typespec_client_core: New `web_runtime` to support wasm32-unknown-unknown #2770

magodo · 2025-07-08T04:11:45Z

The typespec_client_core::sleep::sleep is using the async_runtime's sleep implementation, which is complicated to support wasm32, and will panic now when targeting to wasm32. Instead of make the standard_runtime to support wasm32 sleep (I wonder if it's feasible), we can instead just introduce another sleep implementation to simply use the gloo_timers::future::sleep.

Also, this PR adds a cfg_attr for conditionally remove the Send trait from the async_trait for the RetryPolicy, as the other parts of the code do.

~~Additionally, the getrandom crate will enable wasm_js features when targetting to wasm, which is necessary.~~

Fix #2754

…` when target wasm The `typespec_client_core::sleep::sleep` is using the async_runtime's sleep implementation, which is complicated to support `wasm32`, and will panic now when targeting to `wasm32`. Instead of make the `standard_runtime` to support wasm32 sleep (I wonder if it's feasible), we can instead just introduce another `sleep` implementation to simply use the `gloo_timers::future::sleep`. Also, this PR adds a `cfg_attr` for conditionally remove the `Send` trait from the `async_trait` for the `RetryPolicy`, as the other parts of the code do. Additionally, the `getrandom` crate will enable `wasm_js` features when targetting to `wasm`, which is necessary.

Copilot

Pull Request Overview

This PR adds a WebAssembly-compatible sleep implementation using gloo_timers, adjusts async_trait attributes for WASM targets, and updates dependency declarations.

Introduce a wasm-only sleep using gloo_timers::future::sleep
Add cfg_attr macros to toggle async_trait for RetryPolicy on wasm32
Update Cargo.toml files to include gloo-timers and necessary features

Reviewed Changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

File	Description
sdk/typespec/typespec_client_core/src/sleep.rs	Split `sleep` into non-WASM and WASM variants using `cfg`s
sdk/typespec/typespec_client_core/src/http/policies/retry/mod.rs	Apply `cfg_attr` to `async_trait` for WASM vs non-WASM targets
sdk/typespec/typespec_client_core/Cargo.toml	Add `gloo-timers` to WASM target dependencies
Cargo.toml	Declare `gloo-timers` with the `futures` feature at workspace root

Comments suppressed due to low confidence (1)

sdk/typespec/typespec_client_core/src/sleep.rs:36

The WASM variant of sleep is missing a doc comment; consider adding one to explain its behavior and any conversion caveats.

pub async fn sleep(duration: Duration) {

sdk/typespec/typespec_client_core/src/sleep.rs

sdk/typespec/typespec_client_core/Cargo.toml

sdk/typespec/typespec_client_core/src/sleep.rs

heaths

Better, but a couple lingering changes.

heaths · 2025-07-09T16:12:43Z

sdk/typespec/typespec_client_core/src/async_runtime/standard_runtime.rs

    ///
    /// Uses a simple thread based implementation for sleep. A more efficient
    /// implementation is available by using the `tokio` crate feature.
    #[cfg_attr(target_arch = "wasm32", allow(unused_variables))]


Seems this line is no longer needed.

If we want to do #2770 (comment), this is still needed to allow a user to select the StdRuntime even target to wasm32.

sdk/typespec/typespec_client_core/src/async_runtime/web_runtime.rs

LarryOsterman · 2025-07-09T20:20:53Z

sdk/typespec/typespec_client_core/src/async_runtime/mod.rs


 fn create_async_runtime() -> Arc<dyn AsyncRuntime> {
-    #[cfg(not(feature = "tokio"))]
+    #[cfg(target_arch = "wasm32")]


Much better, but IMHO this should probably be tied to a specific feature which is the gloo runtime, unless you can assert safely that gloo is the runtime of choice for all wasm developers (I'm not familiar enough with wasm development to have an opinion here).

This is similar to how we've tied the tokio runtime to the tokio feature - because the tokio runtime is not a globally accepted async runtime, we hide its implementation behind a feature.

@LarryOsterman The gloo-timers is provided by https://github.com/rustwasm, which is built on top of wasm-bindgen and js-sys, providing a more user friendly API. So if we really want to introduce a feature, then I'd prpose to name it "wasm-bindgen(as thespawnis based onwasm-bindgen-futures, and the sleepis based ongloo-timers, which in turn based on wasm-bindgen`).

Whilst, I believe even we use the target for this create_async_runtime(), it only means we provide a default runtime for the users. They are still able to call set_async_runtime() to choose the runtime of their choice. Otherwise, if we do:

#[cfg(feature = "wasm-bindgen")] { Arc::new(web_runtime::WasmBindgenRuntime) as Arc<dyn AsyncRuntime> } #[cfg(feature = "tokio")] { Arc::new(tokio_runtime::TokioRuntime) as Arc<dyn AsyncRuntime> } #[cfg(not(any(feature = "tokio", feature = "wasm-bindgen")))] { Arc::new(standard_runtime::StdRuntime) }

For users who target to wasm32-unknown-unknown, without specifying the wasm-bindgen feature, then they'll get a StdRuntime by default, which will only panic in any case.

I can totally get behind a wasm-bindgen feature name.

Thank you for your patience here :)

@LarryOsterman Sure, I've pushed a new commit to introduce that feature name, made the wasm dependencies optional, and only bring them by this new feature.

Going on holiday

magodo · 2025-07-22T00:46:23Z

Kindly ping @LarryOsterman

LarryOsterman · 2025-07-22T17:48:05Z

Kindly ping @LarryOsterman

Thank you for the pin. I have to finish the July SDK release and after that, I'll get to this PR. Overall it looks great

LarryOsterman · 2025-07-22T19:01:45Z

/azp run rust - pullrequest

azure-pipelines · 2025-07-22T19:02:04Z

Azure Pipelines successfully started running 1 pipeline(s).

github-actions · 2025-07-22T19:08:12Z

API Change Check

APIView identified API level changes in this PR and created the following API reviews

typespec_client_core

LarryOsterman · 2025-07-22T19:09:11Z

There's a single outstanding CI error:

2025-07-22T19:07:11.2088950Z     Checking typespec_client_core v0.6.0 (/mnt/vss/_work/1/s/sdk/typespec/typespec_client_core)
2025-07-22T19:07:11.7899314Z error[E0433]: failed to resolve: use of unresolved module or unlinked crate `web_runtime`
2025-07-22T19:07:11.7900135Z    --> sdk/typespec/typespec_client_core/src/async_runtime/mod.rs:197:18
2025-07-22T19:07:11.7900579Z     |
2025-07-22T19:07:11.7901006Z 197 |         Arc::new(web_runtime::WasmBindgenRuntime) as Arc<dyn AsyncRuntime>
2025-07-22T19:07:11.7901468Z     |                  ^^^^^^^^^^^ use of unresolved module or unlinked crate `web_runtime`
2025-07-22T19:07:11.7901872Z     |
2025-07-22T19:07:11.7902289Z     = help: if you wanted to use a crate named `web_runtime`, use `cargo add web_runtime` to add it to your `Cargo.toml`
2025-07-22T19:07:11.7902626Z

If you could please fix this, I'll get this committed.

heaths · 2025-07-30T00:22:52Z

Can we get a manual test checked in? Either a WASI that does something simple using our SDK (to make sure our SDK isn't elided)? It can be a manual test (example) ideally that returns 0 for success of anything else for an error, and we can automate it later.

This is all looking pretty good at a high-level (I need to review more thoroughly), but unless we're actually exercising it we're only getting build validation. It'd be nice to have the option - at least manually run - to actually verify it works.

magodo · 2025-07-30T01:05:51Z

@heaths Sure, I'll work on a test for this.

magodo · 2025-07-30T04:46:32Z

@heaths and @LarryOsterman, the tests are ready at my own branch, which I've created another PR (since I can't push to this branch for some reason): #2838.

Close this PR in favor of #2838

…nown (#2838) The `typespec_client_core::sleep::sleep` is using the async_runtime's sleep implementation, which is complicated to support `wasm32`, and will panic now when targeting to `wasm32`. Instead of make the `standard_runtime` to support wasm32 sleep (I wonder if it's feasible), we can instead just introduce another `sleep` implementation to simply use the `gloo_timers::future::sleep`. Also, this PR adds a `cfg_attr` for conditionally remove the `Send` trait from the `async_trait` for the `RetryPolicy`, as the other parts of the code do. Fix #2754 Supersedes: #2770 Co-authored-by: Larry Osterman <LarryOsterman@users.noreply.github.com> Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com> Co-authored-by: Heath Stewart <heaths@microsoft.com>

magodo added 2 commits July 8, 2025 14:03

fix warning

c92b92b

Copilot AI review requested due to automatic review settings July 8, 2025 04:11

magodo requested review from LarryOsterman, RickWinter, heaths and ronniegeraghty as code owners July 8, 2025 04:11

Copilot AI reviewed Jul 8, 2025

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sdk/typespec/typespec_client_core/src/sleep.rs Outdated Show resolved Hide resolved

sdk/typespec/typespec_client_core/Cargo.toml Outdated Show resolved Hide resolved

magodo added 3 commits July 8, 2025 15:04

dont unwrap

5b5607b

clean up cargo.toml

6fa709a

pass build

411faaf

LarryOsterman requested changes Jul 8, 2025

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sdk/typespec/typespec_client_core/src/sleep.rs Outdated Show resolved Hide resolved

magodo added 5 commits July 9, 2025 15:13

Define a web_runtime instead of conditionally implement sleep

6069a4f

minor

55ce372

clippy

23692dc

improve spawn

019ef31

correct error handling

5ecd47f

magodo changed the title ~~typespec_client_core: Use gloo_timers::future::sleep to impl sleep when target wasm~~ typespec_client_core: New web_runtime to support wasm32 Jul 9, 2025

magodo changed the title ~~typespec_client_core: New web_runtime to support wasm32~~ typespec_client_core: New web_runtime to support wasm32-unknown-unknown Jul 9, 2025

heaths previously requested changes Jul 9, 2025

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LarryOsterman requested changes Jul 9, 2025

View reviewed changes

introduce feature wasm-bindgen

349b3c3

LarryOsterman approved these changes Jul 22, 2025

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LarryOsterman added 3 commits July 23, 2025 09:22

Fixed build break

32a292f

Fixed clippy error

1ef0cc3

Added gloo to crates.txt

79bbd58

LarryOsterman requested review from hallipr and weshaggard as code owners July 23, 2025 17:01

magodo mentioned this pull request Jul 30, 2025

typespec_client_core: New web_runtime to support wasm32-unknown-unknown #2838

Merged

magodo closed this Jul 30, 2025

magodo mentioned this pull request Aug 26, 2025

create_async_runtime: Make cfg checks exhaustive #2937

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typespec_client_core: New web_runtime to support wasm32-unknown-unknown #2770

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typespec_client_core: New `web_runtime` to support wasm32-unknown-unknown #2770

typespec_client_core: New `web_runtime` to support wasm32-unknown-unknown #2770

magodo commented Jul 8, 2025 •

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