Moriel Schottlender: The Challenges of Modernizing MediaWiki's Monolith

Welcome to another engaging episode of the Maintainable Software Podcast! In this episode, Robby sits down with Moriel Schottlender, Principal Software Engineer at the Wikimedia Foundation, to explore the complex journey of modernizing MediaWiki, the software behind Wikipedia. Moriel shares her insights on what it takes to keep an enormous monolithic codebase maintainable while supporting an ever-growing and diverse set of global users. She highlights the importance of modularization, ownership, and the delicate balance between flexibility and stability in open-source software.Key Takeaways [00:00:51] Characteristics of Well-Maintained Software: Moriel discusses the three crucial characteristics of well-maintained software: ownership, modularization, and documentation. [00:01:09] Ownership and Rules for Contribution: Ownership goes beyond just fixing bugs—it involves understanding the architectural purpose and maintaining consistency even as teams change. [00:03:35] Product Vision's Role in Maintainability: Why a clear product vision is essential for maintaining software, even in the face of organic growth. [00:07:14] Balancing Experimentation and Long-Term Planning: Moriel shares insights into how Wikimedia balances rapid experimentation with careful, long-term architectural planning. [00:07:32] The Evolution of MediaWiki: MediaWiki's growth from a small project to the backbone of Wikipedia, now supporting over 900 wikis, and the challenges that come with scaling. [00:14:18] Modernizing a 23-Year-Old Monolith: Robby and Moriel dive into the challenges of modernizing MediaWiki’s architecture, including the difficulties of updating a monolithic structure. [00:17:15]Wikitext vs. Markdown: Moriel explains why MediaWiki uses its own Wikitext language instead of Markdown and the unique challenges it presents. [00:22:25] Architectural Flexibility for the Future: The importance of having a flexible architecture that can adapt to the evolving needs of users and technologies. [00:26:04] Technical Debt and Modularization: How Wikimedia approaches technical debt in MediaWiki and prioritizes architectural interventions to improve modularity and maintainability. [00:39:00] Community Contributions to MediaWiki: Strategies for increasing developer contributions and how Wikimedia empowers volunteers while maintaining software quality. [00:41:59] Advice for Aspiring Open Source Contributors: Moriel shares encouraging words for anyone looking to contribute to open-source projects, emphasizing that everyone can make a meaningful impact. [00:35:44] The Role of Documentation: Moriel discusses Wikimedia's efforts to improve documentation and ensure it's useful for both developers and end-users, leveraging the strengths of wiki-based contributions. [00:30:29] Celebrating Small Wins: Moriel talks about how Wikimedia celebrates small victories to keep team morale high in the face of big challenges.Resources MentionedMoriel's WebsiteMoriel on MastodonMediaWiki DocumentationBook Recommendation:Year Zero by Rob ReidConnect with MorielMoriel on LinkedInInstagramTwitterGitHubMastodonThanks to Our Sponsor! Turn hours of debugging into just minutes! AppSignal is a performance monitoring and error-tracking tool designed for Ruby, Elixir, Python, Node.js, Javascript, and other frameworks. It offers six powerful features with one simple interface, providing developers with real-time insights into the performance and health of web applications. Keep your coding cool and error-free, one line at a time!  Use the code maintainable to get a 10% discount for your first year. Check them out! Subscribe to Maintainable on:Apple PodcastsSpotify Or search "Maintainable" wherever you stream your podcasts. Keep up to date with the Maintainable Podcast by joining the newsletter.