Nightly ETL: extract, transform, load как шаги пайплайна без Airflow

export async function handler(event) {
  const date = new Date().toISOString().slice(0, 10); // YYYY-MM-DD
  const records = await externalApi.fetchDailyReport(date);
  // Store to object storage — pipeline passes storage key to next step
  const key = `etl/raw/${date}.json`;
  await storage.putJson(key, records);
  return { key, count: records.length, date };
}

export async function handler(event) {
  const { key, date } = event.previousOutput ?? {};
  const raw = await storage.getJson(key);
  const transformed = raw.map((r) => ({
    id: r.external_id,
    date,
    revenue: parseFloat(r.revenue_usd),
    region: r.region?.toLowerCase(),
    updatedAt: new Date().toISOString(),
  }));
  const outKey = `etl/transformed/${date}.json`;
  await storage.putJson(outKey, transformed);
  return { outKey, count: transformed.length, date };
}