resource-management_skill

Overview

This skill explains how to manage resources safely using Effect so cleanup is guaranteed even on errors or interruptions. It covers scopes, acquire/release patterns, finalizers, scoped effects, and common resource examples like files, DB connections, and locks. The focus is practical: how to acquire, use, and reliably release resources in real programs.

How this skill works

Effect tracks resources inside a Scope and attaches finalizers that run when the scope closes. acquireRelease/acquireUseRelease pair acquisition with deterministic cleanup. Effect.scoped runs a scoped effect and automatically closes the scope, running all finalizers in reverse acquisition order. Tools like addFinalizer, ensuring, and onExit provide flexible hooks for cleanup and exit-aware logic.

When to use it

• When opening files, sockets, or database connections that must be closed
• When acquiring locks or semaphores that require release
• When you need deterministic cleanup on error or interruption
• When building long-lived services with layered resources
• When composing multiple resources sequentially or in parallel

Best practices

• Use acquireRelease or acquireUseRelease for paired acquire/release patterns
• Keep finalizers simple and make them infallible; log errors instead of throwing
• Call Effect.scoped at clear boundaries (not too wide, not too narrow)
• Rely on Effect’s reverse-order finalization when composing multiple resources
• Use Layer.scoped for service-level resources tied to application lifecycle

Example use cases

• Read a file safely with acquireUseRelease to ensure the handle is closed after use
• Create a database pool with acquireRelease and expose query methods that use the pool
• Wrap a lock with acquireUseRelease to guarantee release after critical sections
• Compose acquiring DB and cache connections sequentially or in parallel inside a scoped block
• Attach logging finalizers with addFinalizer or use ensuring/onExit for exit-specific cleanup