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Durable Object Time To Live

Implement a Time To Live (TTL) for Durable Object instances.

A common feature request for Durable Objects is a Time To Live (TTL) for Durable Object instances. Durable Objects give developers the tools to implement a custom TTL in only a few lines of code. This example demonstrates how to implement a TTL making use of alarms. While this TTL will be extended upon every new request to the Durable Object, this can be customized based on a particular use case.

import { DurableObject } from "cloudflare:workers";


// Durable Object
export class MyDurableObject extends DurableObject {
    // Time To Live (TTL) in milliseconds
  timeToLiveMs = 1000;


    constructor(ctx, env) {
    super(ctx, env);


    this.ctx.blockConcurrencyWhile(async () => {
    await this.ctx.storage.setAlarm(Date.now() + this.timeToLiveMs);
    });
  }


  async fetch(_request) {
      // Increment the TTL immediately following every request to a Durable Object
    await this.ctx.storage.setAlarm(Date.now() + this.timeToLiveMs);
      ...
   }


  async alarm() {
    await this.ctx.storage.deleteAll();
  }
}


// Worker
export default {
  async fetch(request, env) {
    const id = env.MY_DURABLE_OBJECT.idFromName("foo");
        const stub = env.MY_DURABLE_OBJECT.get(id)
    return await stub.fetch(request);
  },
};

To test and deploy this example, configure your wrangler.toml file to include a Durable Object binding and migration based on the namespace and class name chosen previously.

name = "durable-object-ttl"


[[durable_objects.bindings]]
name = "MY_DURABLE_OBJECT"
class_name = "MyDurableObject"


[[migrations]]
tag = "v1"
new_classes = ["MyDurableObject"]