Created
November 17, 2025 18:21
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| import { | |
| service, | |
| serve, | |
| type Context, | |
| RestatePromise, | |
| TerminalError, | |
| } from "@restatedev/restate-sdk"; | |
| async function* randomGreeting() { | |
| const greetings = [ | |
| "Hello", | |
| "Hi", | |
| "Greetings", | |
| "Salutations", | |
| "Howdy", | |
| "Hey there", | |
| "Good to see you", | |
| "Welcome", | |
| "Ahoy", | |
| "Yo", | |
| ]; | |
| for (const greeting of greetings) { | |
| yield greeting; | |
| } | |
| } | |
| type TaskGeneratorResult<T> = | |
| | { | |
| type: "done"; | |
| value?: undefined; | |
| } | |
| | { type: "next"; value: T } | |
| | { type: "error"; value?: undefined }; | |
| class TaskGenerator<T> { | |
| private generator: AsyncGenerator<T> | undefined = undefined; | |
| constructor( | |
| private readonly context: Context, | |
| private readonly fn: () => AsyncGenerator<T> | |
| ) {} | |
| next(): RestatePromise<TaskGeneratorResult<T>> { | |
| return this.context.run("next", async () => { | |
| if (this.generator === undefined) { | |
| this.generator = this.fn(); | |
| } | |
| try { | |
| const { value, done } = await this.generator.next(); | |
| if (done) { | |
| return { type: "done" } as const; | |
| } else { | |
| return { type: "next", value } as const; | |
| } | |
| } catch (error) { | |
| return { type: "error" } as const; | |
| } | |
| }); | |
| } | |
| } | |
| const greeter = service({ | |
| name: "greeter", | |
| handlers: { | |
| greet: async (ctx: Context, name: string) => { | |
| const generator = new TaskGenerator(ctx, randomGreeting); | |
| while (true) { | |
| const result = await generator.next(); | |
| if (result.type === "done") { | |
| break; | |
| } else if (result.type === "next") { | |
| const greeting = result.value; | |
| ctx.console.log(`${greeting}, ${name}!`); | |
| } else if (result.type === "error") { | |
| throw new TerminalError("Error generating greeting"); | |
| } | |
| } | |
| }, | |
| }, | |
| }); | |
| export type Greeter = typeof greeter; | |
| serve({ services: [greeter] }); |
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