golem-wasm-rpc

Defines data types for Golem's remote function invocation and conversions between them.

• WitValue is the WIT-defined generic data type capable of representing an arbitrary value, generated by wit-bindgen
• A builder and an extractor API for WitValue
• Value is a recursive Rust type which is more convenient to work with than WitValue. Conversion between WitValue and Value is implemented in both directions.
• Protobuf message types for describing values and types, and a protobuf version of WitValue itself and conversion from and to Value and WitValue
• JSON representation of WIT values, as defined in the Golem docs.
• Conversion of Value to and from wasmtime values

The JSON representation requires additional type information which can be extracted using the golem-wasm-ast crate.

Host and stub mode

The golem-wasm-rpc crate can be both used in host and guest environments:

To compile the host version:

cargo build -p golem-wasm-rpc --no-default-features --features host

To compile the guest version, has minimal dependencies and feature set to be used in generated stubs:

cargo component build -p golem-wasm-rpc --no-default-features --features stub

Feature flags

• arbitrary adds an Arbitrary instance for Value
• bincode adds Bincode codecs for some types
• host-bindings enables WIT-generated types for wasmtime hosts
• json adds conversion functions for mapping of a WIT value and type definition to/from JSON
• poem_openapi adds poem OpenAPI type class instances for some of the types
• protobuf adds the protobuf message types
• serde adds serde JSON serialization for some of the types
• text enables wasm-wave based text representation for values
• wasmtime adds conversion to wasmtime Val values
• host enables all features: arbitrary, bincode, host-bindings, json, poem_openapi, protobuf, serde, text, typeinfo, and wasmtime
• stub is to be used in generated WASM stubs and disables all features, and generates guest bindings instead of host bindings