[PECOBLR-1172] Add Configuration and Protocol Selection for SEA Phase 1

[jayantsing-db]

Summary

This PR implements Task 1 of SEA (Statement Execution API) Phase 1: Add Configuration and Protocol Selection support for the Databricks SQL Go driver.

This is a foundational change that enables protocol selection between Thrift (existing) and REST (new Statement Execution API) protocols.

Changes

Configuration Fields Added

UserConfig:

• ExecutionProtocol (string): Selects between "thrift" (default) or "rest"
• WarehouseID (string): Required when using REST protocol

Config:

• MaxPollInterval (time.Duration): Maximum polling interval for exponential backoff (default: 60s)
• PollBackoffMultiplier (float64): Multiplier for exponential backoff (default: 2.0)

DSN Parsing

Implemented parsing for the following query parameters:

• protocol or executionProtocol: Sets the execution protocol
• warehouse_id or warehouseId: Sets the warehouse ID (supports both naming conventions)

Example DSN: token:[email protected]:443/sql/1.0/endpoints/abc123?protocol=rest&warehouse_id=warehouse123

Validation

Added validation to ensure warehouse_id is provided when using protocol=rest. Returns a clear error message if missing.

Default Values

• ExecutionProtocol: "thrift" (maintains backward compatibility)
• MaxPollInterval: 60 seconds
• PollBackoffMultiplier: 2.0
• Existing PollInterval: 1 second (unchanged)

Testing

• Added 7 new test cases covering:
  • Protocol parameter parsing (thrift/rest)
  • Warehouse ID parsing (snake_case and camelCase)
  • Validation error when REST protocol missing warehouse_id
  • Alternative parameter names (executionProtocol)
  • Backward compatibility (default protocol is thrift)
• Updated all existing test cases to include new default fields
• Added tests for default values and DeepCopy functionality

All tests pass successfully.

Design Reference

Implementation follows the design document: statement-execution-api-design-go.md

Backward Compatibility

✅ All changes are backward compatible:

• Existing code continues to work without changes
• Default protocol is "thrift"
• New fields are optional (except warehouse_id when using REST)

Next Steps

This PR enables the foundation for subsequent SEA Phase 1 tasks:

• Task 2: Implement REST client infrastructure
• Task 3: Add result fetching capabilities

Test Plan

• [x] All existing unit tests pass
• [x] New unit tests added and passing
• [x] Build succeeds without errors
• [x] Pre-commit hooks pass

Related

• JIRA: PECOBLR-1172
• Design Doc: statement-execution-api-design-go.md

[jayantsing-db]

Why is DCO check failing post sign-off?