Maintainability and Legacy Code Questions

Covers strategies and principles for evolving codebases safely and keeping them easy to understand and change over time. Topics include design principles such as Single Responsibility, Open Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion, removing duplication, establishing appropriate abstraction boundaries, separation of concerns, identifying and remediating code smells, incremental refactoring approaches, regression risk mitigation via tests and feature toggles, backward compatibility and migration strategies, and prioritizing technical debt reduction. Interviewers assess the candidate ability to plan pragmatic refactors, minimize risk during change, and improve long term health of a codebase.

HardSystem Design

0 practiced

Design a minimally disruptive data migration strategy for a stateful service that must evolve its data model, supporting both old and new schema reads and writes during rolling upgrades. Cover versioned schemas, adapters, backfilling, consistency concerns and verification steps to ensure correctness with near-zero downtime.

EasyTechnical

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Explain the Single Responsibility Principle (SRP) and describe how you would apply it when refactoring a monolithic SRE automation script that currently handles alert parsing, remediation actions, log aggregation, and metrics emission. Identify concrete responsibilities you would separate, the benefits for reliability and testing, and one potential trade-off.

HardSystem Design

0 practiced

Design a strategy to refactor a data-access layer in a multi-region service so reads are region-local while maintaining a single logical API for clients. Discuss abstraction boundaries, consistency models, fallbacks, and how to roll out changes without breaking clients.

EasyTechnical

0 practiced

You find a 400-line Python function that parses alert payloads, decides remediation, executes external commands, and writes metrics all in one place. Identify at least six code smells present in such a function and propose an incremental refactor plan (first three steps) to make it maintainable while minimizing risk.

EasyTechnical

0 practiced

You manage a backlog of technical debt across multiple low-priority SRE services and have limited engineering time. Describe a framework to prioritize which technical debt to address first, including measurable criteria and how to present the trade-offs to product and platform stakeholders.

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