Missing node.js support from context library

[anthonyskipper]

We need the ability to call a node.js function from inside the jvm context library. It would be best if this could be called repeatedly. It is completely ok if Node is orphaned from the greater event loop and has no signal access.

[wirthi]

Hi Anthony,

can you please clarify what you mean with "a Node.js function". Do you mean an npm module, or Node.js core functionality ("fs.js")?

If it is plain JavaScript code with no dependency on Node.js, you can likely load it with load(filename) already.

Best,
Christian

[thiagogcm]

Hi @wirthi
I am able to run plain javascript using the polyglot api on OpenJDK 11 by including the maven dependencies on my project, just like demonstrated here: https://github.com/graalvm/graal-js-jdk11-maven-demo
Is it possible to rely on npm packages as well?

[wirthi]

Hi @thiagogcm

When you start from JVM and not from the node binary, you get a JavaScript engine, not the full Node.js ecosystem.

node and npm are binary applications that expect to be started by themselves, standalone. We can cheat in a JVM into those applications (that's what we do in GraalVM), but once you have started a full JVM you cannot inject a node application in the same process. You'd need to start node's eventloop then, ensure it gets access to all the signals it requires, etc. That might be possible, but is outside our current focus.

What you can try, however, is to load npm modules. As long as they contain only JavaScript code and do not try to access core Node.js functionality, that should work. Tools like browserify can help you with that.

Best,
Christian

[eliasvasylenko]

It's worth noting that while there is no official support for it from Node.js other applications have successfully embedded node, i.e. so that it can be used as a shared-library without being the entry-point of the application. The obvious example is Electron, but much smaller projects have also managed it such as discussed here and here.

I understand that it is outside the focus of the project itself atm, but if someone were to come along who wanted to do this I assume it would be possible to link against node via JNI or whatever and achieve the same effect for Graal.js.

[eliasvasylenko]

This issue is a duplicate of #2

[ralleman]

I found this library https://github.com/apigee/trireme. I'm going to start porting pieces of it under trial (I need net and http initially). Unless someone has a better idea.

[chumer]

You might also be interested in:
https://github.com/mikehearn/nodejvm
https://blog.plan99.net/vertical-architecture-734495f129c4

[ralleman]

Thanks @chumer. I don't think Mike's wrapper will work in my case because I'm running trusted and untrusted code together. The nodejvm wrapper appears to be creating a full-access NodeJS thread first under which everything is run.

[ralleman]

I spent the day working through the trireme code and can now see how to port it. Problem is that it's very old (Node version v0.10 - current version is v12) and the differences between these Node versions is quite significant. Porting it isn't a one-man show I think for this reason.

[psanders]

I had this issue before with Nashorn, and endup using Nodyn's package loader. I created a repo with an example of my approach. You can also see this working in a larger project.

I hope this helps someone!

[wirthi]

Hi,

Since GraalVM 20.0.0, we have experimental support for common.js require().

Best,
Christian