add Func::ready_to_call and use it in wasmtime_wasi_http::handler#13683
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dicej wants to merge 2 commits into
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add Func::ready_to_call and use it in wasmtime_wasi_http::handler#13683dicej wants to merge 2 commits into
Func::ready_to_call and use it in wasmtime_wasi_http::handler#13683dicej wants to merge 2 commits into
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This allows the caller to wait for the underlying component instance to be ready to call, i.e. for any outstanding sync calls to finish and for backpressure to be disabled, if applicable. This is particularly useful in `wasmtime_wasi_http::handler` where we need to decide whether a given worker is available to handle additional requests. Previously, that decision did not take backpressure into account, meaning the worker would continue to accept requests even when the guest had enabled backpressure. However, a worker whose guest has enabled backpressure should _not_ accept new requests; instead, it should mark itself unavailable and allow another worker to accept them.
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I'm planning to add a test for this tomorrow; leaving as a draft until then. |
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| pub(crate) struct ReadyToCall<'a, T: 'static, D: HasData + ?Sized> { | ||
| accessor: &'a Accessor<T, D>, | ||
| func: Func, | ||
| waker_key: Option<Resource<Waker>>, | ||
| } |
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Could this perhaps be modeled as a poll_* function instead of an async function to avoid the need to have a list of wakers to wake up? Similar to Accesor::poll_no_interesting_tasks which makes the API contract clear. I think one-warker-per instance is all we need for wasi:http, right?
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This allows the caller to wait for the underlying component instance to be ready to call, i.e. for any outstanding sync calls to finish and for backpressure to be disabled, if applicable.
This is particularly useful in
wasmtime_wasi_http::handlerwhere we need to decide whether a given worker is available to handle additional requests. Previously, that decision did not take backpressure into account, meaning the worker would continue to accept requests even when the guest had enabled backpressure. However, a worker whose guest has enabled backpressure should not accept new requests; instead, it should mark itself unavailable and allow another worker to accept them.