[Action Requested] Call for FIDL Large Message Use Cases

[Alex Zaslavsky]

TL;DR: If you have a use case for large FIDL messages, please reply to this thread or email me.

The FIDL team is interested in use cases for sending messages larger than the 64kb limit FIDL currently imposes, aka "large messages."  In particular, we are interested in specific instances where the lack of large messages has caused bugs or excess complexity in the past, or unrealized designs that are hampered by the current message size limit.  Feel free to respond to this thread with your use case, or otherwise to reach out to me directly at azasl...@google.com.

[Jeremy Manson]

Hey Alex  - you saw the bug I filed about this, right?  fxbug.dev/98783 

I'm assuming that might have something to do with why you are asking, but didn't want to take the risk.

Jeremy

On Mon, May 9, 2022 at 3:52 PM 'Alex Zaslavsky' via fidl-dev <fidl...@fuchsia.dev> wrote:

TL;DR: If you have a use case for large FIDL messages, please reply to this thread or email me.

The FIDL team is interested in use cases for sending messages larger than the 64kb limit FIDL currently imposes, aka "large messages."  In particular, we are interested in specific instances where the lack of large messages has caused bugs or excess complexity in the past, or unrealized designs that are hampered by the current message size limit.  Feel free to respond to this thread with your use case, or otherwise to reach out to me directly at azasl...@google.com.

--
All posts must follow the Fuchsia Code of Conduct https://fuchsia.dev/fuchsia-src/CODE_OF_CONDUCT or may be removed.
---
You received this message because you are subscribed to the Google Groups "fidl-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email to fidl-dev+u...@fuchsia.dev.
To view this discussion on the web visit https://groups.google.com/a/fuchsia.dev/d/msgid/fidl-dev/CAPkkwnxUdeF4RxP35JnDdJc_u5SKhdRnbzpJ%3DBNmnVXG--kgMw%40mail.gmail.com.

[Wez]

There are a few parts of the fuchsia.web APIs in which a means to automagically choose inline or large-message serialization could have made things more ergonomic, or avoided practically-valid but nonetheless artificial limits, e.g:

fuchsia.web.CookieIterator has to return cookies in "batches" since cookie data may be almost arbitrarily large, and there may be almost arbitrary numbers of cookies (see https://fuchsia.dev/reference/fidl/fuchsia.web?hl=en#CookiesIterator).

fuchsia.web defines its own Url type, at present, because of the fact that the web doesn't define a specific URL length limit (implementations vary widely in the URL lengths supported!). Elsewhere in Fuchsia's APIs URL types are defined with lower limits that are sufficient for practical purposes, and easier for implementations to work with, in the absence of more ergonomic "large message" support.

To view this discussion on the web visit https://groups.google.com/a/fuchsia.dev/d/msgid/fidl-dev/CAPYFHW3YkW%3D2jMsEAUM4Sj6nwa_NCY_7n8x%3DEUuHHfUGw3_M7g%40mail.gmail.com.

[Konstantin Pozin]

The input team may be interested in this functionality as a simpler option for supporting large payloads in future iterations of the Clipboard service.

Alex, is there a timeline for this work?

On Mon, May 9, 2022 at 6:52 PM 'Alex Zaslavsky' via fidl-dev <fidl...@fuchsia.dev> wrote:

TL;DR: If you have a use case for large FIDL messages, please reply to this thread or email me.

The FIDL team is interested in use cases for sending messages larger than the 64kb limit FIDL currently imposes, aka "large messages."  In particular, we are interested in specific instances where the lack of large messages has caused bugs or excess complexity in the past, or unrealized designs that are hampered by the current message size limit.  Feel free to respond to this thread with your use case, or otherwise to reach out to me directly at azasl...@google.com.

--

[Justin Mattson]

Some time ago component manager ran into the message limit. We were transferring component manifests from the component resolvers to component manager via FIDL, but then one exceed 64K. We switched to using VMOs I think when the manifest is too large, otherwise we still transfer over the channel.

Cheers,

Justin

To view this discussion on the web visit https://groups.google.com/a/fuchsia.dev/d/msgid/fidl-dev/CA%2Bpx2AZdM2FhqOuceKJpo-1fo732%3DJ%2BF%3DPXhySjMF_dTfA2QdQ%40mail.gmail.com.

[Alex Zaslavsky]

> Alex, is there a timeline for this work?

I would like to have an RFC draft up in the next week or two.  But the general plan in the interim would be to implement an alpha version of this feature end-to-end in one or two bindings, and then have a small number of "canary" users try it out.