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'?

L

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.

1

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?

J

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...

L

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.

J

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)

Q

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"

[[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);

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);

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?

S

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...

1

1984 Ford LaserOP•2/18/25, 9:24 PM

KV on DO operates the same regardless of the backend

1

1984 Ford LaserOP•2/18/25, 9:24 PM

So yes, you can

list({prefix: 'pre-')

list({prefix: 'pre-')

list({prefix: 'pre-')

list({prefix: 'pre-')

S

scruffy•2/18/25, 9:34 PM

excellent, thanks!

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

S

scruffy•2/18/25, 9:41 PM

sorry for confusion... the KV API says that

list()

list()

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

limit

limit

limit

limit and

reverse

reverse

reverse

reverse ...can these all be used together with

list({prefix: 'pre-')

list({prefix: 'pre-')

list({prefix: 'pre-')

list({prefix: 'pre-') from the KV API?

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

1

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

S

scruffy•2/18/25, 9:44 PM

will do! thanks

1

1984 Ford LaserOP•2/18/25, 9:45 PM

They both work the same more or less, except that

list()

list()

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)

S

scruffy•2/18/25, 9:48 PM

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

1

1984 Ford LaserOP•2/18/25, 9:49 PM

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

S

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...

H

hunt•2/18/25, 10:24 PM

my implementation of this in case anyone is curious

H

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...

H

hunt•2/18/25, 10:30 PM

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

H

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...

1

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 ...

1

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...

H

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

H

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)

F

Frank•2/20/25, 1:44 AM

we needed to delete a DO from our stack today. removed binding from

wrangler.yml

wrangler.yml

wrangler.yml

wrangler.yml and added a

deleted_classes

deleted_classes

deleted_classes

deleted_classes migration, but it still complained about worker binding not removed.
ended up having to remove it from CF dashboard, then redeploy from wrangler

F

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...

B

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...

H

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...

H

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?

T

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...

1

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)

this.state.acceptWebSocket(socket)

this.state.acceptWebSocket(socket) instead of

socket.accept()

socket.accept()

socket.accept()

socket.accept() to avoid massive charges

J

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...

L

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...

J

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...

L

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...

J

Jacob Marshall•2/21/25, 8:22 AM

A man can dream can't he haha

M

Matt•2/21/25, 6:32 PM

So as I understand it, if you use

storage.put()

storage.put()

storage.put()

storage.put() multiple times without awaiting, it will group all the writes into a single round trip. If you

put

put

put

put 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...

H

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

A

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)
})

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)
})

Aatgctg Is there a better way to make a value available in a DO's constructor? This is t...

L

lambrospetrou•2/22/25, 1:06 PM

I doubt this works. Did you test it? You are modifying a local variable here, not the actual env injected into your worker/DO if it happens to be created in a different machine or even a different isolate/process.
If you want data in your DO that are not in the

env

env

env

env, you need to pass them in your RPC call to the DO.

Llambrospetrou I doubt this works. Did you test it? You are modifying a local variable here, no...

A

atgctg•2/22/25, 1:09 PM

The variable shows up on env, but only tested locally.
Just would have been nice to be able to initialize it in the

constructor

constructor

constructor

constructor, I might make an

init

init

init

init method so I don't have to pass it on every call

Aatgctg The variable shows up on env, but only tested locally. Just would have been nice...

L

lambrospetrou•2/22/25, 1:11 PM

See https://developers.cloudflare.com/reference-architecture/diagrams/storage/durable-object-control-data-plane-pattern/

Cloudflare Docs

Control and data plane architectural pattern for Durable Objects · ...

Durable Objects are built on-top of Cloudflare Workers spanning several locations across our global infrastructure network.
Each Durable Object instance has its own durable storage persisted across requests, in-memory state, single-threaded execution, and can be placed in a specific region.

Llambrospetrou See https://developers.cloudflare.com/reference-architecture/diagrams/storage/du...

A

atgctg•2/22/25, 1:23 PM

That's a great resource, thanks.
So based on that, I think I should call

init(uid)

init(uid)

init(uid)

init(uid) the first time the user object is created, save the user's id to storage, and this way it will be available in storage whenever I'm calling that DO again, right? Just need to set it in the

constructor

constructor

constructor

constructor like this:

ctx.blockConcurrencyWhile(async () => {
  this.uid = await ctx.storage.get('uid')
})

ctx.blockConcurrencyWhile(async () => {
  this.uid = await ctx.storage.get('uid')
})

ctx.blockConcurrencyWhile(async () => {
  this.uid = await ctx.storage.get('uid')
})

ctx.blockConcurrencyWhile(async () => {
  this.uid = await ctx.storage.get('uid')
})

Aatgctg That's a great resource, thanks. So based on that, I think I should call `init(u...

J

James•2/22/25, 4:11 PM

I’m conservative on rpc calls and to avoid unnecessary round trips, I just pass a metadata obj to all my rpc calls as an optional arg which defaults some helpful initialization stuff to the DO

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

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