systemquery/src/lib/agent/Agent.mjs

"use strict";

import fs from 'fs';
import os from 'os';
import path from 'path';

import log from '../io/NamespacedLog.mjs'; const l = log("agent");

import settings from '../../settings.mjs';

import PeerServer from './PeerServer.mjs';
import parse_peer_name from '../parse/peer_name.mjs';
import hostuuid from '../io/hostuuid.mjs';

class Agent {
	constructor(config) {
		this.config = config;
	}
	
	async find_secret() {
		if(this.config.secret_join_filepath !== "CHANGE_ME") {
			let filepath = path.resolve(
				path.dirname(settings.cli.config),
				this.config.secret_join_filepath
			);
			if(fs.existsSync(filepath))
				return await fs.promises.readFile(filepath, "utf-8");
		}
		
		if(this.config.secret_join !== "CHANGE_ME")
			return this.config.secret_join;
		
		throw new Error(`Error: Failed to find join secret.`);
	}
	
	async init() {
		///
		// 1: Create our local environment
		///
		/** Our peer id - calculated automatically from the system's uuid */
		this.peer_id = await hostuuid(this.config.net.port);
		this.peer_name = os.hostname();
		
		
		///
		// 2: Create the peer server
		///
		this.server = new PeerServer(
			this.peer_id,
			await this.find_secret()
		);
		this.server.retries = this.config.net.peer_retries;
		
		
		///
		// 3: Attach message handling listeners
		///
		this.server.on("message-peerlist-request", this.__send_peer_list.bind(this));
		this.server.on("message-peerlist-response", this.__handle_peer_list.bind(this));
		
		
		///
		// 4: Start listening
		///
		l.log(`Starting peer listener....`);
		await this.server.listen(
			this.config.net.port,
			this.config.net.bind_address
		);
		l.log(`Listening on ${this.config.net.bind_address}:${this.config.net.port}`);
		
		
		///
		// 5: Add initial peers to kick things off
		///
		await this.server.add_peers(...this.config.peers.map(
			peer => parse_peer_name(peer)
		));
		
		l.log(`Added ${this.server.peers().length} / ${this.config.peers.length} initial peers`);
		if(this.config.peers.length < 1)
			l.warn(`No initial peers were specified! It's recommended that you specify at least 1 on every host.`);
		
		// Ask for more peers
		await this.server.broadcast("peerlist-request", {});
	}
	
	/**
	 * Sends a list of known peers to the given peer.
 	 * @param	{Peer}		peer	The peer to send the list to.
	 * @return	{Promise}	A Promise that resolves whent he message has been sent.
	 */
	async __send_peer_list(peer, _msg) {
		l.log(`Sending peer list to ${peer.id_short}`);
		await peer.send("peerlist-response", {
			peers: this.server.peers()
		});
	}
	
	async __handle_peer_list(peer, msg) {
		l.log(`Received peer list from ${peer.id_short}`);
		if(!(msg.peers instanceof Array)) {
			l.warn(`Encountered invalid peer list message from peer ${peer.id_short}.`);
			return false;
		}
		let peerids_connected = this.server.peers().map(el => el.id);
		let new_peers = await this.server.add_peers(...msg.peers
				.filter(el => !peerids_connected.includes(el.id) && el.id !== this.peer_id)
				.map(el => { return { address: el.listening_address, port: el.listening_port }; }));
		if(new_peers.length > 0)
			l.log(`Connected to ${new_peers.length} / ${msg.peers.length} peers from peerlist sent by ${peer.id_short}`);
		else
			l.log(`No new peers in peerlist sent by ${peer.id_short}`);
	}
}

export default Agent;