Make sure oci config contains handler for wasm or image contains annotation module.wasm.image/variant=compat .
Entrypoint must point to a valid .wat (webassembly text) or .wasm (webassembly binary).
...
"annotations" : {
"run.oci.handler" : " wasm" ... Compile and run wasm modules directly
Following example is using rust to compile a webassembly module but you can use any supported language.
Create a new rust binary using cargo new hello_wasm --bin.
Add relevant function to src/main.rs for this example we will be using a print.
fn main ( ) {
println ! ( "{}" , "This is from a main function from a wasm module" ) ;
}
Compile to wasm32-wasi target using wasm-pack or any other relevant tool. We are going to be using cargo build --target wasm32-wasi
Create relevant image and use your container manager. But for this example we will be running directly using crun and plub config manually.
$ crun run wasm-container
This is from a main function from a wasm module Running OCI wasm compat images with buildah and podman
Compile your .wasm module using instructions from step one.
Prepare a Containerfile with your .wasm module.
FROM scratch
COPY hello.wasm /
CMD ["/hello.wasm" ]
Build wasm image using buildah with annotation module.wasm.image/variant=compat
$ buildah build --annotation " module.wasm.image/variant=compat" .
Make sure your podman points to oci runtime crun build with wasm support.
Run image using podman
$ podman run mywasm-image:latest
This is from a main function from a wasm module