1 //! Example of instantiating a wasm module which uses WASI preview1 imports
2 //! implemented through the async preview2 WASI implementation.
3 
4 /*
5 You can execute this example with:
6     cmake examples/
7     cargo run --example wasip2-async
8 */
9 
10 use wasmtime::component::{Component, Linker, ResourceTable};
11 use wasmtime::*;
12 use wasmtime_wasi::p2::bindings::Command;
13 use wasmtime_wasi::{WasiCtx, WasiCtxView, WasiView};
14 
15 pub struct ComponentRunStates {
16     // These two are required basically as a standard way to enable the impl of IoView and
17     // WasiView.
18     // impl of WasiView is required by [`wasmtime_wasi::p2::add_to_linker_sync`]
19     pub wasi_ctx: WasiCtx,
20     pub resource_table: ResourceTable,
21     // You can add other custom host states if needed
22 }
23 
24 impl WasiView for ComponentRunStates {
25     fn ctx(&mut self) -> WasiCtxView<'_> {
26         WasiCtxView {
27             ctx: &mut self.wasi_ctx,
28             table: &mut self.resource_table,
29         }
30     }
31 }
32 
33 #[tokio::main]
34 async fn main() -> Result<()> {
35     let engine = Engine::default();
36     let mut linker = Linker::new(&engine);
37     wasmtime_wasi::p2::add_to_linker_async(&mut linker)?;
38 
39     // Create a WASI context and put it in a Store; all instances in the store
40     // share this context. `WasiCtx` provides a number of ways to
41     // configure what the target program will have access to.
42     let wasi = WasiCtx::builder().inherit_stdio().inherit_args().build();
43     let state = ComponentRunStates {
44         wasi_ctx: wasi,
45         resource_table: ResourceTable::new(),
46     };
47     let mut store = Store::new(&engine, state);
48 
49     // Instantiate our component with the imports we've created, and run it.
50     let component = Component::from_file(&engine, "target/wasm32-wasip2/debug/wasi.wasm")?;
51     let command = Command::instantiate_async(&mut store, &component, &linker).await?;
52     let program_result = command.wasi_cli_run().call_run(&mut store).await?;
53     match program_result {
54         Ok(()) => Ok(()),
55         Err(()) => std::process::exit(1),
56     }
57 }
58