server.ts

const primaryProcInfo = { name: '#', deployedAt: new Date(), pid: process.pid }
await import('reflect-metadata')
const { promises:{readFile, writeFile} } = await import('fs')
const { default: cluster } = await import('cluster')
const { default: os } = await import('os')
await import('dotenv/config')
const { logger } = await import('./src/utils/logger.js')
if (cluster.isPrimary) logger.procInfo = primaryProcInfo
if (cluster.isWorker) {
	const forkList = JSON.parse(await readFile('.app-init.json', 'utf8'))
	logger.procInfo = forkList.find(f => f.pid === process.pid)
}
const { expand, isDevEnv, genUniqTimestamp } = await import('./src/utils/basic.js')
const { sendDevMail } = await import('./src/utils/mail.js')

// Catch all errors, and send to DevMail.
// - unhandled errors
// - unhandled unawaited promise rejections
process.on('uncaughtException', error => sendDevMail(error))
process.on('unhandledRejection', (reason, promise) => sendDevMail({ reason, promise }))

if (cluster.isPrimary) {
	// eslint-disable-next-line no-var
	var forkList: any = []

	const cpus = isDevEnv()? 1: os.cpus().length
	logger.app(`Deploying ${cpus} forks.`)
	for (let i = 0; i < cpus; i++) {
		const worker = cluster.fork()
		addForkRecord(worker.process.pid)
	}
	await writeFile(`.app-init.json`, JSON.stringify(forkList))

	cluster.on('online', worker => {
		const { pid } = worker.process
		logger.app(`Fork ${pid} is online.`)
	})
	cluster.on('exit', (worker, c, s) => {
		const pid = worker.process.pid
		logger.app(`Fork ${pid} exited. Code: ${c}. Signal: ${s}. Deploying new fork.`)
		cluster.fork()
	})
}

if (cluster.isWorker) {
	// Each is a fork
	const {
		env: { APP_PORT },
	} = process

	const { app } = await import('./app.js')
	const port = APP_PORT || 3000
	app.listen(port, () => logger.app(`Listening at PORT ${port}.`))
}

/**
 * Stores app instance information,
 * and assigns single alphabet names.
 */
function addForkRecord (pid) {
	//const {forkList} = app.locals
	const _forkData = { pid, deployedAt: new Date() }

	if (!forkList.length) {
		const forkData = { name: 'A', ..._forkData }
		forkList.push(forkData)
		return
	}

	const forkNames: any[] = forkList.map(fork => fork.name)
	const lastNameCodepoint = forkNames[forkNames.length - 1].codePointAt(0)
	const nextName = String.fromCodePoint(lastNameCodepoint + 1)
	const forkData = { name: nextName, ..._forkData }
	forkList.push(forkData)
}

export {}