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Effect Documentation

Effect 3.19 (Release)

Tim Smart
Tim Smart
Founding Engineer

Effect 3.19 has been released! This release includes a number of new features and improvements. Here’s a summary of what’s new:

@effect/cluster improvements

The @effect/cluster package has been significantly improved. The cluster system no longer requires a Shard Manager, and instead relies on the RunnerStorage service to track runner state.

To migrate, remove any Shard Manager deployments and use the updated layers in @effect/platform-node or @effect/platform-bun.

Breaking Changes

  • ShardManager module has been removed
  • EntityNotManagedByRunner error has been removed
  • Shard locks now use database advisory locks, which requires stable sessions for database connections. This means load balancers or proxies that rotate connections may cause issues.
  • @effect/platform-node/NodeClusterSocketRunner is now @effect/cluster/NodeClusterSocket
  • @effect/platform-node/NodeClusterHttpRunner is now @effect/cluster/NodeClusterHttp
  • @effect/platform-bun/BunClusterSocketRunner is now @effect/cluster/BunClusterSocket
  • @effect/platform-bun/BunClusterHttpRunner is now @effect/cluster/BunClusterHttp

New Features

  • RunnerHealth.layerK8s has been added, which uses the Kubernetes API to track runner health and liveness. To use it, you will need a service account with permissions to read pod information.

HashRing module

An experimental HashRing module has been added to the Effect core library.

This module can be used to consistently distribute keys across a set of nodes.

import { Data, HashRing, PrimaryKey } from "effect"


// The "nodes" in the hash ring need to implement PrimaryKey
class Host extends Data.Class<{
  ip: string
}> {
  [PrimaryKey.symbol]() {
    return this.ip
  }
}


// Make an empty hash ring
const ring = HashRing.make<Host>()


// Add some nodes to the ring
HashRing.add(ring, new Host({ ip: "192.168.1.1" }))
HashRing.add(ring, new Host({ ip: "192.168.1.2" }))
HashRing.add(ring, new Host({ ip: "192.168.1.3" }))


// Get the node responsible for a given key
const host = HashRing.get(ring, "my-key")!

Effect.fn.Return

A new Effect.fn.Return type utility has been added to allow typing returns on Effect.fn.

import { Effect } from "effect"


const myfn = Effect.fn("myfn")(function* (
  n: number
): Effect.fn.Return<string> {
  return `Number is ${n}`
})

Other changes

  • Graph module updates have been backported from Effect v4
  • @effect/sql-pg now uses the “pg” npm library as its backend

There were several other smaller changes made. Take a look through the CHANGELOG to see them all: CHANGELOG.

Don’t forget to join our Discord Community to follow the last updates and discuss every tiny detail!

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