Fly

Host your cluster on Fly.io: Postgres runs on a Fly Machine with a volume, and the runners run as a Fly Service, all on a private network for your stack. The runners serve their gateway at https://{name}.fly.dev.

src/Cluster.ts

import * as ClusterFly from "@alchemy.run/effect-cluster/Fly";
import * as Layer from "effect/Layer";

export const Database = ClusterFly.Database("Cluster");

export const Default = ClusterFly.MachinePool("Default", { replicas: 2 }).pipe(
  Layer.provide(Database),
);

Install @alchemy.run/fly and finish Fly setup.

Fly organizationyour profile's organization

private networkIPv6

DatabaseApp · one Machine

data

volume

DefaultFly Service

Machinerunner

Machinerunner

Runners reach Postgres and each other over the private network. Nothing outside it reaches the database; callers reach the pool at its fly.dev address.

The database

ClusterFly.Database runs Postgres on one Machine with a volume, in an App on the stack’s private network. Nothing outside the network reaches it. For Fly’s Managed Postgres, which Fly bills separately, pass its URL to Cluster.Database.fromUrl.

src/Cluster.ts

import * as ClusterFly from "@alchemy.run/effect-cluster/Fly";

export const Database = ClusterFly.Database("Cluster", {
  region: "fra",
  guest: { cpus: 2, memoryMb: 4096 },
  diskSize: 40,
});

The pool

ClusterFly.MachinePool runs a Fly Service with replicas Machines. Runners reach each other at their Machines’ private addresses, over Fly’s IPv6 network.

Call it from a Fly Service

src/Api.ts

import * as Fly from "@alchemy.run/fly";
import * as Effect from "effect/Effect";
import * as HttpServerResponse from "effect/http/HttpServerResponse";
import { Room } from "./Room.ts";

export default class Api extends Fly.Service<Api>()(
  "Api",
  { main: import.meta.url },
  Effect.gen(function* () {
    const rooms = yield* Room;
    return {
      fetch: Effect.gen(function* () {
        const lobby = yield* rooms.getByName("lobby");
        return yield* HttpServerResponse.json({ members: yield* lobby.Join({ name: "sam" }) });
      }).pipe(Effect.orDie),
    };
  }),
) {}

Every option, with its default, is in the reference: Database and MachinePool.