effect-io-ai

Package: effect
Module: TxSemaphore

TxSemaphore.TxSemaphore

A transactional semaphore that manages permits using Software Transactional Memory (STM) semantics, providing atomic permit acquisition and release operations within Effect transactions for concurrency control over limited resources.

When to use

Use to coordinate permit accounting atomically with other transactional state changes.

Example (Managing permits transactionally)

import { Effect, TxSemaphore } from "effect"

// Create a semaphore with 3 permits for managing concurrent database connections
const program = Effect.gen(function*() {
  const dbSemaphore = yield* TxSemaphore.make(3)

  // Acquire a permit before accessing the database
  yield* TxSemaphore.acquire(dbSemaphore)
  console.log("Database connection acquired")

  // Perform database operations...

  // Release the permit when done
  yield* TxSemaphore.release(dbSemaphore)
  console.log("Database connection released")
})

See

• make for creating a transactional semaphore
• withPermit for automatically acquiring and releasing one permit
• acquire for manually acquiring one permit transactionally

Signature

export interface TxSemaphore extends Inspectable, Pipeable {
  readonly [TypeId]: typeof TypeId
  readonly permitsRef: TxRef.TxRef<number>
  readonly capacity: number
}

Source

Since v4.0.0