PM2 unable to run ESM packages: ERR_UNSUPPORTED_ESM_URL_SCHEME

[ox-harris]

What's going wrong?

In this version of pm2 (v4.4.1), pm2.start ('reference/to/esm-package/script.js') is throwing the following error in err.log file: Error [ERR_UNSUPPORTED_ESM_URL_SCHEME]: Only file and data URLs are supported by the default ESM loader

The stack trace reveals the problem to be with the ESM script loader in lib\ProcessContainerFork.js:29:24. There the import statement is attempting to import the ESM script using the file path instead of a file scheme.

How could we reproduce this issue?

Try starting a script within an ES module package: pm2.start ('reference/to/esm-package/script.js'), then find the error in the err file for the process.

Supporting information

PM2 version: v4.4.1
Node version: v13.7.0
OS: windows

I wouldn't mind submitting a PR for a fix. It simply requires converting the given path to a file URL using url.pathToFileURL().
So, instead of import(process.env.pm_exec_path);, we should now have import(url.pathToFileURL(process.env.pm_exec_path));

[Unitech]

published in pm2@4.5.0

npm install pm2@latest -g

[ParallelUniv3rse]

Hi @ox-harris,
still having trouble with this when running basic pm2 start ecosystem.json on windows in cluster mode.
I've tried switching to fork mode, but no luck there either. Process is still using ProcessContainer.js where this same exact issue occurs on line 301.

Any special steps on how to make use of this fix?

EDIT: Nevermind, fork mode works, that was just me reading the logs wrong, but the problem in ProcessContainer.js:301 still stands - cluster mode does not work.

[pubmikeb]

@Unitech, unfortunately this issue is still relevant for pm2 v.5.1.0 running on Node.js 16.4.0.
Currently, I can't use "exec_mode": "cluster", only "exec_mode": "fork" can be used.

Please, fix the incompatibility to be able use the full potential of pm2.

[aramis-it]

Same problem with cluster mode v5.1.0 Node 16.5 Windows 10
Are there any solutions?

[rujiel]

I was experiencing this error being thrown from another file, ProcessContainer.js, but my workaround was to look for the usage of "process.env.pm_exec_path" that it is choking on in the pm2 library files, and it replace it with the string path to your script. It will auto-append your drive letter, so just start the path with a slash. i.e.

import(process.env.pm_exec_path);
-->
import('/Users/you/script.mjs');

Just be sure to remember to revert the pm2 change you've made! Or that could get confusing real fast.