fastlike is a Go project that implements the Fastly Compute@Edge ABI using wasmtime and exposes
a http.Handler for you to use.
There's an example proxy implementation in cmd/fastlike which you can run with:
$ go run ./cmd/fastlike -wasm <wasmfile> -backend <proxy address>
You'll need a Fastly Compute@Edge compatible wasm program to run the example proxy. The simplest way to do that is via the fastly cli and using one of the starter kits.
After scaffolding your wasm program using a starter kit and modifying it to your liking, you'll need to build the wasm binary:
$ fastly compute init my-compute-project
# answer the prompts, creating a rust or assemblyscript project
$ fastly compute build
And then use the resulting wasm binary in fastlike:
$ go run ./cmd/fastlike -wasm my-compute-project/bin/main.wasm -backend <proxy address>
You don't need the fastly CLI to build the test program either, as long as you have rust installed and the wasm32-wasi target available:
# This example is using one of the guest implementations of the spec tests
$ cargo target add wasm32-wasi # ensure we have the wasm32-wasi for the current toolchain
# The wasm32-wasi target is configured as the default target via `specs/testdata/rust/.cargo/config`
$ cd specs/testdata/rust; cargo build; cd ../../..
$ go run ./cmd/fastlike -wasm ./specs/testdata/rust/target/wasm32-wasi/debug/example.wasm -backend <proxy address>
However, using the fastly cli will help ensure your toolchains are properly up to date and your dependencies are in-order.
For a more full-featured example, using the default rust starter kit:
# in one terminal:
$ go run ./cmd/fastlike -wasm ./my-compute-project/bin/main.wasm -backend localhost:8000 -bind localhost:5000
# in another
$ python3 -m http.server
# in a third
$ curl localhost:5000/backend
Go, running Rust, calling Go, proxying to Python.