A large e-commerce company named ShopZone uses GCP to host its online store. Recently, the company noticed several errors reported by customers while…

The issue is with a custom "payment processing system," which is an application built by or for the company. Logs generated by such applications are categorized as "User-written logs" (also known as application logs) in Google Cloud's operations suite (formerly Stackdriver). These logs contain application-specific information, such as transaction details, error messages, and stack traces, which are essential for debugging application-level problems and identifying anomalies in business logic, as required in the scenario.

A. Component Logs: This is not a standard, top-level log category within Google Cloud Logging.
C. Platform logs: These are logs generated by the GCP services themselves (e.g., Compute Engine, Cloud Load Balancing), not the custom application code running on them.
D. Security logs: These logs, including Cloud Audit Logs, track administrative activities and resource access, which is not relevant for debugging an application logic error.

1. Google Cloud. (2023). Overview of Cloud Logging. Google Cloud Documentation. Retrieved from https://cloud.google.com/logging/docs/overview. Section: "Log types". This page explicitly defines "User-written logs" as "Logs that are written by user applications and services."

2. Google Cloud. (2023). About logs-based metrics. Google Cloud Documentation. Retrieved from https://cloud.google.com/logging/docs/logs-based-metrics/about. It distinguishes between system (platform) logs and application (user-written) logs for monitoring purposes.

3. Varia, J. (2017). Architecting for the Cloud: Best Practices. AWS Whitepaper. While an AWS source, the principle is universal and taught in cloud curricula. It distinguishes between infrastructure/service logs and application logs, stating the latter is crucial for debugging application behavior. GCP follows the same principle with its "User-written logs" category.