Add a Rust Crate Dependency

Important constraints

• The compilation target is wasm32-wasip2 — only crates that support this target will work.
• Crates that use threads, native system calls, mmap, networking via std::net, or platform-specific C libraries will not compile.
• Pure Rust crates and crates that support wasm32-wasi generally work.
• If unsure whether a crate compiles for WASM, add it and run golem build to find out.

Steps

1. Add the dependency to Cargo.toml

   In the component’s Cargo.toml (not a workspace Cargo.toml), add the crate under [dependencies]:

   [dependencies]
   my-crate = "1.0"

   If the project has a Cargo workspace with [workspace.dependencies], add the version there and reference it with my-crate = { workspace = true } in the component crate.

2. Build to verify

   golem build

   Do NOT run cargo build directly — always use golem build.

3. If the build fails

   • Check the error for unsupported target or missing C dependencies — these crates are incompatible with wasm32-wasip1.
   • Try enabling a wasm or wasi feature flag if the crate provides one.
   • Look for an alternative crate that supports WASM.

Already available crates

These crates are already in the project’s Cargo.toml — do NOT add them again:

• golem-rust — Golem agent framework, durability, transactions
• wstd — WASI standard library (HTTP client, async I/O)
• log — logging
• serde / serde_json — serialization

HTTP and networking

Use wstd::http for HTTP requests. The standard std::net module is not available on WASM.

AI / LLM features

To add AI capabilities, add the relevant golem-ai-* provider crate (e.g., golem-ai-llm-openai) and configure the provider in the component’s golem.yaml dependencies section.