MIO VS wasmtime

Was playing around with mio (https://github.com/tokio-rs/mio) (not that mio itself is very important here!) and was trying to implement a simple something that I've done in java before: a Reactor that you can register ReactorClients with that will get callback whenever there are events on the corresponding socket etc.

How does it compare to mio?

TcpStream gets its wake behavior by delegating to the fd wakers. The Unix wakers have a few implementations, for different platforms. On Linux and Android, epoll is used.

The real implementation details of the I/O event queue is done in mio as u/hniksic pointed out, but that's more comparable with libuv which is certainly a huge part of the Node runtime. mio and libuv have a lot of similarities (at least they used to).

My example was "twice by one developer", not "twice across all indexed repos."

A spot check shows that quite a few in your link are used specifically to ensure correct handling of Rust multi-level breaks work syntax, like https://github.com/rust-lang/rust-analyzer/blob/master/crate... , https://github.com/rust-lang/rustfmt/blob/master/tests/sourc... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... and likely more.

Another is a translation of BASIC code to Rust, using break as a form of goto. https://github.com/coding-horror/basic-computer-games/blob/e...

The example at https://github.com/tokio-rs/mio/blob/master/tests/tcp.rs is a nice one

    // Wait for our TCP stream to connect

In my program, I have about 6 different components that follow the pattern below. Basically, the components run a thread while polling on crossbeam channels, file descriptors or sockets. For polling, I am using Mio (https://github.com/tokio-rs/mio).

On the code side it's pretty much the same as C++. You have a module that defines an interface and per-platform implementations that are included depending on a "configuration conditional checks" #[cfg(target_os = "linux")] macro.

https://github.com/tokio-rs/mio/blob/c6b5f13adf67483d927b176...

Made possible by Wasi support for Mio https://github.com/tokio-rs/mio/pull/1576

Indeed! In practice it's done through the polling operation: instead of a separate poll for op1 and op2, the program essentially tells the OS "wake me when either op1 or op2 is ready" (through the epoll syscall on Linux). The mio crate implements this, and the example on the readme is basically the same loop, but written with this polling strategy in mind.

Just a documentation change, fortunately:

https://github.com/bytecodealliance/wasmtime/commits?author=...

They've submitted little documentation tweaks to other projects, too, for example:

https://learn.microsoft.com/en-us/cpp/overview/whats-new-cpp...

I don't know whether this is a formerly-legitimate open source contributor who went rogue, or a deep-cover persona spreading innocuous-looking documentation changes around to other projects as a smokescreen.

WebAssembly is extremely portable. WebAssembly runs on: all major web browsers, V8 runtimes like Node.js, and independent Wasm runtimes like Wasmtime, Lucet, and Wasmer.

cpu: 4 disk: 60 memory: 12 arch: host hostname: colima autoActivate: true forwardAgent: false # I only tested this with 'docker', not 'containerd': runtime: docker kubernetes: enabled: false version: v1.24.3+k3s1 k3sArgs: [] network: address: true dns: [] dnsHosts: host.docker.internal: host.lima.internal # Added: # - containerd-snapshotter: true (meaning containerd will be used for pulling images) docker: features: buildkit: true containerd-snapshotter: true vmType: vz rosetta: true mountType: virtiofs mountInotify: false cpuType: host # This provisioning script installs build dependencies, WasmEdge and builds the WASM runtime shims for containerd. # NOTE: this takes a LOOONG time! provision: - mode: system script: | [ -f /etc/docker/daemon.json ] && echo "Already provisioned!" && exit 0 echo "Installing system updates:" apt-get update -y apt-get upgrade -y echo "Installing WasmEdge and runwasi build dependencies:" # NOTE: packages curl, git and python3 already installed: apt-get install -y make gcc build-essential pkgconf libtool libsystemd-dev libprotobuf-c-dev libcap-dev libseccomp-dev libyajl-dev libgcrypt20-dev go-md2man autoconf automake criu pkg-config libdbus-glib-1-dev libelf-dev libclang-dev libzstd-dev protobuf-compiler apt-get clean -y - mode: user script: | [ -f /etc/docker/daemon.json ] && echo "Already provisioned!" && exit 0 # # Setting vars for this script: # # Which WASM runtimes to install (wasmedge, wasmtime and wasmer are supported): WASM_RUNTIMES="wasmedge wasmtime wasmer" # # Location of the containerd config file: CONTAINERD_CONFIG="/etc/containerd/config.toml" # # Target location for the WASM runtimes and containerd shims ($TARGET/bin and $TARGET/lib): TARGET="/usr/local" # # Install rustup: # echo "Installing rustup for building runwasi:" curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain none -y source "$HOME/.cargo/env" # # Install selected WASM runtimes and containerd shims: # [[ -z "${WASM_RUNTIMES// /}" ]] && echo "No WASM runtimes selected - exiting!" && exit 0 git clone https://github.com/containerd/runwasi echo "Installing WASM runtimes and building containerd shims: ${WASM_RUNTIMES}:" sudo mkdir -p /etc/containerd/ containerd config default | sudo tee $CONTAINERD_CONFIG >/dev/null for runtimeName in $WASM_RUNTIMES; do case $runtimeName in wasmedge) echo "Installing WasmEdge:" curl -sSfL https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | sudo bash -s -- -p $TARGET echo echo "`wasmedge -v` installed!" ;; wasmtime) echo "Installing wasmtime:" curl -sSfL https://wasmtime.dev/install.sh | bash sudo cp .wasmtime/bin/* ${TARGET}/bin/ rm -rf .wasmtime echo "`wasmtime -V` installed!" ;; wasmer) echo "Installing wasmer:" curl -sSfL https://get.wasmer.io | sh sudo cp .wasmer/bin/* ${TARGET}/bin/ sudo cp .wasmer/lib/* ${TARGET}/lib/ rm -rf .wasmer echo "`wasmer -V` installed!" ;; *) echo "ERROR: WASM runtime $runtimeName is not supported!" exit 1 ;; esac cd runwasi echo "Building containerd-shim-${runtimeName}:" cargo build -p containerd-shim-${runtimeName} --release echo "Installing containerd-shim-${runtimeName}-v1:" sudo install ./target/release/containerd-shim-${runtimeName}-v1 ${TARGET}/bin sudo ln -sf ${TARGET}/bin/containerd-shim-${runtimeName}-v1 ${TARGET}/bin/containerd-shim-${runtimeName}d-v1 sudo ln -sf ${TARGET}/bin/containerd-shim-${runtimeName}-v1 ${TARGET}/bin/containerd-${runtimeName}d echo "containerd-shim-${runtimeName} installed." cd .. echo "[plugins.\"io.containerd.grpc.v1.cri\".containerd.runtimes.${runtimeName}]" | sudo tee -a $CONTAINERD_CONFIG >/dev/null echo " runtime_type = \"io.containerd.${runtimeName}.v1\"" | sudo tee -a $CONTAINERD_CONFIG >/dev/null done echo "containerd WASM runtimes and shims installed." # # Restart the systemctl services to pick up the installed shims. # NOTE: We need to 'stop' docker because at this point the actual daemon.json config is not yet provisioned: # echo "Restarting/reloading docker/containerd services:" sudo systemctl daemon-reload sudo systemctl restart containerd sudo systemctl stop docker sshConfig: true mounts: [] env: {}

When you say wasm container, you mean something like wasmtime that provides a non-browser wasm runtime?

https://github.com/bytecodealliance/wasmtime

We can't run this directly from the command line unless we install some runtime like wasmtime:

The roadmap I linked above. The WASI folks have done a poor job at communicating, no doubt, but I'm surprised someone like yourself literally building a competitor spec isn't following what they are doing closely.

Just for you I did some googling: see here[0] for the current status of WASI threads overall, or here[1] and here[2] for what they are up to with WASI in general. In this PR[3] you can see they enabled threads (atomic instructions and shared memory, not thread creation) by default in wasmtime. And in this[4] repository you can see they are actively developing the thread creation API and have it as their #1 priority.

If folks want to use WASIX as a quick and dirty hack to compile existing programs, then by all means, have at it! I can see that being a technical win. Just know that your WASIX program isn't going to run natively in wasmtime (arguably the best WASM runtime today), nor will it run in browsers, because they're not going to expose WASIX - they're going to go with the standards instead. so far you're the only person I've met that thinks exposing POSIX fork() to WASM is a good idea, seemingly because it just lets you build existing apps 'without modification'.

Comical you accuse me of being polarizing, while pushing for your world with two competing WASI standards, two competing thread creation APIs, and a split WASM ecosystem overall.

[0] https://github.com/bytecodealliance/jco/issues/247#issuecomm...

[1] https://bytecodealliance.org/articles/wasmtime-and-cranelift...

[2] https://bytecodealliance.org/articles/webassembly-the-update...

[3] https://github.com/bytecodealliance/wasmtime/pull/7285

[4] https://github.com/WebAssembly/shared-everything-threads

Thanks for the question!

Spin could definitely run in more places than what we have pre-built binaries for. Specifically, we could run on all platforms Wasmtime supports today (https://github.com/bytecodealliance/wasmtime/releases/tag/v1...), including RISC and S390X, for example.

And while we have been experimenting a bit with running Spin on RISC, we haven't really had the bandwidth or requirement to build a production build for those yet.

Are you interested in a specific operating system or CPU architecture? Would love to understand your scenario.

> I used to think we'd eventually get to capability based security, but now I see we'll always be stuck with application permission flags, the almost worthless bastard cousin, instead.

My hope is that WASI will introduce capability based security to the mainstream on non-mobile computers [0] - it might just take some time for them to get it right. (And hopefully no half-baked status-quo-reinforcing regressive single—runtime-backed alternatives win in the meantime.)

[0]: https://github.com/bytecodealliance/wasmtime/blob/main/docs/...

WasmTime finished finished the RFC for the implementation details in June: https://github.com/bytecodealliance/wasmtime/issues/5032

[3]: https://github.com/bytecodealliance/wasmtime/pull/2611