Does graalvm help us?

[thekalinga]

I just came across graalvm & wanted to check whether graalvm can make our life simpler & improve performance when doing pre-rendering?

http://www.graalvm.org/

Thanks

[swaechter]

Hey. Indeed GraalVM looks like a really interesting alternative (Although it's a separate JVM) I used this code for testing:

server.ts:

import {RenderAdapter} from "./renderadapter";

const {AppServerModuleNgFactory, LAZY_MODULE_MAP} = require("./../dist-server/main.bundle");

var renderAdapter = new RenderAdapter(AppServerModuleNgFactory, LAZY_MODULE_MAP, "<app-root></app-root>");
renderAdapter.renderPage("uuid1", "/");
renderAdapter.renderPage("uuid2", "/home");
renderAdapter.renderPage("uuid3", "/keywords");
renderAdapter.renderPage("uuid4", "/about");

renderadapter.ts:

require("zone.js/dist/zone-node");

import {provideModuleMap} from "@nguniversal/module-map-ngfactory-loader";
import {renderModuleFactory} from "@angular/platform-server";

export declare function registerRenderAdapter(renderadapter: RenderAdapter): void;

export declare function receiveRenderedPage(uuid: string, html: string, error: any): void;

export class RenderAdapter {

    constructor(private appservermodulengfactory: any, private lazymodulemap: any, private html: string) {
        //registerRenderAdapter(this);
    }

    setHtml(html: string) {
        this.html = html;
    }

    renderPage(uuid: string, uri: string) {
        renderModuleFactory(this.appservermodulengfactory, {
            document: this.html,
            url: uri,
            extraProviders: [
                provideModuleMap(this.lazymodulemap)
            ]
        }).then(html => {
            console.log(uuid + ": " + html);
            //receiveRenderedPage(uuid, html, null);
        });
    }
}

I am able to render these requests with the node binary provided by GraalVM (I guess they just deploy a copy of Node with some Graal related changes)

Launching the server.js from Java like seen here does not work. I get an error message that require is undefined or the Node modules can't be found.

At the moment I am not sure if I have to rebuild Graal.js or if it is not supported at all. I will open an issue for this in the GraalVM project.

[thekalinga]

Thanks. Please link that issue here

[swaechter]

@thekalinga I just posted my question: oracle/graaljs#2

[divyakumarjain]

@swaechter Seems like https://github.com/graalvm/examples/blob/master/weather_predictor/weatherServer.js javascript in https://github.com/graalvm/examples uses "require".

Did some additional research and seems like nodejs "require" aka module is available when application is started as nodejs application. When Java application triggers Javascript it does not have nodejs feature but can only trigger Javascript interpreter which does not have nodejs capabilities.

[swaechter]

@divyakumarjain Yeah, I also saw the example.

Did some additional research and seems like nodejs "require" aka module is available when application is started as nodejs application. When Java application triggers Javascript it does not have nodejs feature but can only trigger Javascript interpreter which does not have nodejs capabilities.

Yes, that's true. As Christian pointed out in the GraalVM issue, it's a lot easier to implement a custom JS engine into Node.js than Node.js capabilities into Java.

For now I am going to close this issue, because it's also quite a burden to use a custom JVM. I am looking for a really cool draft in #23