You can add wasmtime to your list of dependencies in mix.exs:
def deps do
[
{:wasmtime, "~> 0.3.0"}
]
endIn this example, the Wasm module is compiled, instantiated and a host function is called and imported from Elixir:
mod = ~S/
(module
(import "" "" (func $compute (param i32) (result i32)))
(func (export "run") (param i32) (result i32) (call $compute (local.get 0)))
)
/
{:ok, pid} =
Wasmtime.load(%Wasmtime.FromBytes{
bytes: mod,
func_imports: [
{fn x ->
"Hello from Elixir! Got #{x}. Returning an i32 value" |> IO.inspect()
20 + x
end, [:i32], [:i32]}
]
})
{:ok, [200]} = Wasmtime.call_func(pid, "run", [180])This next example loads a Wasm module from this rust lib.rs file that's been built with wasm-pack:
{:ok, pid} = Wasmtime.load(%Wasmtime.FromFile{file_path: "test/data/wasmapp/wasmapp_bg.wasm"})
{:ok, {[:i32, :i32], [:i32]}} = Wasmtime.get_func(pid, "add")
{:ok, {[:i32], [:i32]}} = Wasmtime.get_func(pid, "plus_10")
{:ok, {[:i32, :i32], [:i32]}} = Wasmtime.get_func(pid, "min")
{:ok, [20]} = Wasmtime.call_func(pid, "add", [11, 9])
{:ok, [30]} = Wasmtime.call_func(pid, "plus_10", [20])
{:ok, [-10]} = Wasmtime.call_func(pid, "min", [-10, 3])
If you want to see more usage examples, check this test file out.
- Functions are supported with the four value types
i32,i64,f32andf64 - Memory will be supported soon
- Globals and Tables will be considered in the future
Wasmtime is fast. Here's a benchmark with these simple functions, running on my computer, for a reference:
Compiling NIF crate :wasmtime_ex (native/wasmtime_ex)...
Finished release [optimized] target(s) in 0.07s
Operating System: Linux
CPU Information: Intel(R) Core(TM) i7-4720HQ CPU @ 2.60GHz
Number of Available Cores: 8
Available memory: 31.25 GB
Elixir 1.11.0
Erlang 23.1.1
Benchmark suite executing with the following configuration:
warmup: 20 s
time: 1 min
memory time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 6.67 min
Name ips average deviation median 99th %
add_xt 140.22 K 7.13 μs ±461.08% 6.94 μs 11.20 μs
plus_10_xt 134.72 K 7.42 μs ±443.67% 7.21 μs 11.29 μs
add 21.75 K 45.98 μs ±52.83% 42.90 μs 83.64 μs
plus_10 19.78 K 50.55 μs ±47.20% 46.26 μs 91.51 μs
imports 4.28 K 233.76 μs ±20.80% 230.13 μs 332.01 μs