move

Ownership and borrowing references

Please install the prerequisites first!

Code

The src/main.rs source code shows

• When the hello string variable is passed into the take() function, it is no longer available outside of take().
• You can create a clone() of the hello string variable to pass to take(). This way, the original hello is still available outside of take().
• You can also pass a reference of the hello string to the borrow() function. Since the borrow() function only borrowed a reference of this variable, the original hello is still available outside of borrow().
  • The &string reference can be automatically cast to an immutable &str. So, the borrow() function can also take a &str as argument.
• If the hello string is mutable and the passed reference is also mutable, you can make changes to the string through its reference inside the borrow_mut() function and the hello string outside of the function will be changed too. That is the "side effect" of pass-by-reference.

Step by step guide

Compile the Rust source code project to a Wasm bytecode file.

$ cargo build --target wasm32-wasi --release

Run the Wasm bytecode file in WasmEdge CLI.

$ wasmedge target/wasm32-wasi/release/move.wasm

Build and publish on Docker

The Dockerfile follows the above steps to build and package a lightweight OCI-compliant container image for the Wasm app. Now, we need to publish the container image to Docker Hub. You just need to specify that the WasmEdge application image is for the wasi/wasm platform.

$ docker buildx build --provenance=false --platform wasi/wasm -t secondstate/rust-example-move .
... ...
$ docker push secondstate/rust-example-move

Then, with Docker Desktop and Wasm support enabled, you can run it.

$ docker run --rm --runtime=io.containerd.wasmedge.v1 --platform=wasi/wasm secondstate/rust-example-move:latest