feat(cloudflare): bind Workflows to async Workers

[sam-goodwin]

Bind class-based Cloudflare Workflows to async (non-Effect) Workers via env, mirroring how class-based Durable Objects already work.

export const AsyncWorker = Cloudflare.Worker("Async", {
  main: "./src/worker.ts",
  env: {
    MY_WORKFLOW: Cloudflare.Workflow<{ value: string }>("MyWorkflow", {
      className: "MyWorkflow",
    }),
  },
});
export type AsyncWorkerEnv = Cloudflare.InferEnv<typeof AsyncWorker>;
// env.MY_WORKFLOW is typed as the native Workflow<{ value: string }>

// src/worker.ts
import { WorkflowEntrypoint, type WorkflowEvent, type WorkflowStep } from "cloudflare:workers";

export class MyWorkflow extends WorkflowEntrypoint<AsyncWorkerEnv, { value: string }> {
  async run(event: Readonly<WorkflowEvent<{ value: string }>>, step: WorkflowStep) {
    return await step.do("greet", async () => `Hello, ${event.payload.value}!`);
  }
}

export default {
  async fetch(request: Request, env: AsyncWorkerEnv) {
    const instance = await env.MY_WORKFLOW.create({ params: { value: "world" } });
    return Response.json({ instanceId: instance.id });
  },
};

What changed

Added a props-only reference form Workflow(name, { className, scriptName }) that returns a plain WorkflowLike (parallel to DurableObjectLike), then wired it through every binding layer:

• Workflow.ts — WorkflowRefProps, WorkflowLike<Params>, isWorkflowLike guard, and the props-only runtime branch (Effect.isEffect disambiguates from the existing Effect-native form, which is unchanged).
• WorkerBinding.ts — WorkflowLike added to the WorkerBindingResource union so env accepts it.
• WorkerAsyncBindings.ts — emits the workflow binding and creates a WorkflowResource (putWorkflow) for locally-hosted workflows. Cross-script scriptName refs are binding-only (host owns the resource), same as async DOs.
• InferEnv.ts — maps WorkflowLike<Params> to the native Workflow<Params>.
• Platform.ts — the onCreate hook's requirement channel is widened from never to any so it may yield child resources. The requirement is always discharged by the surrounding stack provider context.

- onCreate?: (resource: R, props: any) => Effect.Effect<void>;
+ onCreate?: (resource: R, props: any) => Effect.Effect<void, never, any>;

Tests

New fixture + live test: a plain async Worker hosting a WorkflowEntrypoint class, bound via env, starts an instance and polls to complete. Passes against real Cloudflare (ALCHEMY_PROFILE=testing).

[alchemy-version-bot]

Install the packages built from this commit:

alchemy

bun add alchemy@https://pkg.ing/alchemy/67e1060

@alchemy.run/better-auth

bun add @alchemy.run/better-auth@https://pkg.ing/@alchemy.run/better-auth/67e1060

@alchemy.run/pr-package

bun add @alchemy.run/pr-package@https://pkg.ing/@alchemy.run/pr-package/67e1060