Add Go and C# .NET language support

[richardkiene]

Summary

Add support for building and running Go and C# .NET applications as WASM modules. Unlike Python and Node.js which require interpreter runtimes, both Go and .NET compile directly to WASM.

Research

Go

• Go 1.21+ has native WASI support via GOOS=wasip1 GOARCH=wasm
• Go 1.24 (2025) adds WASI reactor support with go:wasmexport directive and -buildmode=c-shared for long-running HTTP services
• Compiles directly to WASM - no interpreter runtime needed
• Limitation: WASI preview 1 has partial socket support

Build command:

GOOS=wasip1 GOARCH=wasm go build -o app.wasm

Sources:

• WASI support in Go
• Go 1.24 expands support for Wasm
• Go WebAssembly Wiki

C# .NET

• .NET 8 has experimental WASI workload (wasi-experimental)
• .NET 10 (Nov 2025) has first-class WASI support with dedicated WASM team, Native AOT
• Uses Wasi.Sdk NuGet package or componentize-dotnet from Bytecode Alliance
• Native AOT compilation produces standalone WASI-compliant .wasm files
• No interpreter runtime needed

Build approach:

dotnet add package Wasi.Sdk --prerelease
dotnet build

Sources:

• dotnet-wasi-sdk
• Running .NET in WebAssembly
• C# in WebAssembly - Fermyon

Implementation Plan

1. Go Support

Add Go builder in CLI (fabricks/src/builders/go.rs):

• Detect Go projects (go.mod)
• Run GOOS=wasip1 GOARCH=wasm go build
• For HTTP services (Go 1.24+), use -buildmode=c-shared for reactor mode

2. .NET Support

Add .NET builder in CLI (fabricks/src/builders/dotnet.rs):

• Detect .NET projects (.csproj)
• Ensure Wasi.Sdk package is added
• Run dotnet build with appropriate WASI configuration

3. Examples

Create example projects:

• examples/go-hello/ - Simple command module
• examples/go-http/ - HTTP service using Go 1.24 reactor mode
• examples/dotnet-hello/ - Simple command module
• examples/dotnet-http/ - HTTP service

4. No Runtime Layer Needed

Unlike Python/Node.js interpreted runtimes, Go and .NET compile directly to WASM. The OCI images will be simple single-layer modules (like Rust examples), not multi-layer interpreted modules.

Acceptance Criteria

• fabricks build auto-detects and builds Go projects
• fabricks build auto-detects and builds .NET projects
• fabricks run works for Go WASM modules
• fabricks run works for .NET WASM modules
• Example go-hello command module works
• Example go-http HTTP service works (if Go 1.24 reactor support is feasible)
• Example dotnet-hello command module works
• Example dotnet-http HTTP service works
• Documentation updated