srap/bin/run

#!/usr/bin/env node

"use strict";

// FIXME: Safe shutdown on ctrl+C
// FIXME: Somehow automatically detect whether other kernels are running on the system, and automatically clear locks when that is not the case?

const Promise = require("bluebird");
const yargs = require("yargs");
const path = require("path");
const express = require("express");

const createKernel = require("../src/kernel");

let argv = yargs.argv;
let configurationPath = argv._[0];
let listenHost = argv.listenHost ?? "127.0.0.1";
let listenPort = argv.listenPort ?? 3131;

let absoluteConfigurationPath = path.join(process.cwd(), configurationPath);
let configuration = require(absoluteConfigurationPath);

return Promise.try(() => {
	return createKernel(configuration);
}).then((kernel) => {
	kernel.run();

	let metricsApp = express();

	metricsApp.get("/metrics", (req, res) => {
		return Promise.try(() => {
			return kernel.getMetrics();
		}).then(({ contentType, metrics }) => {
			res.set("Content-Type", contentType);
			res.send(metrics);
		});
	});

	metricsApp.listen({ host: listenHost, port: listenPort }, () => {
		console.log(`Metrics server listening on port ${listenPort}, host ${listenHost}`);
	});
});