I believe that section on the docs is more general to Workers, and not specifically related to Durab

I believe that section on the docs is more general to Workers, and not specifically related to Durable Objects. An

RpcTarget

RpcTarget

RpcTarget

RpcTarget class will need to proxy function calls to required stub. In your example,

BarRpcTarget

BarRpcTarget

BarRpcTarget

BarRpcTarget needs to extend RpcTarget, and its constructor() should add the required stub which was already pulledby the instanced Worker, and also have class methods that will essentially call

this.stub.func()

this.stub.func()

this.stub.func()

this.stub.func() on the actual DO stub. Screenshot is an example of my implementation for

RpcTarget

RpcTarget

RpcTarget

RpcTarget

hunt•2/18/25, 4:52 AM

Gotcha. Thats a neat workaround! It seems kind of awkward to have to redefine a separate rpc target interface that has the same prototype as the object, but if that’s how it has to be then I’ll live

I included the bit on the docs (partially to correct my understanding) bc from what I understand I’d think that a DO stub and an instance of an rpc target are pretty much one in the same in terms of how rpc is orchestrated, so between workers they should behave the same. I also included the BarRpcTarget just to illustrate that “if both are considered RPC stubs, why would they be treated differently?”

hunt•2/18/25, 5:04 AM

The key difference would be that DO stubs are rpc targets to a completely different compute layer (RpcTarget stays on the executing worker) which is why I thought forwarding stubs was relevant here

FFernando Barroso This is very interesting! Would you suggest using the StaticShardedDO as more of...

lambrospetrou•2/18/25, 8:37 AM

adding this global ordering type of logic on a class which extends this class

Not sure if extending is the right thing, I usually prefer composition, so another class using the sharding abstraction as its storage layer and for localized queries. The outer class is mostly to orchestrate which shards to query and do potential aggregations if needed.

do you ever see a future possibility of making the # of shards dynamic? AKA scaling storage practically infinitely?

Absolutely. It's in my plans, but I want to find a nice API for it first. Dynamic shards need splitting and merging shards over time, so ideally we should provide some DO native hooks for it. Until those are built and published I want to experiment doing it ontop but needs some time.

11984 Ford Laser I believe that section on the docs is more general to Workers, and not specifica...

lambrospetrou•2/18/25, 8:41 AM

One change I would do here if I understand your classes, is that the RpcTarget should be created from the DO side, not the caller Worker side otherwise it's tied to the Worker's lifecycle. If the DO returns an RpcTarget then method calls on the RpcTarget are going to be executed in the DO itself.

For example having a method getRpcTarget()getRpcTarget() on your DO, and calling it from a Worker allows you to pass around that returned value and anyone calling it will go back to the DO.

1984 Ford LaserOP•2/18/25, 8:43 AM

Will that pin the DO to memory while the stub is being 'used'?

11984 Ford Laser Will that pin the DO to memory while the stub is being 'used'?

lambrospetrou•2/18/25, 8:44 AM

It's the same behavior as calling a method on it directly, so it will keep it alive yes as long as someone is calling something on it. It won't stay alive forever.

1984 Ford LaserOP•2/18/25, 9:42 AM

Is there a maximum number of tags that can be assigned by a DO acting as a Hibernatable server to different WebSockets? I know each client connection can have an array of up to 10 strings assigned to it, but if I have 1000 users who each had a unique tag when their connection was being accepted, could I theoretically target each unique user via that tag?

jed•2/18/25, 3:32 PM

I have a question about billing for the SQLite storage backend. Does a row written to a table with a materialized view count as:

1 write

1 + n writes (one for the original table, one per row in the materialized view)

Jjed I have a question about billing for the SQLite storage backend. Does a row writt...

lambrospetrou•2/18/25, 3:39 PM

Any row written counts yes. Not sure what you mean by materialized view, but each index update is charged for example.

jed•2/18/25, 3:43 PM

got it, thanks! so basically the same model as d1:

Indexes will add an additional written row when writes include the indexed column, as there are two rows written: one to the table itself, and one to the index.

(btw by materialized view i mean this: https://www.sqlite.org/lang_with.html#mathint)

quan•2/18/25, 5:32 PM

hi

I just have a question regarding durable objects and websocket together, can someone help to clarify

lets say we want multiple small chat rooms,

each chat room we could ensure to have an identifier that is unique from our end

so given we have this wrangler config

[[durable_objects.bindings]]
# This is the name of the binding that will be availble in our worker
name = "CHATROOM"
class_name = "Chatroom"

[[durable_objects.bindings]]
# This is the name of the binding that will be availble in our worker
name = "CHATROOM"
class_name = "Chatroom"

then we can initiate our first room as

const roomName1 = 'unique room name 1'
env.CHATROOM.idFromName(roomName1);

const roomName1 = 'unique room name 1'
env.CHATROOM.idFromName(roomName1);

then for another room we could do

const roomName2 = 'unique room name 2'
env.CHATROOM.idFromName(roomName2);

const roomName2 = 'unique room name 2'
env.CHATROOM.idFromName(roomName2);

and so on....

so in theory, given without any sharding logic, basically we can have as many as possible rooms, as long as we could just limit a single room into maybe less than 5k connections, or whatever the connection number that we feel like its safe?

scruffy•2/18/25, 9:12 PM

the DO storage docs (https://developers.cloudflare.com/durable-objects/api/storage-api/#methods) mention that you can use the KV API in sqlite-backed DOs... does that mean that it's possible to use list by prefix (https://developers.cloudflare.com/kv/api/list-keys/#list-by-prefix)?

Sscruffy the DO storage docs (https://developers.cloudflare.com/durable-objects/api/stora...

1984 Ford LaserOP•2/18/25, 9:24 PM

KV on DO operates the same regardless of the backend

1984 Ford LaserOP•2/18/25, 9:24 PM

So yes, you can list({prefix: 'pre-')list({prefix: 'pre-')

scruffy•2/18/25, 9:34 PM

excellent, thanks!

11984 Ford Laser KV on DO operates the same regardless of the backend

scruffy•2/18/25, 9:41 PM

sorry for confusion... the KV API says that list()list() order is always lexicographical and there's no way to limit the list, but there's also https://developers.cloudflare.com/durable-objects/api/storage-api/#list which includes options such as limitlimit and reversereverse ...can these all be used together with list({prefix: 'pre-')list({prefix: 'pre-') from the KV API?

Sscruffy sorry for confusion... the KV API says that `list()` order is always lexicograph...

1984 Ford LaserOP•2/18/25, 9:42 PM

Yes. Ignore the Workers KV page when working with DO KV

11984 Ford Laser Yes. Ignore the Workers KV page when working with DO KV

scruffy•2/18/25, 9:44 PM

will do! thanks

1984 Ford LaserOP•2/18/25, 9:45 PM

They both work the same more or less, except that list()list() in DO KV returns the K:V pairs, whereas Workers KV only returns the key names (can Workers KV be changed to align with DO KV?? This is such a weird distinction between the two)

scruffy•2/18/25, 9:48 PM

at least it's that way round rather than the other

1984 Ford LaserOP•2/18/25, 9:49 PM

I also wish writes on SQLite DOs weren't 1000x more expensive than reads

scruffy•2/18/25, 10:07 PM

Not sure where better to ask this question, so apologies if it's in the wrong place... I know that the default account limit for storage is 50GB and that it can be extended by using the Limit Increase Request Form, but does anyone have any idea of any ballpark "come on now, we're definitely not giving you any more storage" limits? also, has anyone used the form and have any stories about how quick the turnaround was? (I'm still scarred on both counts from experiences with Google Cloud Platform's quota request shenanigans)

Llambrospetrou One change I would do here if I understand your classes, is that the RpcTarget s...

hunt•2/18/25, 10:24 PM

my implementation of this in case anyone is curious

hunt•2/18/25, 10:29 PM

is there a reason we have to do this instead of using the DO stub as if it were an rpc target? from the docs:

By writing a Durable Object class which inherits from the built-in type DurableObject, public methods on the Durable Objects class are exposed as RPC methods, which you can call using a DurableObjectStub from a Worker.

Sscruffy Not sure where better to ask this question, so apologies if it's in the wrong pl...

hunt•2/18/25, 10:30 PM

also am curious about this, can definitely sympathize with the PTSD

hunt•2/18/25, 10:32 PM

I know cloudflare is better than most about accommodating limit requests. I've seen a 1-2 week on turnaround from them when requesting increases on other products (not sure on DO specifically though)

Hhunt I know cloudflare is better than most about accommodating limit requests. I've s...

1984 Ford LaserOP•2/18/25, 10:57 PM

What limits have you increased, and to what new limit (if you're allowed to talk about specifics)? I haven't needed to yet, but want to make sure I'll be covered in the future

Hhunt is there a reason we have to do this instead of using the DO stub as if it were ...

1984 Ford LaserOP•2/18/25, 10:59 PM

That doc note is mostly just to define the basic way that a stub is accessed after it is initialised. The reasoning for needing RpcTarget is to do with DO stubs on their own not being serializable, but RpcTarget is

11984 Ford Laser What limits have you increased, and to what new limit (if you're allowed to talk...

hunt•2/18/25, 11:03 PM

worker size & num of workers are the ones that are top of mind (I think we got a 5x increase?)

Hhunt my implementation of this in case anyone is curious

hunt•2/19/25, 3:06 AM

a continuation on my fact finding mission:

Returning an RpcTarget from a WorkerEntrypoint shows `never` for method return types

(this isn't really a durable objects problem and more of an "rpc types" problem so I'm taking it there)

Frank•2/20/25, 1:44 AM

we needed to delete a DO from our stack today. removed binding from wrangler.ymlwrangler.yml and added a deleted_classesdeleted_classes migration, but it still complained about worker binding not removed.
ended up having to remove it from CF dashboard, then redeploy from wrangler

Frank•2/20/25, 1:44 AM

is this expected

TTyveris I'm trying to create a worker that is connected to with websockets, but then the...

boop•2/20/25, 5:52 PM

Wrap your code in backticks

```

```

TTyveris I'm trying to create a worker that is connected to with websockets, but then the...

hunt•2/20/25, 6:38 PM

the socket itself lives in the memory of the request context (same with the userId). Any state in your fetch handler wont get garbage collected until the request context is finished (or when the connection is closed)

TTyveris I'm trying to create a worker that is connected to with websockets, but then the...

hunt•2/20/25, 6:52 PM

can I ask what your use case is where you use websockets instead of something basic like an http router? do you just need to thread events back to the client as things are happening?

tornado•2/20/25, 8:20 PM

Is there any reason to delete durable objects? If I'm understanding the limits page right, I can have unlimited objects and objects that aren't being used aren't charged, why would I delete any object?

TTyveris Yeah, backend for a multiplayer game, expecting notifications and shared DOs lik...

1984 Ford LaserOP•2/20/25, 10:03 PM

You'll wanna make sure you use the Hibernation API by invoking this.state.acceptWebSocket(socket)this.state.acceptWebSocket(socket) instead of socket.accept()socket.accept() to avoid massive charges

Jacob Marshall•2/21/25, 7:05 AM

Is there any advice from the Cloudflare team around how to import a SQL dump file into a Durable Object (with SQLite backend, obviously) when the dump is larger than the memory limit for a Durable Object (128 MB)? I can't think of how this could be achieved (within a single transaction, that is). To be clear - I don't currently have this problem... but I'm trying to figure out if it's going to be one in the future. Thanks!

JJacob Marshall Is there any advice from the Cloudflare team around how to import a SQL dump fil...

lambrospetrou•2/21/25, 7:34 AM

You can use streams to process the request without having the whole file in memory. However, doing hundreds of MBs or GBs will probably need you to split it in smaller chunks otherwise you will hit cpu/time limits.
Example of streaming a file in DO: https://github.com/lambrospetrou/tiddlyflare/blob/main/src/durable-objects.ts#L281

Llambrospetrou You can use streams to process the request without having the whole file in memo...

Jacob Marshall•2/21/25, 8:20 AM

Cheers. Yeah, I figured I'd have to do it async (with streams). Hopefully someday it'll be possible without that though

JJacob Marshall Cheers. Yeah, I figured I'd have to do it async (with streams). Hopefully someda...

lambrospetrou•2/21/25, 8:21 AM

I doubt that. You will always have less memory than what people need for bulk imports. Streaming is the way to go.

Llambrospetrou I doubt that. You will always have less memory than what people need for bulk im...

Jacob Marshall•2/21/25, 8:22 AM

A man can dream can't he haha

Matt•2/21/25, 6:32 PM

So as I understand it, if you use storage.put()storage.put() multiple times without awaiting, it will group all the writes into a single round trip. If you putput to the same key multiple times without awaiting, will it write to that key multiple times or will it only write the last one?

TTyveris So with durable objects, if you plan to make api calls, it seems like its best t...

hunt•2/22/25, 3:19 AM

An approach you could consider is using a hybrid of rest and websockets. Instead of trying to create one layer of abstraction, you let rest do the thing it's good at which is handling transactional requests, and let websockets handle what it's good at which is streaming data.

Your clients would subscribe to an "event stream" DO with a user id, and when you're handling transactional requests and need to push an event to any client, you call the DO with the event and user id which then pushes that off to the client

atgctg•2/22/25, 11:40 AM

Is there a better way to make a value available in a DO's constructor? This is the only way I found:

app.get('/avatars', async c => {
  const user = c.get('user')
  c.env.uid = user.uid // is this a bad practice?
  const userObjectId = c.env.USER_OBJECT.idFromName(user.uid)
  const userObject = c.env.USER_OBJECT.get(userObjectId)
  const avatars = await userObject.getAvatars()
  return c.json(avatars)
})

app.get('/avatars', async c => {
  const user = c.get('user')
  c.env.uid = user.uid // is this a bad practice?
  const userObjectId = c.env.USER_OBJECT.idFromName(user.uid)
  const userObject = c.env.USER_OBJECT.get(userObjectId)
  const avatars = await userObject.getAvatars()
  return c.json(avatars)
})

I believe that section on the docs is more general to Workers, and not specifically related to Durab

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