Cherry 😈•6mo ago

Embedding all of deno in Rust?

So, I know that you can use deno_core to roll a javascript runtime in Rust and use that, and use it with your own api and whatnot. But what if you want to be able to leverage already created deno libraries, but in your Rust program? Think of it as a sort of plugin system in your Rust app that can leverage all of deno's api (including packages)

11 Replies

Cherry 😈•6mo ago

I guess, after a bit of reading, what I'm asking for is how to embed the deno runtime (not just the deno_core) into a Rust app, such that regular deno packages should work (if this is even possible)

crowlKats•6mo ago

the deno cli itself does not have a rust crate, and a bunch of functionality (including typescript typechecking, and other aspects) would need to be implemented manually ontop of the deno_runtime crate

Cherry 😈•6mo ago

So far I've partially gotten a runtime working (along with a custom module loader which transpiles as well, and can do network requests; one library example I tested worked verbatim) But when it comes to async await it crashes with

thread 'main' panicked at ~\.cargo\registry\src\index.crates.io-6f17d22bba15001f\deno_unsync-0.3.2\src\task.rs:51:3:
assertion failed: Handle::current().runtime_flavor() == RuntimeFlavor::CurrentThread
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

thread 'main' panicked at ~\.cargo\registry\src\index.crates.io-6f17d22bba15001f\deno_unsync-0.3.2\src\task.rs:51:3:
assertion failed: Handle::current().runtime_flavor() == RuntimeFlavor::CurrentThread
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Any ideas how I could solve this?

crowlKats•6mo ago

hmm not sure. cc @mmastrac since deno_unsync error

mmastrac•6mo ago

@Cherry 🍒 make sure that you are using tokio's current_thread executor -- Deno only supports that particular threading model because of threading limitations in deno_core/v8. Can you share your tokio runtime builder expression?

Cherry 😈•6mo ago

My code is pretty much verbatim from the examples (other than a custom module loader). I'll try out the current thread executor then!

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

mod module_loader;

use std::path::Path;
use std::rc::Rc;

use deno_runtime::deno_core::error::AnyError;
use deno_runtime::deno_core::op2;
use deno_runtime::deno_core::ModuleSpecifier;
use deno_runtime::permissions::PermissionsContainer;
use deno_runtime::worker::MainWorker;
use deno_runtime::worker::WorkerOptions;

deno_runtime::deno_core::extension!(hello_runtime, ops = [op_hello]);

#[op2(fast)]
fn op_hello(#[string] text: &str) {
    println!("Hello {}!", text);
}

#[tokio::main]
async fn main() -> Result<(), AnyError> {
    let client = reqwest::Client::new();

    let js_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("main.js");
    let main_module = ModuleSpecifier::from_file_path(js_path).unwrap();
    let mut worker = MainWorker::bootstrap_from_options(
        main_module.clone(),
        PermissionsContainer::allow_all(),
        WorkerOptions {
            module_loader: Rc::new(module_loader::TypescriptModuleLoader::new(client)),
            extensions: vec![hello_runtime::init_ops()],
            ..Default::default()
        },
    );
    worker.execute_main_module(&main_module).await?;
    worker.run_event_loop(false).await?;
    Ok(())
}

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.

mod module_loader;

use std::path::Path;
use std::rc::Rc;

use deno_runtime::deno_core::error::AnyError;
use deno_runtime::deno_core::op2;
use deno_runtime::deno_core::ModuleSpecifier;
use deno_runtime::permissions::PermissionsContainer;
use deno_runtime::worker::MainWorker;
use deno_runtime::worker::WorkerOptions;

deno_runtime::deno_core::extension!(hello_runtime, ops = [op_hello]);

#[op2(fast)]
fn op_hello(#[string] text: &str) {
    println!("Hello {}!", text);
}

#[tokio::main]
async fn main() -> Result<(), AnyError> {
    let client = reqwest::Client::new();

    let js_path = Path::new(env!("CARGO_MANIFEST_DIR")).join("main.js");
    let main_module = ModuleSpecifier::from_file_path(js_path).unwrap();
    let mut worker = MainWorker::bootstrap_from_options(
        main_module.clone(),
        PermissionsContainer::allow_all(),
        WorkerOptions {
            module_loader: Rc::new(module_loader::TypescriptModuleLoader::new(client)),
            extensions: vec![hello_runtime::init_ops()],
            ..Default::default()
        },
    );
    worker.execute_main_module(&main_module).await?;
    worker.run_event_loop(false).await?;
    Ok(())
}

mmastrac•6mo ago

Interesting. We should add tokio::main to those examples -- you'll need to use this:

#[tokio::main(flavor = "current_thread")]

#[tokio::main(flavor = "current_thread")]

That should Just Work

Cherry 😈•6mo ago

Hey, nice. It worked as you said, thanks a lot!

jeff.hykin•6mo ago

@Cherry 🍒 this is something I tried a while ago but ended up stopping short. if you have a repo with an example setup I'd love to check it out!

Cherry 😈•6mo ago

You can follow the official deno example, but with current_thread runtime https://github.com/denoland/deno/blob/main/runtime/examples/extension_with_ops/main.rs It'll work out of the box

jeff.hykin•6mo ago

Oh cool! Thanks!