log_step, 'filter_qty')
)
print('Step logging complete.')

Scheduling with cron on Linux/Mac

# crontab entry — edit with: crontab -e
# Run pipeline.py at 06:00 every day
# 0 6 * * * /opt/homebrew/bin/python /Users/analyst/pipeline.py --config /Users/analyst/config.json >> /Users/analyst/cron.log 2>&1

# Common cron patterns:
# 0 6 * * *      — daily at 06:00
# 0 */4 * * *    — every 4 hours
# 0 9 * * 1      — every Monday at 09:00
print('Cron schedule format: minute hour day month weekday')

Scheduling with Python schedule Library

# pip install schedule
# import schedule, time

# def job():
#     logging.info('Scheduled run starting...')
#     run_pipeline(CONFIG)

# schedule.every().day.at('06:00').do(job)
# schedule.every(4).hours.do(job)

# while True:
#     schedule.run_pending()
#     time.sleep(60)

print('schedule library: use for in-process Python scheduling')

Error Handling and Exit Codes

import sys

def main():
    try:
        run_pipeline(CONFIG)
        sys.exit(0)  # success
    except AssertionError as e:
        logging.error(f'Data validation failed: {e}')
        sys.exit(2)  # data error
    except Exception as e:
        logging.error(f'Unexpected error: {e}', exc_info=True)
        sys.exit(1)  # general failure

print('Exit code 0=success, 1=error, 2=data failure')

Writing a Pipeline Run Summary File

import json
from datetime import datetime

def write_run_summary(config, input_rows, output_rows, elapsed):
    summary = {
        'run_at': datetime.now().isoformat(),
        'input_path': config['input_path'],
        'input_rows': input_rows,
        'output_rows': output_rows,
        'rows_dropped': input_rows - output_rows,
        'elapsed_seconds': round(elapsed, 2),
        'status': 'success'
    }
    with open('last_run_summary.json', 'w') as f:
        json.dump(summary, f, indent=2)
    print('Run summary written.')

Idempotent Scheduling: Avoiding Double Runs

from datetime import date

def load_idempotent(df, config):
    # Date-stamped output: each run overwrites its own day's file
    output_path = f"output_{date.today().strftime('%Y%m%d')}.parquet"
    df.to_parquet(output_path, index=False)
    logging.info(f'Loaded {len(df)} rows to {output_path}')

Alerting on Pipeline Failure

import smtplib

def send_failure_alert(error_msg):
    # Example: send plain-text email via SMTP
    # server = smtplib.SMTP('smtp.example.com', 587)
    # server.sendmail('pipeline@company.com',
    #                 'analyst@company.com',
    #                 f'Subject: Pipeline Failed\n\n{error_msg}')
    # server.quit()
    print(f'[ALERT] Would send failure notification: {error_msg}')

# In main():
# except Exception as e:
#     send_failure_alert(str(e))
#     sys.exit(1)
print('Alert integration pattern shown above.')

Complete Scheduled Pipeline Script

# Full script skeleton:
# 1. parse --config argument
# 2. configure logging to file + console
# 3. load JSON config
# 4. validate config
# 5. run extract() -> transform() -> load()
# 6. write run summary JSON
# 7. sys.exit(0) on success, sys.exit(1) on failure

print('Production pipeline script structure complete.')
print('Schedule with: crontab -e  or  python scheduler.py')

Quick Check

Lesson Recap