cli.js

#!/usr/bin/env node

import {parseArgs} from 'node:util'
import {PREFIX as NATS_CLIENT_NAME_PREFIX} from './lib/nats.js'

// todo: use import assertions once they're supported by Node.js & ESLint
// https://github.com/tc39/proposal-import-assertions
import {createRequire} from 'node:module'
const require = createRequire(import.meta.url)
const pkg = require('./package.json')

const {
	values: flags,
} = parseArgs({
	options: {
		'help': {
			type: 'boolean',
			short: 'h',
		},
		'version': {
			type: 'boolean',
			short: 'v',
		},
		'port': {
			type: 'string',
			short: 'p',
		},
		'nats-servers': {
			type: 'string',
		},
		'nats-user': {
			type: 'string',
		},
		'nats-client-name': {
			type: 'string',
		},
		'nats-consumer-name': {
			type: 'string',
		},
		't0': {
			type: 'string',
		},
	},
	allowPositionals: true,
})

if (flags.help) {
	process.stdout.write(`
Usage:
    serve-gtfs-rt-from-nats [options]
Options:
	--port                    -p  Port to serve the GTFS Realtime feed on.
	                              Default: $PORT, otherwise 3000
	--nats-servers                NATS server(s) to connect to.
	                              Default: $NATS_SERVERS
	--nats-user                   User to use when authenticating with NATS server.
	                              Default: $NATS_USER
	--nats-client-name            Name identifying the NATS client among others.
	                              Default: ${NATS_CLIENT_NAME_PREFIX}\${randomHex(4)}
	--nats-consumer-name          Name of the NATS JetStream consumer on the
	                              GTFS_RT_2 stream.
	                              Default: $GTFS_RT_CONSUMER_NAME, otherwise \`nats-
	                              consuming-gtfs-rt-server\`
	--diff-entities-ttl           Time to keep DIFFERENTIAL-mode GTFS-RT FeedEntities
	                              in the combined FULL_DATASET-mode feed for, in seconds.
	                              Default: 10 minutes
	--t0                          UNIX timestamp to use as now, for debugging purposes.
	                              Default: current UNIX timestamp
Examples:
    serve-gtfs-rt-from-nats --port 1234 --nats-user foo
\n`)
	process.exit(0)
}

if (flags.version) {
	process.stdout.write(`${pkg.name} v${pkg.version}\n`)
	process.exit(0)
}

import {serveGtfsRtDataFromNats} from './index.js'
import {withSoftExit} from './lib/soft-exit.js'

const cfg = {}
const opt = {
	natsOpts: {},
}

if ('port' in flags) {
	cfg.port = parseInt(flags.port)
} else if ('PORT' in process.env) {
	cfg.port = parseInt(process.env.PORT)
} else {
	cfg.port = 3000
}

if ('nats-servers' in flags) {
	opt.natsOpts.servers = flags['nats-servers'].split(',')
}
if ('nats-user' in flags) {
	opt.natsOpts.user = flags['nats-user']
}
if ('nats-client-name' in flags) {
	opt.natsOpts.name = flags['nats-client-name']
}

if ('t0' in flags) {
	opt.t0 = parseInt(flags.t0)
}

if ('diff-entities-ttl' in flags) {
	opt.differentialEntitiesTtl = parseInt(flags['diff-entities-ttl'])
}

const {
	stop,
} = await serveGtfsRtDataFromNats(cfg, opt)

withSoftExit(stop)