2145855954
* Add example of execution limits using fuel consumption * run rustfmt * Use a more naive WAT implementation * Catch error and return cleanly * Add a C example to demonstrate fuel consumption * Add error handling for add_fuel
34 lines
1.1 KiB
Rust
34 lines
1.1 KiB
Rust
//! Example of limiting a WebAssembly function's runtime using "fuel consumption".
|
|
|
|
// You can execute this example with `cargo run --example fuel`
|
|
|
|
use anyhow::Result;
|
|
use wasmtime::*;
|
|
|
|
fn main() -> Result<()> {
|
|
let mut config = Config::new();
|
|
config.consume_fuel(true);
|
|
let engine = Engine::new(&config)?;
|
|
let store = Store::new(&engine);
|
|
store.add_fuel(10_000)?;
|
|
let module = Module::from_file(store.engine(), "examples/fuel.wat")?;
|
|
let instance = Instance::new(&store, &module, &[])?;
|
|
|
|
// Invoke `fibonacci` export with higher and higher numbers until we exhaust our fuel.
|
|
let fibonacci = instance.get_typed_func::<i32, i32>("fibonacci")?;
|
|
for n in 1.. {
|
|
let fuel_before = store.fuel_consumed().unwrap();
|
|
let output = match fibonacci.call(n) {
|
|
Ok(v) => v,
|
|
Err(_) => {
|
|
println!("Exhausted fuel computing fib({})", n);
|
|
break;
|
|
}
|
|
};
|
|
let fuel_consumed = store.fuel_consumed().unwrap() - fuel_before;
|
|
println!("fib({}) = {} [consumed {} fuel]", n, output, fuel_consumed);
|
|
store.add_fuel(fuel_consumed)?;
|
|
}
|
|
Ok(())
|
|
}
|