A Function App is typically used for serverless, small-scale, and responsive tasks, ensuring the overall pipeline remains reactive and efficient.
Triggering the Pipeline: The Function App can be triggered by new events—for example, a new client document (PDF, image) being uploaded to Azure Data Lake Storage Gen2. Its primary function is to kick off the main Azure Data Factory (ADF) pipeline that moves data from the Bronze to the Silver layer.
Small-Scale Data Transformation: Instead of using a full Spark cluster for tiny tasks, the Function App can handle micro-transformations. This might include reading metadata from a raw file in the Bronze Layer, validating a simple checksum, or sending a quick notification to a Relationship Manager if a critical file is missing.
Security and Governance Checks: A Function App could implement access control or governance checks on the Gold Layer consumption endpoints. For example, it could verify a user’s role before granting access to a specific aggregated report, or securely pull an encryption key from a service like Azure Key Vault and pass it to the data consumer.
In essence, the Function App manages the orchestration and immediate responses for events, leaving the heavy lifting of data cleaning and transformation to the more powerful Spark SQL engines.
