Wasm-in-Wasm with Wasmer

I want to prove that a wasm32-unknown-unknown target can run inside of a wasm32-unknown-unknown target by modifying the wasmer:2.0.0 library.

Requires rust, make and npm.

Directory

alpha/src/  # wasm32-unknown-unknown
└── lib.rs  # wasmer counter example, compiles a string so that module size is greater than 4kb

artifact-registry/src/
├── main.rs  # serves fetch requests from the resources folder
└── resources
    └── # compiled alpha.wasm module lives here

runtime/src/  # wasm32-unknown-unknown
├── fetch.rs  # fetches the alpha wasm32-unknown-unknown from localhost:7878
├── lib.rs  # sets up imports and interacts with the fetched wasm32-unknown-unknown target
└── utils.rs  # log and set_panic macros

How to run

make build  # compiles the alpha, artifact
make artifact-registry-serve  # serves the alpha.wasm file on localhost:7878
make runtime-serve  # compiles a wasm32-unknown-unknown target into an app served on localhost:8080

On localhost:8080 the developer console will have printed some values:

• 1 is the incremented counter from the wasmer example
• [] is the blank results slice returned by the alpha.wasm module - this is a bug because the exported app function should return an integer

You can do this with js-sys but the wasmer import_object wrapping simplifies the management of wasm binary imports.