Context manager for a scoped transaction log

Python data engineering interview problem. Difficulty: advanced. Pattern: OOP. About 20 minutes. Part of the Pro drill bank.

A job writes a transaction log that must close even if the body fails. A context manager is the Python way to guarantee setup/teardown.

Implement a context manager that records a scoped transaction log as the tests specify.

Requirements

• Enter writes a start marker.
• Exit writes an end marker even if an op fails, unless tests want a different policy.

Constraints

• ops: operations to run inside the scope.
• Exceptions inside should follow the tests (swallow vs propagate).

Examples

Input: run_transaction(['ok', 'ok']) Output: {'status': 'committed', 'ran': 2} This input follows the stated rules and produces this output.

Topics: lakebench, python, OOP.

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