Turning CDN edge into a Rack web server with ruby.wasm Kay Sawada(@remore)

Introduction

WASI WebAssembly System Interface

Local computer [status, headers, body] Browser (JS engine) Wasm runtime Any workstation (local/server) Wasm runtime(WASI)

Demo (WASI)

Turning CDN edge into a Rack web server with ruby.wasm Kay Sawada(@remore)

CDN Edge?

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Source: github.com/kateinoigakukun/ruby-compute-runtime examples/demo.rb Demo: https://ruby-compute-runtime-demo.edgecompute.app/

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🤔

Turning CDN edge into a Rack web server with ruby.wasm Kay Sawada(@remore)

Rack

Rack: A modular Ruby web server interface Rack provides a minimal, modular, and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it uni fi es and distills the bridge between web servers, web frameworks, and web application into a single method call. source: github.com/rack/rack/blob/main/README.md

Rack provides a minimal, modular, and adaptable interface for developing web applications in Ruby. By wrapping HTTP requests and responses in the simplest way possible, it uni fi es and distills the bridge between web servers, web frameworks, and web application into a single method call. source: github.com/rack/rack/blob/main/README.md

VPS ( Linux / 512MB / 20GB Disk) Http Client NGINX Unicorn Listen Connect Responding with Rack

VPS ( Linux / 512MB / 20GB Disk) Http Client NGINX Unicorn UNIX Socket Unicorn Listen Connect Sinatra App [status, headers, body]

$ cat config.ru run PersonalWebsite::App $ rackup

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VPS ( Linux / 512MB / 20GB Disk) Http Client NGINX Unicorn UNIX Socket Unicorn Listen Connect Sinatra App [status, headers, body]

Http Client Sinatra App ruby.wasm running on top of CDN Edge [status, headers, body]

CDN Edge Http Client ruby.wasm (WASI) Hostcall (WASI Implementation) demo.rb Call

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Lobster (Rack App) [status, headers, body] CDN Edge Http Client ruby.wasm (WASI) Hostcall (WASI Implementation) some_ruby_code_to_run_Rack_app.rb Call

Source: github.com/kateinoigakukun/ruby-compute-runtime examples/lobster.rb Demo: https://test-lobster.edgecompute.app/

What it takes to run a Rack App on WASI?

✅ HTTP Response body HTTP Request header HTTP Request body HTTP Response status code HTTP Response header

✅ HTTP Response body ⛔ HTTP Request header ⛔ HTTP Request body ⛔ HTTP Response status code ⛔ HTTP Response header

Add support for unsupported Hostcalls

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✅ ✅

✅ ✅

CDN Edge Http Client ruby.wasm (WASI) Hostcall (WASI Implementation) some_ruby_code_to_run_Rack_app.rb Call Lobster (Rack App) [status, headers, body]

My Blog App?

class

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⛔ C Extention

✅

Sinatra::IndifferentHash::Gem (NameError) 2024-05-06T19:00:12.023137Z INFO request{id=0}: handling request GET http://localhost:7676/ /bundle/gems/sinatra-4.0.0/lib/sinatra/indifferent_hash.rb:189:in `': uninitialized constant Sinatra::IndifferentHash::Gem (NameError) from /bundle/gems/sinatra-4.0.0/lib/sinatra/indifferent_hash.rb:41:in `’ from /bundle/gems/sinatra-4.0.0/lib/sinatra/indifferent_hash.rb:3:in `’ from /bundle/gems/sinatra-4.0.0/lib/sinatra/base.rb:21:in `require’ from /bundle/gems/sinatra-4.0.0/lib/sinatra/base.rb:21:in `’ from /exe/blog/app.rb:1:in `require’ from /exe/blog/app.rb:1:in `’ from /exe/sinatra.rb:23:in `require’ from /exe/sinatra.rb:23:in `’ 2024-05-06T19:00:12.282052Z ERROR request{id=0}: WebAssembly exited with error: error while executing at wasm backtrace: 0: 0xaf237a - !__wasi_proc_exit 1: 0xa2c64a - !_start Caused by: Exited with i32 exit status 1

indifferent_hash.rb L189 ⛔ uninitialized constant

✅

⛔ Need to adjust fi le path

✅ ✅ ✅

Sinatra Demo: https://distinctly-star-ant.edgecompute.app/

Experiments for other rack applications 🤔 tDiary runtime error: dependency to unsupported features (e.g. mkdir, socket etc. remember wasi-vfs is a read-only fi lesystem) 🤔 Rails build error: build doesn’t succeed out of the box
 (e.g. issue in installing bigdecimal) ✅ Rhino

What worked My Sinatra blog application works with CDN Edge environment if I; ✦ Added support to Compute Ruby SDK for unsupported host calls ✦ Adjusted fi le path to read blog contents from local fi lesystem

Challenges Static fi les are too big to add to wasi-vfs layer (<100MB wasm package size limit) Limited # of frameworks works out of the box ✦Limitations on fi le and network I/O etc Performance issue Gem with C Extension doesn’t work -> ✅ soon to be addressed🤞

Size & Performance File size Heap memory Avg. response time demo.wasm 35MB (with stdlib) 78MB 250ms lobster.wasm 35MB 79MB 300ms sinatra.wasm (my blog) *without images/js/css 38MB 88MB 1100ms roda.wasm 36MB 79MB 350ms

Bonus; Steps to build Compute Ruby SDK Ruby, Rust and wasi-preset-args are required $ apt update && apt upgrade $ apt-install rbenv libyaml-daev clang $ git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build $ rbenv install 3.3.0 && rbenv global 3.3.0 $ ruby -v ruby 3.3.0 (2023-12-25 revision 5124f9ac75) [x86_64-linux] $ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh && . “$HOME/.cargo/env" $ rustc —version rustc 1.77.1 (7cf61ebde 2024-03-27) $ cargo install --git https://github.com/kateinoigakukun/wasi-preset-args.git —all-features $ git clone https://github.com/kateinoigakukun/ruby-compute-runtime.git $ cd ruby-compute-runtime/examples $ bundle install # bump zlib version if needed by editing zlib.rb $ bundle exec ruby-compute-runtime demo.rb -o demo.wasm

Thanks!