WebAssembly beyond the browser Mete Atamel Developer Advocate at Google @meteatamel atamel.dev speakerdeck.com/meteatamel

What, Why? 01

What is WebAssembly? WebAssembly (Wasm) is a binary instruction format for a stack-based virtual machine Wasm is designed as a portable compilation target for programming languages webassembly.org

What is WebAssembly? The original use cases were focused on augmenting Javascript in the browser to run native code in a fast, portable, and secure way for games, 3D graphics, etc. Supported by all major browsers webassembly.org

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CNCF 2022 Annual Survey

Wasm outside the browser There’s an attempt to get WebAssembly run outside the browser with the WASI project Instead of running apps as VMs or containers, you can run them as faster, smaller, more secure, and more portable WebAssembly modules

Faster ⇒ Wasm apps start faster than containers with no cold-start Smaller ⇒ A HelloWorld Rust app in Wasm is smaller than in an OCI container More secure ⇒ Containers execute in an allow-by-default model whereas Wasm apps execute in a deny-by-default sandbox More portable ⇒ A container built for linux/amd64 won’t work on linux/arm64 whereas a wasm32/wasi module can run on any host with a Wasm runtime

Hardware VM Hardware VM Container VM Container 2010 2000 2020 Wasm Is this the future?

Use cases www.fermyon.com/blog/four-domains-wasm

Wasm runtimes WASI 02

Wasm is a portable compilation target

Wasm modules run across CPU architectures

Wasm runtimes Many runtimes exist, some of the popular ones are: ● wasmtime: A Bytecode Alliance project ● wasmedge: A CNCF project ● wasmer: From a startup github.com/appcypher/awesome-wasm-runtimes

WebAssembly System Interface wasi.dev

POSIX-inspired Preview1 with a limited number of functions ● Read and write files (sandboxed) ● Program arguments ● Environment variables ● Hardware clock ● Random ● Sockets (limited) WebAssembly System Interface wasi.dev

But… A lot of WASI is still in proposals and limited ⇒ e.g. no socket support yet Some runtimes implement their own sockets ⇒ e.g. wasmedge has extensions for sockets in Rust, JavaScript, C Some projects try to enhance WASI ⇒ e.g. WAGI adds HTTP handlers around WASI ⇒ e.g. WASIX adds full POSIX but only supported on wasmer runtime No Garbage collection yet but there’s a proposal ⇒ github.com/WebAssembly/gc wasi.dev

Demo: Compile code to Wasm+Wasi and run on a Wasm runtime github.com/meteatamel/wasm-basics/tree/main/samples/rust-wasm github.com/meteatamel/wasm-basics/tree/main/samples/dotnet8-wasm github.com/meteatamel/wasm-basics/tree/main/samples/go-wasm github.com/jamesward/hello-kotlin-wasm/tree/wasi

Running WASI in Docker 03

Why take something smaller, faster, and more portable than a container and run it inside Docker? To combine the benefits of Wasm with the benefits of existing ecosystem with Docker, Kubernetes, etc.

runwasi Project to facilitate running Wasm managed by containerd Starting in 4.15, Docker uses runwasi to run Wasm with wasmedge, wasmtime, spin, and slight Azure AKS is also previewing Wasm node pools using runwasi with spin and slight on wasmtime WebAssembly and containerd: How it works by Nigel Poulton

Demo: Running Wasm in Docker github.com/meteatamel/wasm-basics/tree/main/samples/rust-wasm-docker

WAGI WASIX 04

WAGI allows you to run WASI binaries as HTTP handlers Write a command line application that prints a few headers, and compile it to wasm32/wasi Add an entry to the modules.toml matching URL to the Wasm module and that’s it WebAssembly Gateway Interface github.com/deislabs/wagi

WASIX – Extends WASI with most of the missing POSIX features wasix.org

Demo: Running WASI binaries as HTTP handlers with WAGI github.com/meteatamel/wasm-basics/tree/main/samples/hello-wagi

Frameworks Languages 05

Frameworks Lots of Wasm frameworks out there with different capabilities Spin by Fermyon seems to be the most comprehensive and relevant for Wasm services Handles the HTTP request/response using WAGI. Spin SDKs are available in Rust, Go and .NET. and all Wasi-compatible languages are supported github.com/fermyon/spin

Demo: Running Python with Spin on Wasm github.com/meteatamel/wasm-basics/tree/main/samples/python-spin-wasm

Language support for Wasm + WASI Rust Good support (but no Tokio or async) C, C++ Good support (but no C++ exceptions or threads) Go Support via TinyGo (but reflection is not supported) and Go 1.21 RC JavaScript Support via Shopify’s Javy on QuickJS? C#/.NET Support via experimental WASI SDK in .NET 7, wasi-experimental workload in .NET 8 preview Java Support via a fork by Fermyon of TeaVM (Java to Javascript compiler)? Kotlin Support via kowasm and Node experimental WASI API Python Support via CPython on wasm32-wasi Ruby Support via ruby.wasm www.fermyon.com/wasm-languages/webassembly-language-support enarx.dev/docs/WebAssembly/Introduction

Conclusions Wasm outside the browser is a fast changing space Standards and language support need to mature for Wasm microservices Will it replace containers? Possibly Exciting time to learn this new technology!

Thank you! Mete Atamel Developer Advocate at Google @meteatamel atamel.dev speakerdeck.com/meteatamel github.com/meteatamel/wasm-basics Feedback? bit.ly/atamel