Wondering about the availability of durable objects in all PoPs? Experiments for me right now in Australia create DOs in Singapore. I remember reading somewhere that supporting all locations was challenging. There was some talk of ephemeral DOs (without the storage) that where locked to a location is something like that still being considered?

for current state you can check: https://where.durableobjects.live/

Thank you!

that's so cool! but how does it know the location of DO? I thought we cannot retrieve the colo of a DO?

You can run

fetch('https://1.1.1.1/cdn-cgi/trace')

inside the DO 🙂

Nice 😀 that solves one of my potential problems

Hi all, looking for a couple more beta testers of a new Durable Object library that we'll be releasing shortly. Please DM if you're interested. Ideally looking for users who already have DO familiarity & have (or plan to) large workloads and/or synchronization needs

Cool! What kind of synchronisation?

syncs across objects 🙂

Are DOs a good replacement for Ably (realtime websocket channels)? I currently have a Cloudflare worker endpoint and I'm using Ably to mass inform clients to hit the endpoint again to get updated data.

If the websocket knows you have updated data why not use that to send the data to the clients?

Each client gets back a custom response based on the client's identity

Whenever the data changes, the response needs to be recomputed for each client

I would prefer to push the recomputed data if I could

Instead of making each client re-pull it

Clients can stay connected to a DO via websocket, yes, just as with Ably. The question is more how would the DO know it needs to inform the clients?

Could I not communicate to the DO when new data is available to inform it to update clients?

If you have a single DO for all clients, sure. Don't know what scale you need.

I don't have a good handle on my scale either as I'm still an early product. My scale is my customers's scale, so whatever number of live users they have on their site or app. Right now I don't have scaling bottlenecks in my architecture.

Is there an understanding of how DOs can scale?

DOs scale horizontally, so it's best if the workload is distributed across many of them. Meaning if you can partition your data in a way that each DO only handles a small portion, and each client only connects to one or a few of them. E.g. if each chatroom is a separate DO, you can have an unlimited (almost) number of chatrooms, and each room only needs to be able to handle the clients in that room.

Gotcha. My data is partitioned around my customers and the scale per customer is their user base, so I could likely have very large partitions.

@User Nice, I'm currently doing some syncing, between one Lobby DO and multiple Room DOs. Having to post dummy URLs between DOs is a bit.. annoying, but if this library helps with that then I'd love to try it out 🙂

It helps exactly with that 🙂

Here's also a snippet that gives you a bit more details (Based on the code of where.durableobject.live)

ts
/**
 * Colo interface from https://speed.cloudflare.com/locations
 */
export interface Colo {
  iata: string;
  lat?: number;
  lon?: number;
  cca2: string;
  region?: string;
  city: string;
}

/**
 * Gets the current colo of the worker or durable object.
 */
export async function getColo(): Promise<Colo> {
  // This endpoint returns an array with all of Cloudflare's network locations.
  const coloUrl = "https://speed.cloudflare.com/locations";
  const res = await fetch(coloUrl);

  // Extract the colo which sent us the response. The colo is included in the CF-RAY response header.
  // CF-RAY response header example: 1234567890-AMS
  const parts = res.headers.get("CF-RAY").split("-");
  const colo = parts[parts.length - 1];

  const colos: Colo[] = await res.json();
  return colos.find((x) => x.iata === colo);
}

@User a setInterval example in your gist would be great, I can't wrap my head around getting it to work / cancel properly.

thanks, that's interesting; wondered how to get all the CF colos eventually, another small problem solved

I hope someday someone writes all theses tricks together as a blogpost or a recipe list, there si a lot of tribal knowledge about DOs (of course more docs will help, but they'll never cover all the community knowledge)

https://discord.com/channels/595317990191398933/773219443911819284/884896621173813290 bumping this for the morning crowd, also star it to get it in #874704644104941569 please!

I took a glance at the readme page, it looks super cool! I'm actually working something quite similar, hope I can find the time this week to play around with it!