Hmm. It just occurred to me this could totally be done with WAE

PhoenixSpaceOP•10/27/25, 8:47 PM

Probably much simpler

1984 Ford Laser•10/27/25, 8:47 PM

I wonder if you could store the entire 300k events as a single object in R2 then just process them when you need them via streaming into a Worker?

PPhoenixSpace Hmm. It just occurred to me this could totally be done with WAE

1984 Ford Laser•10/27/25, 8:47 PM

or this maybe

PhoenixSpaceOP•10/27/25, 8:48 PM

Yeah, I’ll probably just use WAE lmao

1984 Ford Laser•10/27/25, 8:48 PM

300k events for a leaderboard is wild to me, what are you doing exactly lol? If youre allowed to talk a bit more about it

1984 Ford Laser•10/27/25, 8:49 PM

ahh I see WAE is only 0.25 per mil writes

PhoenixSpaceOP•10/27/25, 8:50 PM

Honestly I don’t know a lot of details. Friend came to me and asked for help with the data pipeline. As far as I know it’s some tech related challenge thing, and certain events generate milestones they have to track with some light validation in worker. AFAIK their reasoning for not batching was concern someone would be able to edit it on the computer before the batch is pushed (this seems like something you can design around but I’m not making that part)

11984 Ford Laser ahh I see WAE is only 0.25 per mil writes

1984 Ford Laser•10/27/25, 8:52 PM

oh and you only get charged per read query not per row thats kinda crazy

PhoenixSpaceOP•10/27/25, 8:53 PM

tbh it sounded like a fun excuse to do more with cloudflare and that’s all I really paid attention to

PPhoenixSpace tbh it sounded like a fun excuse to do more with cloudflare and that’s all I rea...

1984 Ford Laser•10/27/25, 8:53 PM

Honestly if you ignored costs there's probably a dozen different ways to use CF products to do this

1984 Ford Laser•10/27/25, 8:53 PM

I'll always take more opportunities to build diff stuff on CF

PhoenixSpaceOP•10/27/25, 8:54 PM

Same

PPhoenixSpace Yeah, I’ll probably just use WAE lmao

Hard@Work•10/27/25, 9:01 PM

Though note WAE can perform sampling

LLarry I had a chance over the last week to do a deep dive on Cap'n Web. Here is my mul...

1984 Ford Laser•10/27/25, 9:23 PM

I found this really interesting, not only to help me understand more generally how RPC works under the hood, but also how I can improve some of my dx and implement useful patterns like OCAN. Definitely can't wait to see where you take Lumenize, unless CapnWeb takes over (which it seems like you aren't convinced on the standard yet)

hollowaya•10/27/25, 9:56 PM

does anyone know if the KV backend DOs have a 30s limit, or if they also respect the 5m limit if set? docs are kinda ambiguous

hollowaya•10/27/25, 10:56 PM

also, does anyone know if memory or logging of out-of-memory are improved on the sqlite backend?

Hhollowaya also, does anyone know if memory or logging of out-of-memory are improved on the...

1984 Ford Laser•10/27/25, 11:05 PM

There's basically no reason to still be using the old KV backend

hollowaya•10/27/25, 11:11 PM

Asking because we're running into DO issues with memory exceeded (on requests that aren't using 128mb of memory), but it's not worth the migration (deleting all DO objects and remaking under a diff name) for us if the only diff is the storage change

Larry•10/27/25, 11:42 PM

I've never actually seen this be a problem for me (after panicking about it when I first started using DOs) but more than one instance of the same DO can share the same 128MB. Cloudflare must be smart about sensing that and not loading them that way if they are prone to use more than half the memory but do you think that might be going on?

Larry•10/27/25, 11:45 PM

You can sense if that is happening by storing a counter in global context. That global context is shared across instances if they are running in the same 128MB memory.

Larry•10/28/25, 12:44 AM

Is there a nuanced writeup comparing and contrasting extending RpcTarget vs DurableObject?

LLarry You fire and forget to offload it to another DO whose only purpose is to send fe...

Larry•10/28/25, 1:22 AM

As promised, we just released

@lumenize/proxy-fetch

@lumenize/proxy-fetch

which offloads fetch requests to a Worker via Queues.

Introduction | Lumenize

Cost-effective external API calls from Durable Objects using Cloudflare Queues

Larry•10/28/25, 1:24 AM

Here's a diagram showing how it works

Jehu•10/28/25, 4:24 AM

Sad DX has to be such that we need to build things like proxy-fetch.

We either use waitUntil, queues or workflows to avoid wall-time specially for inference call scenarios. C'est la vie.

We need an out-of-the-box solution.

LLarry As promised, we just released [`@lumenize/proxy-fetch`](https://lumenize.com/doc...

1984 Ford Laser•10/28/25, 7:31 AM

What's the delay from sending off the proxy fetch to it being returned? My issue with Queues was always that few seconds delay while the queue is receiving the event

11984 Ford Laser What's the delay from sending off the proxy fetch to it being returned? My issue...

Larry•10/28/25, 9:42 AM

It varies wildly, but with this Queues-based variety, you should count on 2-3 seconds p90. As @Jehu wrote, just making the fetch from the DO is often the right choice. It could turn out that the diagram might be the most valuable thing about pushing this out, but maybe someone will find it useful.

We're also working on the docs for a variety that's based upon Durable Objects. Its latency depends upon where in the world the proxy DO is in relation to the DO that makes the fetch. I don't have numbers, but my guess is that same co-lo, you'd be talking no more than 20ms latency, on top of the fetch itself of course. You can stand up an instance of it in each region, which will cost ~$4/month each from Cloudflare but we're hoping to also offer it as a service for about the same, except we take care of scaling and world-wide co-lo. Sad part is, we're essentially re-inventing Queues.

That version also does streams and SSE but we are struggling to live test demo those features and may only release that as a service.

Original message was deleted

1984 Ford Laser•10/28/25, 10:14 AM

How do I tag mods or is there a ? command for spam like this

11984 Ford Laser How do I tag mods or is there a ? command for spam like this

Larry•10/28/25, 1:16 PM

There is a report post feature in the Discord

...

...

dropdown. I reported as soon as I saw it. Someone at Cloudflare deleted soon after my report.

Larry•10/28/25, 1:19 PM

What's the error you'll get if you exceed the pending outgoing fetch limit? I know the current in flight limit is 6, but I've tried getting 200 in flight at the same time and I haven't exceeded that limit or gotten an error. This is in vitest-pool-workers so maybe I need to experiment in prod?

LLarry What's the error you'll get if you exceed the pending outgoing fetch limit? I kn...

1984 Ford Laser•10/28/25, 1:20 PM

Definitely wanna test in prod first

LLarry What's the error you'll get if you exceed the pending outgoing fetch limit? I kn...

lambrospetrou•10/28/25, 1:21 PM

You don't get an error when you have more than 6, they just get queued and once one completes another one runs. The error is when you are more than 1000 by default I think.

Llambrospetrou You don't get an error when you have more than 6, they just get queued and once ...

Larry•10/28/25, 1:25 PM

Thanks. What are the details of the error so I can catch it specifically? Or should I just send 2000 and see?

Chris•10/28/25, 6:45 PM

2 [ sse / durable object ] questions please. 1) There is a lovely blog about hibernating ws's, is this something we should also do for sse's? 2) How does pricing for sse's work please?

ty!!!

CChris 2 [ sse / durable object ] questions please. 1) There is a lovely blog about hib...

Hard@Work•10/28/25, 6:48 PM

Hibernation is only available for WebSockets at the moment

HHard@Work Hibernation is only available for WebSockets at the moment

Chris•10/28/25, 7:50 PM

Thanks for the info! Do we get charged for like amount of time writers exist in do's, here's the simple prototype that I'd like to build up, unless it'll we are charged for each moment the do exists!

worker:

import { DurableObject } from "cloudflare:workers"

export default {
  async fetch(request, env, ctx): Promise<Response> {
    const stub = env.MY_DURABLE_OBJECT.getByName("foo");

    if (request.url.includes('/subscribe')) return stub.subscribe(request)
    else if (request.url.includes('/message')) return await stub.message(request) 
    else return new Response(html, {headers: {'content-type': 'text/html'}})
  },
} satisfies ExportedHandler<Env>

import { DurableObject } from "cloudflare:workers"

export default {
  async fetch(request, env, ctx): Promise<Response> {
    const stub = env.MY_DURABLE_OBJECT.getByName("foo");

    if (request.url.includes('/subscribe')) return stub.subscribe(request)
    else if (request.url.includes('/message')) return await stub.message(request) 
    else return new Response(html, {headers: {'content-type': 'text/html'}})
  },
} satisfies ExportedHandler<Env>

html:

const html = `
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>Durable Object SSE Test</title>
</head>
<body>
  <h1>New Durable Object SSE Test</h1>
  <button id="send">Send Message</button>
  <div id="log" style="margin-top: 1em; white-space: pre;"></div>

  <script>
    const log = (msg) => {
      const el = document.getElementById('log');
      el.textContent += msg + "\\n";
    };

    // Subscribe to the stream
    const es = new EventSource('/subscribe');
    es.onopen = () => log('[connected]');
    es.onerror = (err) => log('[error] ' + JSON.stringify(err));
    es.onmessage = (e) => log('[message] ' + e.data);

    // Send a message to broadcast
    document.getElementById('send').addEventListener('click', async () => {
      const res = await fetch('/message', {
        method: 'POST',
        body: JSON.stringify({ time: new Date().toISOString() }),
        headers: { 'Content-Type': 'application/json' }
      });
      log('[sent] ' + (await res.text()));
    });
  </script>
</body>
</html>
`

const html = `
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>Durable Object SSE Test</title>
</head>
<body>
  <h1>New Durable Object SSE Test</h1>
  <button id="send">Send Message</button>
  <div id="log" style="margin-top: 1em; white-space: pre;"></div>

  <script>
    const log = (msg) => {
      const el = document.getElementById('log');
      el.textContent += msg + "\\n";
    };

    // Subscribe to the stream
    const es = new EventSource('/subscribe');
    es.onopen = () => log('[connected]');
    es.onerror = (err) => log('[error] ' + JSON.stringify(err));
    es.onmessage = (e) => log('[message] ' + e.data);

    // Send a message to broadcast
    document.getElementById('send').addEventListener('click', async () => {
      const res = await fetch('/message', {
        method: 'POST',
        body: JSON.stringify({ time: new Date().toISOString() }),
        headers: { 'Content-Type': 'application/json' }
      });
      log('[sent] ' + (await res.text()));
    });
  </script>
</body>
</html>
`

Chris•10/28/25, 7:51 PM

durable object:

export class MyDurableObject extends DurableObject<Env> {
  encoder = new TextEncoder()
  writers: Map<string, WritableStreamDefaultWriter<Uint8Array>> = new Map()


  constructor(ctx: DurableObjectState, env: Env) {
    super(ctx, env);
  }

  subscribe(request: Request): Response {
    const stream = new IdentityTransformStream()
    const writer = stream.writable.getWriter()
    const id = crypto.randomUUID()
    this.writers.set(id, writer)

    const headers = {
      'Connection': 'keep-alive',
      'Cache-Control': 'no-cache',
      'Content-Type': 'text/event-stream',
      'Access-Control-Allow-Origin': request.headers.get('Origin')!, // secured @ worker (outside world portal)
    }

    // initial comment
    writer.write(this.encoder.encode(`: connected\n\n`))

    // clean up on abort
    request.signal.addEventListener('abort', () => {
      writer.close()
      this.writers.delete(id)
    })

    return new Response(stream.readable, { headers })
  }


  async message(request: Request): Promise<Response> {
    const data = await request.text()

    for (const [_, writer] of this.writers) {
      writer.write(this.encoder.encode(`data: ${data}\n\n`))
    }

    return new Response('good', {
      status: 200,
      headers: {
        'Access-Control-Allow-Headers': 'Content-Type',
        'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
        'Access-Control-Allow-Origin': request.headers.get('Origin')!,
      },
    })
  }
}

export class MyDurableObject extends DurableObject<Env> {
  encoder = new TextEncoder()
  writers: Map<string, WritableStreamDefaultWriter<Uint8Array>> = new Map()


  constructor(ctx: DurableObjectState, env: Env) {
    super(ctx, env);
  }

  subscribe(request: Request): Response {
    const stream = new IdentityTransformStream()
    const writer = stream.writable.getWriter()
    const id = crypto.randomUUID()
    this.writers.set(id, writer)

    const headers = {
      'Connection': 'keep-alive',
      'Cache-Control': 'no-cache',
      'Content-Type': 'text/event-stream',
      'Access-Control-Allow-Origin': request.headers.get('Origin')!, // secured @ worker (outside world portal)
    }

    // initial comment
    writer.write(this.encoder.encode(`: connected\n\n`))

    // clean up on abort
    request.signal.addEventListener('abort', () => {
      writer.close()
      this.writers.delete(id)
    })

    return new Response(stream.readable, { headers })
  }


  async message(request: Request): Promise<Response> {
    const data = await request.text()

    for (const [_, writer] of this.writers) {
      writer.write(this.encoder.encode(`data: ${data}\n\n`))
    }

    return new Response('good', {
      status: 200,
      headers: {
        'Access-Control-Allow-Headers': 'Content-Type',
        'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
        'Access-Control-Allow-Origin': request.headers.get('Origin')!,
      },
    })
  }
}

CChris 2 [ sse / durable object ] questions please. 1) There is a lovely blog about hib...

Larry•10/28/25, 8:16 PM

I have been pestering the agents team about this since I become a member of Anthropic's MCP Transports Working Group. We either need hibernating SSE's or we need to get my WebSocket SEP approved.

Larry•10/28/25, 8:18 PM

For now, I'm working on productionalizing my proxyFetch. I have the Queue based one out. The SSE one is coming soon. https://lumenize.com/docs/proxy-fetch/

Introduction | Lumenize

Cost-effective external API calls from Durable Objects using Cloudflare Queues

Aalgads Ive been having some weird performance issues during testing a new app. The lat...

1984 Ford Laser•10/28/25, 8:23 PM

I had this issue just last week, the ID will always spawn in WEUR regardless of deletion of storage or anything. Best suggestion has been to use a different ID I guess (which might not work depending on use case)

1984 Ford Laser•10/28/25, 8:24 PM

I was getting DOs spawning in Perth Australia instead of Melbourne where I live or Sydney, so I was getting hit with 100s of ms extra request time

11984 Ford Laser I had this issue just last week, the ID will always spawn in WEUR regardless of ...

Chaika•10/28/25, 8:31 PM

well the DO won't move once it's created, and even deleting the storage it still sticks around for a while, at least a few hours last I knew, not sure if there's any better docs/knowledge on that but afaik it's all heavily cached once created.

I think here some location hints might be more helpful if your users are from a specific area, to force it consistently

Chaika•10/28/25, 8:32 PM

fwiw there was a decent bit of request rerouting from north america -> europe earlier today (requests being sent in North America being handled in Europe usually due to capacity reasons), like over 50% going to Europe for 3 hours or so peak US time (for free plan, slightly less for pro/biz/etc, going up the plans). It's calmed down now, but if your request gets bounced over there, Worker runs over there, placement of the DO will be near there

Aalgads It's still happening - I am in NY and about an hour ago I was making calls to EW...

Chaika•10/28/25, 8:55 PM

yea it's still happening but has just gone down, if the primary concern of yours is this rerouting it's not very often it's done, only recently there's been some of it. It's pretty transient but yea annoying to work around for still. Ultimately during the rerouting the placing of the object in Europe is good placement, since going back to NA would be further, it's just after it gets messy

Chaika•10/28/25, 8:56 PM

last major time it was happening was August (for North America), and then nothing for the months before, going to vary depending on the exact location you're hitting though

Aalgads Ive been having some weird performance issues during testing a new app. The lat...

Chaika•10/28/25, 9:10 PM

I was trying to find a good reference and as far as I know and can find, the ID and the location exists forever even if you delete all storage, won't be re-placed
durable-objects

Storage gone, the object lives forever though

I have some DOs at least a month old which say they have no storage that still are "around" in CF's Durable Objects Objects list api.

There's some downstream constraints from this like re-creating R2 buckets with the same name (which use DOs) never change regions, I imagine from the same reason...

Larry•10/29/25, 12:56 AM

We release the Queues based variant of proxy-fetch yesterday. Today we release the Durable Objects based one. latency of 50-100ms compared to 200ms to 3 seconds for the Queue based one. Stay tuned for the SSE one next. See: https://lumenize.com/docs/proxy-fetch/durable-object

Durable Object | Lumenize

Use a dedicated proxy DO to handle external fetches

Larry•10/29/25, 1:42 AM

import { DurableObject } from "cloudflare:workers" export default { async fetch(request, env, ctx): Promise<Response> { const stub = env.MY_DURABLE_OBJECT.getByName("foo"); if (request.url.includes('/subscribe')) return stub.subscribe(request) else if (request.url.includes('/message')) return await stub.message(request) else return new Response(html, {headers: {'content-type': 'text/html'}}) }, } satisfies ExportedHandler<Env>

export class MyDurableObject extends DurableObject<Env> { encoder = new TextEncoder() writers: Map<string, WritableStreamDefaultWriter<Uint8Array>> = new Map() constructor(ctx: DurableObjectState, env: Env) { super(ctx, env); } subscribe(request: Request): Response { const stream = new IdentityTransformStream() const writer = stream.writable.getWriter() const id = crypto.randomUUID() this.writers.set(id, writer) const headers = { 'Connection': 'keep-alive', 'Cache-Control': 'no-cache', 'Content-Type': 'text/event-stream', 'Access-Control-Allow-Origin': request.headers.get('Origin')!, // secured @ worker (outside world portal) } // initial comment writer.write(this.encoder.encode(`: connected\n\n`)) // clean up on abort request.signal.addEventListener('abort', () => { writer.close() this.writers.delete(id) }) return new Response(stream.readable, { headers }) } async message(request: Request): Promise<Response> { const data = await request.text() for (const [_, writer] of this.writers) { writer.write(this.encoder.encode(`data: ${data}\n\n`)) } return new Response('good', { status: 200, headers: { 'Access-Control-Allow-Headers': 'Content-Type', 'Access-Control-Allow-Methods': 'GET, POST, OPTIONS', 'Access-Control-Allow-Origin': request.headers.get('Origin')!, }, }) } }