Lifecycle

SpacetimeDB: Lifecycle ↗

Lifecycle hooks can be declared in the module config and implemented with StdbBuilder.lifecycle(...).

import * as Effect from "effect/Effect"
import * as Stdb from "effect-spacetimedb"

const Lifecycle = {
  init: Stdb.StdbFn.init().spec,
  clientConnected: Stdb.StdbFn.clientConnected().spec,
  clientDisconnected: Stdb.StdbFn.clientDisconnected().spec,
}

const Module = Stdb.StdbModule.make("app", {
  lifecycle: Lifecycle,
})
const { ReducerCtx } = Module

const LifecycleLive = Stdb.StdbBuilder.lifecycle(Module, {
  // Runs once when the module is first published.
  init: () => Effect.log("module initialized"),
  // clientConnected / clientDisconnected run as the joining or leaving client,
  // so ReducerCtx identifies who it was.
  clientConnected: Effect.fn(function* () {
    const ctx = yield* ReducerCtx
    yield* Effect.log(`client connected: ${ctx.connectionId}`)
  }),
  clientDisconnected: Effect.fn(function* () {
    const ctx = yield* ReducerCtx
    yield* Effect.log(`client disconnected: ${ctx.connectionId}`)
  }),
})

Lifecycle hooks are first-class module declarations, not loose exports. At most one init, clientConnected, and clientDisconnected hook can be present in a built module, and handlers are checked against the module’s Effect capability scope.