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OCW Studio — Architecture & Data Flows

Generated 2026-06-24 15:49 UTC · c4gen dev

OCW Studio is the static-site CMS for MIT OpenCourseWare. Course authors edit content in a React/TypeScript SPA backed by a Django/DRF API; content is versioned into per-site GitHub repos and uploaded media lands in S3. Publishing is delegated to Concourse CI pipelines that run Hugo (via ocw-hugo-themes / ocw-hugo-projects) to build online and offline (downloadable) static sites, sync them to preview/publish S3 buckets, and purge Fastly. Celery (Redis broker) drives content sync, Google Drive imports, video transcoding (AWS MediaConvert), YouTube upload, and 3Play transcription. On a live publish the pipeline fires an Open Catalog webhook so MIT Learn's ETL ingests the OCW site JSON from S3.

This is a C4 view of OCW Studio within the MIT Open Learning SOA, focused on how data is created and propagated — synchronous request paths and asynchronous (queued, scheduled, event-driven) flows alike. Use it for onboarding and as a holistic reference when realigning flows or hunting harmful cycles and fragile linkages.

How to read these diagrams

These are C4 model diagrams (C4-PlantUML). Read them top-down: System Context (the whole SOA) → Container (one system's runtime units) → Dynamic (a single data flow, step by step).

  • People are rounded boxes; systems and containers are rectangles; databases and queues have distinct shapes.
  • Each arrow is a data flow labelled with what moves.
  • Solid arrows are synchronous (request/response, caller blocks).
  • Amber dashed arrows are asynchronous (queued, scheduled, or event-driven — caller does not block).
  • Drag to pan, scroll to zoom. Boxes with a link drill into the next level.

Contents

  1. System Context — OCW Studio and the systems it exchanges data with.
  2. Containers — the runtime units inside OCW Studio.
  3. Data Flows — key interactions, step by step (sync & async).
  4. Dependencies & Cycles — graph-derived coupling, cycles, fragile links.

Keeping this current

These pages are generated from a structured model by architecture_maps/c4gen. The cross-service edges are extracted deterministically from the witan-code graph; node prose and scenarios are curated. See the generator README to regenerate after the system changes.