feat: implement per-user presentation compiler caching #1224
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rochala
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Nov 28, 2025
rochala
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Nov 28, 2025
| setMetalsStatus: MetalsStatus ~=> Callback, | ||
| dependencies: Set[ScalaDependency]) | ||
| dependencies: Set[ScalaDependency], | ||
| user: Option[User]) |
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I'd just always generate random uuid for client, what is more. I think that you can generate it when someone enters the website and dont store it in local storage
rochala
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Nov 28, 2025
| * @param userUuid - unique identifier for the user | ||
| * @param newConfiguration - the new configuration being requested | ||
| */ | ||
| private def findAndRemoveOldPCForUser(userUuid: String, newConfiguration: ScastieMetalsOptions): IO[Unit] = |
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I think that we don't need to do this ? Cache entries have 5 min expiration time. I'm also not sure how it is implemented underneath. Is key.cache blocking whole access to the cache ? Is it non-blocking ? If it is non blocking how it will behave when during the cleanup we send another new request from same user and different config. Concurrency is hard. If I were you I'd drop this method and just leave it up to the cache
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rochala
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metals-runner/src/main/scala/org/scastie/metals/ScastieMetals.scala
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Add UUID-based user identification to limit each user (anonymous or authenticated) to one presentation compiler at a time. Anonymous users get a persistent UUID stored in localStorage, while authenticated users use their GitHub login as identifier.
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Summary
Implements per-user presentation compiler (PC) caching. Each user (anonymous or authenticated) can now have at most one presentation compiler instance.
Key Changes
LocalStorage.getOrCreateClientUuid()to generate and persist UUIDs for anonymous users.Cache[IO, ScastieMetalsOptions, PC]toCache[IO, (String, ScastieMetalsOptions), PC]where String is the user UUID.