main.js

import { spawn } from "child_process";
import * as uuid from "uuid";
import WebSocket from 'ws';
import { mkdirSync, existsSync, writeFileSync, readFileSync, copyFileSync } from "fs";
import { rimraf } from "./lib/utils.js";
const config = JSON.parse(readFileSync('./resources/config.json', 'utf8'));
// at every restart we clear the simulations directory
rimraf(config.simulation_folder);
mkdirSync(config.simulation_folder);
//store the ox-view connection
var clients = new Array();
//Setup the SocketServer
var wss = new WebSocket.Server({ port: config.serverPort, host: config.serverIP });
console.log(`server listening on port ${config.serverPort}`);
wss.on('connection', (connection) => {
    let settings;
    var top_file, dat_file;
    var oxDNA;
    // we need to know client index to remove them on 'close' event
    var index = clients.push(connection) - 1;
    console.log(`processes connected: ${clients.length}`);
    if (index >= config.allowed_connections) {
        console.log("refused connection");
        connection.close();
        return;
    } // limit connection numbers
    var user_id = uuid.v1();
    //create a work directory per connection
    let dir = `${config.simulation_folder}/${user_id}`;
    if (!existsSync(dir)) {
        mkdirSync(dir);
    }
    connection.on('message', (message) => {
        if (message === "abort") {
            //handle simulation stop
            if (oxDNA)
                oxDNA.kill();
            return;
        }
        //if relax is running kill it regardless of the message
        if (oxDNA)
            oxDNA.kill();
        //parse incomming congiguration
        var data = JSON.parse(message);
        let useDNA = true;
        top_file = data.top_file;
        dat_file = data.dat_file;
        //inject oxDNA configuration settings
        settings = data.settings;
        Object.assign(settings, config.default_oxDNA_settings);
        console.log(settings["interaction_type"]);
        if (settings["interaction_type"].includes("DNA")) {
            useDNA = true;
            settings["seq_dep_file_DNA"] = "oxDNA2_sequence_dependent_parameters.txt";
        }
        else if (settings["interaction_type"].includes("RNA")) {
            settings["seq_dep_file_RNA"] = "rna_sequence_dependent_parameters.txt";
            useDNA = false;
        }
        if ("trap_file" in data) {
            settings["external_forces"] = "1";
            settings["external_forces_file"] = "trap.txt";
            //write forces file
            writeFileSync(`${dir}/trap.txt`, data.trap_file);
        }
        if ("par_file" in data) {
            settings["parfile"] = "par_file.par";
            //write par file (for anm)
            writeFileSync(`${dir}/par_file.par`, data.par_file);
        }
        //construct input file from transmitted settings
        let input_file = [];
        for (let [key, value] of Object.entries(settings)) {
            input_file.push(`${key} = ${value}`);
        }
        //write topology and configuration into dedicated connection folder
        writeFileSync(`${dir}/conf_file.dat`, dat_file);
        writeFileSync(`${dir}/last_conf.dat`, dat_file);
        writeFileSync(`${dir}/top_file.top`, top_file);
        //write input and base parameter files
        writeFileSync(`${dir}/${config.input_file}`, input_file.join('\n'));
        if (useDNA) {
            copyFileSync(`./resources/oxDNA2_sequence_dependent_parameters.txt`, `${dir}/oxDNA2_sequence_dependent_parameters.txt`);
        }
        else {
            copyFileSync(`./resources/rna_sequence_dependent_parameters.txt`, `${dir}/rna_sequence_dependent_parameters.txt`);
        }
        // perform simulation @ cwd = current working dir
        oxDNA = spawn(config.oxDNA, [`${config.input_file}`], { cwd: dir });
        console.log(`connection ${index}\t|\trelax\t|\t started`);
        // the trick is to have energy and conf file print settings to be the same
        if (oxDNA.stdout) {
            oxDNA.stdout.on('data', (data) => {
                console.log(`stdout: ${data}`);
                // than we can transfer data easily
                if (existsSync(`${dir}/last_conf.dat`)) {
                    connection.send(JSON.stringify({
                        dat_file: readFileSync(`${dir}/last_conf.dat`, 'utf8'),
                        console_log: data.toString()
                    }));
                }
            });
        }
        if (oxDNA.stderr) {
            oxDNA.stderr.on('data', (data) => {
                console.error(`stderr: ${data}`);
            });
        }
        oxDNA.on('close', (code) => {
            console.log(`connection ${index}\t|\trelax\t|\tfinished\t|\tcode: ${code}`);
            if (existsSync(`${dir}/last_conf.dat`)) {
                connection.send(JSON.stringify({
                    dat_file: readFileSync(`${dir}/last_conf.dat`, 'utf8'),
                    console_log: data.toString()
                }));
            }
        });
    });
    // user disconnected
    connection.on('close', (code) => {
        // remove user from the list of connected clients
        clients.splice(index, 1);
        if (oxDNA) {
            //stop process just make sure no writing occures
            oxDNA.kill();
            //TODO: make somehow async or policy speciffic
            rimraf(dir);
            console.log(`client ${index} id disconnected\t|\tcode: ${code}`);
            console.log(`removed assosiated working dir:`);
            console.log(dir);
            console.log(`processes connected: ${clients.length}`);
        }
    });
});