エラー処理

import { DurableObject } from "cloudflare:workers";

export interface Env {
	ErrorThrowingObject: DurableObjectNamespace;
}

export default {
	async fetch(request, env, ctx) {
		let userId = new URL(request.url).searchParams.get("userId") || "";

		// Retry behavior can be adjusted to fit your application.
		let maxAttempts = 3;
		let baseBackoffMs = 100;
		let maxBackoffMs = 20000;

		let attempt = 0;
		while (true) {
			// Try sending the request
			try {
				// Create a Durable Object stub for each attempt, because certain types of
				// errors will break the Durable Object stub.
				const doStub = env.ErrorThrowingObject.getByName(userId);
				const resp = await doStub.fetch("http://your-do/");

				return Response.json(resp);
			} catch (e: any) {
				if (!e.retryable) {
					// Failure was not a transient internal error, so don't retry.
					break;
				}
			}
			let backoffMs = Math.min(
				maxBackoffMs,
				baseBackoffMs * Math.random() * Math.pow(2, attempt),
			);
			attempt += 1;
			if (attempt >= maxAttempts) {
				// Reached max attempts, so don't retry.
				break;
			}
			await scheduler.wait(backoffMs);
		}
		return new Response("server error", { status: 500 });
	},
} satisfies ExportedHandler<Env>;

export class ErrorThrowingObject extends DurableObject {
	constructor(state: DurableObjectState, env: Env) {
		super(state, env);

		// Any exceptions that are raised in your constructor will also set the
		// .remote property to True
		throw new Error("no good");
	}

	async fetch(req: Request) {
		// Generate an uncaught exception
		// A .remote property will be added to the exception propagated to the caller
		// and will be set to True
		throw new Error("example error");

		// We never reach this
		return Response.json({});
	}
}