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Motivation This adds networking support for the `wasm32-wasip2` target platform, which includes more extensive support for sockets than `wasm32-wasip1`. Solution The bulk of the changes are in tokio-rs/mio#1931. This patch mainly tweaks a few `cfg` directives to indicate `wasm32-wasip2`'s additional capabilities. Note that this is a draft PR until until tokio-rs/mio#1931 and rust-lang/socket2#639 have been include in stable releases of their respective projects. Also note that I've added a `wasm32-wasip2` target to CI and triaged each test which was previously disabled for WASI into one of three categories: - Disabled on both WASIp1 and p2 due to not-yet-supported features such as multithreading - Disabled on p1 but enabled on p2 - Disabled on p1 and _temporarily_ disabled on p2 due to `wasi-libc` bugfixes which have been merged but not yet included in a Rust release. I'll open an issue to re-enable them when the fixes land in Rust. Future Work In the future, we could consider adding support for `tokio::net::lookup_host`. WASIp2 natively supports asynchronous DNS lookups and is single threaded, whereas Tokio currently assumes DNS lookups are blocking and require multithreading to emulate async lookups. A WASIp2-specific implementation could do the lookup directly without multithreading. WASIp2 also supports single-threaded, asynchronous file I/O, timers, etc. We could either support those directly or wait for WASIp3's multithreading support, in which case most of `tokio::fs` (as well as `tokio::net::lookup_host`, etc.) _should_ work unchanged via `wasi-libc` and worker threads. Currently, building for WASIp2 requires RUSTFLAGS="--cfg tokio_unstable"`. Once we have a solid maintenance plan, we can remove that requirement.
Darksonn
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Motivation
This adds networking support for the
wasm32-wasip2target platform, which includes more extensive support for sockets thanwasm32-wasip1.Solution
The bulk of the changes are in tokio-rs/mio#1931. This patch mainly tweaks a few
cfgdirectives to indicatewasm32-wasip2's additional capabilities.Note that this is a draft PR until tokio-rs/mio#1931 and rust-lang/socket2#639 have been include in stable releases of their respective projects.
Also note that I've added a
wasm32-wasip2target to CI and triaged each test which was previously disabled for WASI into one of three categories:wasi-libcbugfixes which have been merged but not yet included in a Rust release. I'll open an issue to re-enable them when the fixes land in Rust.Future Work
In the future, we could consider adding support for
tokio::net::lookup_host. WASIp2 natively supports asynchronous DNS lookups and is single threaded, whereas Tokio currently assumes DNS lookups are blocking and require multithreading to emulate async lookups. A WASIp2-specific implementation could do the lookup directly without multithreading.WASIp2 also supports single-threaded, asynchronous file I/O, timers, etc. We could either support those directly or wait for WASIp3's multithreading support, in which case most of
tokio::fs(as well astokio::net::lookup_host, etc.) should work unchanged viawasi-libcand worker threads.Currently, building for WASIp2 requires
RUSTFLAGS="--cfg tokio_unstable". Once we have a solid maintenance plan, we can remove that requirement.