IssueTracker

Requested Enhancement Description (What would you like to accomplish?)
Customers should be able to identify Discovery Engine API errors in Cloud Logging without requiring Data Access Audit logs. Additionally, when the API returns a 400 error due to a missing Data Store ID, the error level should be adjusted to a warning instead of an error for better clarity.

Detailed Functionality Description (How might it work? What needs to be changed?)

Enhance Cloud Logging for Discovery Engine API Errors:
Ensure that API errors, such as 400 and 499 errors, are logged by default in Cloud Logging without requiring Data Access Audit logs.
Provide visibility into API failures (e.g., method failures, error rates) within Cloud Logging to improve troubleshooting.
Include relevant metadata (e.g., project ID, region, affected API method) to assist with debugging.

Adjust Error Level for Missing Data Store ID:
Change the error level from error (400) to warning when a Data Store ID is missing.
This adjustment would prevent unnecessary escalations and make it clearer that this is a configuration issue rather than a system failure.

If Applicable, Reasons Why Alternative Solutions Are Not Sufficient

Enabling Data Access Audit Logs is Not Always Feasible:
Some customers have security and compliance policies that limit the use of Data Access Audit logs.
Audit logs can generate high costs, making them an impractical solution for monitoring API errors.

Current Error Messaging is Misleading:
A missing Data Store ID does not indicate an API failure but rather a user configuration issue.
Marking it as an error can cause unnecessary concern and confusion for customers.

Troubleshooting is Inefficient Without Proper Logging:
Without better logging, customers struggle to diagnose high error rates in Discovery Engine.
Lack of visibility into failed API requests increases the time required to resolve issues.

Other Information (Workarounds You Have Tried, Documentation Consulted, etc.)
Reviewed existing Cloud Logging documentation but found no way to log Discovery Engine API errors without Data Access Audit logs.
Consulted the debugging tree playbook, but no relevant troubleshooting steps were found.
Analyzed DiscoveryEngine and Dialogflow metrics, confirming high error rates but lacking sufficient error details in logs.