Add a component model example

This adds the 'Hello World' example from here[0]. The runtime is in Rust
and the component is in C.

This requires some new tools

  - https://github.com/bytecodealliance/wit-bindgen
  - https://github.com/bytecodealliance/wasm-tools

You can use the pre-built packages, once downloaded and untar'd, edit

  rust/hello_world/component/Makefile

and adjust the paths for the above tools.

To build the component with make you may need to specify where the WASI
sysroot is

  $ make WASI_SYSROOT=/path/to/wasi-sysroot

[0]: <https://docs.rs/wasmtime/latest/wasmtime/component/macro.bindgen.html>

Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/rust/hello_world/wit/my-component.wit b/rust/hello_world/wit/my-component.wit
new file mode 100644
index 0000000..5ce6b6f
--- /dev/null
+++ b/rust/hello_world/wit/my-component.wit
@@ -0,0 +1,8 @@
+// wit/my-component.wit
+
+package my:project;
+
+world hello-world {
+    import name: func() -> string;
+    export greet: func();
+}