Automated data pipeline from Cloud Storage to BigQuery with ML forecasting for sales analytics

We successfully implemented a fully automated data pipeline that ingests CSV files from Cloud Storage, loads them into BigQuery, and runs ML forecasting models. Here’s our implementation story.

Our challenge was processing daily sales data uploads (500MB-2GB files) for predictive analytics. We needed serverless data ingestion to handle variable file sizes, BigQuery ML for demand forecasting, and automated pipeline monitoring to catch failures early.

The solution uses Cloud Functions triggered by GCS uploads, streaming inserts to BigQuery, and BQML ARIMA_PLUS models for time-series predictions. Cloud Monitoring tracks pipeline health with custom metrics.

# Cloud Function trigger example
def process_file(event, context):
    file_name = event['name']
    load_job = client.load_table_from_uri(f'gs://{bucket}/{file_name}', table_ref)
    load_job.result()  # Wait for completion

Pipeline runs daily with zero maintenance, processing takes 8-12 minutes end-to-end, and ML predictions update automatically. Happy to share architecture details and lessons learned.

Really interested in your BigQuery ML forecasting setup. Are you using ARIMA_PLUS for all predictions, or do you have multiple model types? How do you handle model retraining - is it scheduled or triggered by data quality metrics?

Also curious about forecast accuracy monitoring. Do you track MAPE or other metrics to detect when models need updating?

Our monitoring covers multiple layers. For Cloud Functions, we track execution duration (alert if >5min), invocation count, and error rates. BigQuery job monitoring includes load job failures, query execution times for ML model training, and slot utilization during peak hours.

Data freshness is critical for us - we use a custom metric that checks the max timestamp in our sales table. If no new data arrives within 26 hours (accounting for weekend delays), we get paged. We also monitor row counts per load to detect partial file uploads.

Cloud Monitoring dashboards show pipeline health at a glance: success rate, average processing time, current forecast accuracy, and cost per pipeline run. All metrics feed into uptime checks and alerting policies with PagerDuty integration for critical failures.

This is a great use case for serverless architecture! How are you handling schema validation before loading into BigQuery? With variable file sizes and daily uploads, I’m curious if you’re using any preprocessing steps or loading data directly.

Also, what’s your approach to handling malformed CSV records? Do Cloud Functions retry on failures, or do you have a separate error handling mechanism?