Resolver API

[XmiliaH]

Add resolver API allowing to share resolvers for multiple NodeVM instances.

A new resolver can be created with makeResolverFromLegacyOptions.

const resolver = makeResolverFromLegacyOptions({
    external: true,
    builtin: ['fs', 'path'],
    root: './',
    mock: {
        fs: {
            readFileSync: () => 'Nice try!'
        }
    }
});
const vm = new NodeVM({
    console: 'inherit',
    sandbox: {},
    require: resolver
});

[theinterned]

Thank you for putting this together, I was able to try it out for our use case and compare it to the optmizaiotn you suggested in https://github.com/patriksimek/vm2/issues/514#issuecomment-1496607700.

I used hey to test our service with the various implementations.

Version 1

The actual code we have is a bit more involved, but roughly this is the current implementation we have with your optimization from #514

let _resolver: Resolver

const script = new VMScript(`module.exports = require('./bundle.js');`);

function render(args) {
  const vm = createVM();
  const handler = vm.run(script);
  return handler(args);
}

function createVM() {
  const vm = new NodeVM({ require: { external: true, root: './'} })
  cacheResolver(vm)
  return vm
}

function cacheResolver(vm: NodeVM) {
  if (!_resolver) {
     _resolver = vm._resolver
  } else if (vm._resolver) {
    try {
      Object.assign(vm._resolver, {
        packageCache: _resolver.packageCache,
        scriptCache: _resolver.scriptCache,
      })
    } catch (error) {
      report(error)
      throw error
    }
  }
}

Results

0.1122 secs / request @ p50 for 100 requests with concurrency 1

``` Summary: Total: 11.8491 secs Slowest: 0.3310 secs Fastest: 0.1013 secs Average: 0.1185 secs Requests/sec: 8.4395 Total data: 1849100 bytes Size/request: 18491 bytes Response time histogram: 0.101 [1] | 0.124 [82] |■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ 0.147 [12] |■■■■■■ 0.170 [2] |■ 0.193 [1] | 0.216 [1] | 0.239 [0] | 0.262 [0] | 0.285 [0] | 0.308 [0] | 0.331 [1] | Latency distribution: 10% in 0.1053 secs 25% in 0.1083 secs 50% in 0.1122 secs 75% in 0.1196 secs 90% in 0.1305 secs 95% in 0.1619 secs 99% in 0.3310 secs Details (average, fastest, slowest): DNS+dialup: 0.0000 secs, 0.1013 secs, 0.3310 secs DNS-lookup: 0.0000 secs, 0.0000 secs, 0.0011 secs req write: 0.0000 secs, 0.0000 secs, 0.0001 secs resp wait: 0.1183 secs, 0.1011 secs, 0.3309 secs resp read: 0.0001 secs, 0.0000 secs, 0.0002 secs Status code distribution: [200] 100 responses ```

Version 2

Again, this cuts out some details, but this is roughly what my implementation of this makeResolverFromLegacyOptions API looks like

let _resolver: Resolver

const script = new VMScript(`module.exports = require('./bundle.js');`);

function render(args) {
  const vm = createVM();
  const handler = vm.run(script);
  return handler(args);
}

function createVM() {
  const resolver = getResolver()
  const vm = new NodeVM({ require: resolver })
  return vm
}

function getResolver() {
  if(_resolver) return _resolver

  _resolver = makeResolverFromLegacyOptions({ external: true, root: './'})
  return _resolver
}

Results

0.1167 secs / request @ p50 for 100 requests with concurrency 1

``` Summary: Total: 12.2841 secs Slowest: 0.3012 secs Fastest: 0.1069 secs Average: 0.1228 secs Requests/sec: 8.1406 Total data: 1849100 bytes Size/request: 18491 bytes Response time histogram: 0.107 [1] | 0.126 [82] |■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ 0.146 [10] |■■■■■ 0.165 [2] |■ 0.185 [2] |■ 0.204 [1] | 0.223 [0] | 0.243 [1] | 0.262 [0] | 0.282 [0] | 0.301 [1] | Latency distribution: 10% in 0.1095 secs 25% in 0.1123 secs 50% in 0.1167 secs 75% in 0.1224 secs 90% in 0.1363 secs 95% in 0.1694 secs 99% in 0.3012 secs Details (average, fastest, slowest): DNS+dialup: 0.0000 secs, 0.1069 secs, 0.3012 secs DNS-lookup: 0.0000 secs, 0.0000 secs, 0.0010 secs req write: 0.0000 secs, 0.0000 secs, 0.0001 secs resp wait: 0.1227 secs, 0.1067 secs, 0.3009 secs resp read: 0.0001 secs, 0.0000 secs, 0.0002 secs Status code distribution: [200] 100 responses ```

Conclusion

The API you propose here gives me the same run-time characteristics, and a nicer API 👍

I'd say it's a winner 🏆

[XmiliaH]

Thanks for the feedback

[theinterned]

Oh and for comparison, if I don't cache the resolver at all, I eventually start to error if I try to make 100 consecutive requests, but at 19 requests I see the following

Results

1.7231 secs / request @ p50 for 19 requests with concurrency 1

``` Summary: Total: 31.3897 secs Slowest: 1.8185 secs Fastest: 0.1819 secs Average: 1.6521 secs Requests/sec: 0.6053 Total data: 351329 bytes Size/request: 18491 bytes Response time histogram: 0.182 [1] |■■ 0.346 [0] | 0.509 [0] | 0.673 [0] | 0.837 [0] | 1.000 [0] | 1.164 [0] | 1.328 [0] | 1.491 [0] | 1.655 [1] |■■ 1.818 [17] |■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■■ Latency distribution: 10% in 1.6816 secs 25% in 1.7151 secs 50% in 1.7231 secs 75% in 1.7926 secs 90% in 1.8185 secs 0% in 0.0000 secs 0% in 0.0000 secs Details (average, fastest, slowest): DNS+dialup: 0.0001 secs, 0.1819 secs, 1.8185 secs DNS-lookup: 0.0001 secs, 0.0000 secs, 0.0010 secs req write: 0.0000 secs, 0.0000 secs, 0.0001 secs resp wait: 1.6519 secs, 0.1803 secs, 1.8184 secs resp read: 0.0001 secs, 0.0000 secs, 0.0002 secs Status code distribution: [200] 19 responses ```

So you can see that caching the resolver is a huge improvement for us!