Under the hood

Vision

Bundle the best tools in a structured environment to provide a stable and fast-paced development experience.

Modules

henri is a set of modules booted in eight run levels. Modules on the same level start concurrently; the next level starts when they are all done.

Level	Modules
0	configuration, logger, module registry
1	GraphQL, mail
2	controllers, HTTP server (Express)
3	models, views
4	users (sessions, passport, roles)
5	routes, workers
6	last stage (your own modules)
7	tests

Reloadable modules are torn down in reverse order and started again in order when a file changes, so a saved model reloads models, views, routes and workers but leaves the HTTP server alone.

Writing a module

A module extends BaseModule, has a unique name and a runlevel, and implements init(). Reloadable modules add reload(); modules holding resources add stop().

const BaseModule = require('@usehenri/core/src/base/module');

class Metrics extends BaseModule {
  constructor() {
    super();
    this.name = 'metrics';
    this.runlevel = 6;
    this.reloadable = false;
  }

  async init() {
    this.henri.server.app.get('/_metrics', (req, res) =>
      res.json({ ok: true })
    );
    return this.name;
  }

  async stop() {
    return false;
  }
}

module.exports = Metrics;

The instance is exposed as henri.<name>, which is why names must be unique: registering two modules with the same name, or one whose name collides with an existing property of henri, stops the boot with a duplicate module error.

Contributing

henri is a pnpm monorepo. Clone usehenri/henri, run pnpm install at the root, pnpm test to run the suites and pnpm lint before sending a pull request. The disk adapter tests download a MongoDB binary on first run.