engine.js

/*
 * engine.js
 *
 * Defines the Engine object, which is the top level application singleton that represents this running engine instance.
 *
 * The engine object is primarily defined by its start() method, which defines most of the startup configuration
 * activities for the engine.
 */
var restify = require("restify");
var util = require("./util");
var events = require("events");
var async = require("async");
var process = require("process");
var machine = require("./machine");
var config = require("./config");
var OS = process.platform;
var PLATFORM = process.env.PLATFORM;
var log = require("./log").logger("engine");
//developer adjust next:, comment, un-comment as needed to track startup at deepest level
// ... also see enginge_config.js, last section, for another set point that can create a log level at start
//require("./log").setGlobalLevel("g2");
var db = require("./db");
var macros = require("./macros");
var dashboard = require("./dashboard");
var network = require("./network");
var glob = require("glob");
var argv = require("minimist")(process.argv);
var fs = require("fs");
var sessions = require("client-sessions");
var authentication = require("./authentication");
var profiles = require("./profiles");
var crypto = require("crypto");
var moment = require("moment");
//other util
var Util = require("util");
var configWatcher = require("./config_watcher"); // Import the config_watcher module

var PACKAGE_CHECK_DELAY = 30; // Seconds

// The engine object has a few high level properties and some key methods that define the application lifecycle
// Most of the important stuff is in the start() method.
var Engine = function () {
    this.version = null;
    this.time_synced = false;
    this.firmware = {
        build: null,
        config: null,
        version: null,
    };
    // is istavailable to the client via HTTP endpoint and websocket
    this.status = {
        online: false,
    };

    // The default network manager is the generic one (until the network module has been asked to load one specific to this platform)
    this.networkManager = network.Generic;
    //TO-DO file should not be emiting (bring these into seperate modules)
    events.EventEmitter.call(this);
};

Util.inherits(Engine, events.EventEmitter);

/*
 * Configure the engine for the first time.
 * This function is typically called when an engine configuration does not exist.
 * It sets some defaults in the engine config (by way of the config module) based on system platform.
 * Mainly this amounts to configuring appropriate serial port paths and http hosting ports
 * for different types of machines.
 */
function EngineConfigFirstTime(callback) {
    if (PLATFORM) {
        log.info("Setting platform to " + PLATFORM);
        config.engine.set("platform", PLATFORM);
    }

    switch (OS) {
        case "linux":
            var ports = {
                control_port_linux: "/dev/fabmo_g2_motion",
                data_port_linux: "/dev/ttyfabmo_g2_motion",
                // control_port_linux: "/dev/ttyACM0",
                // data_port_linux: "/dev/ttyACM0",
            };
            config.engine.update(ports, function () {
                callback();
            });
            break;
        case "darwin":
            config.engine.set("server_port", 9876);
            glob.glob("/dev/cu.usbmodem*", function (err, files) {
                if (files.length >= 1) {
                    var ports = {
                        control_port_osx: files[0],
                        data_port_osx: files[1] || files[0],
                    };
                    config.engine.update(ports, function () {
                        callback();
                    });
                } else {
                    callback();
                }
            });
            break;

        default:
            callback();
            break;
    }
}

/*
 * Set the current system time to the provided value.
 * obj - an object with a 'utc' property that coresponds to the current UTC time
 */
Engine.prototype.setTime = function (time) {
    if (this.time_synced) {
        log.warn("Not accepting an externally provided time.  Local time is trusted.");
        return;
    } else {
        var m = moment.unix(time / 1000.0);
        var t = m.utc().format("YYYY-MM-DD HH:mm:ss");
        var cmd = "timedatectl set-time " + t + "; timedatectl";
        util.doshell(cmd, function (stdout) {
            log.debug("Time Set To:  " + stdout);
            this.time_synced = true;
        });
    }
};

/*
 * Stop this engine instance.
 * Basically does cleanup activities before shutting the engine down.
 */
Engine.prototype.stop = function (reason, callback) {
    this.machine.disconnect(reason);
    this.machine.setState(this.machine, "stopped");
    callback(null);
};

/*
 * Get the version of this engine.
 * Honor semver numbering:
 * For working dev version tag in branch from most recent; use ODD numbers just for redundancy
 * For production builds, tag with the next EVEN number in MASTER.
 * The Release Version is codified by a version.json that defines a version object that includes:
 *     hash - A hash for the build, typically a commit SHA (may not exist in a release type build)
 *     number - The semver version number
 *     type - The type of release, either 'dev', 'rc', or 'release'
 *
 * If that file exists and can be parsed, return a version object that reflects its contents.
 * If it does not exist, use git (if available on the system) to read out working version information instead
 * (See: example-version.json)
 */
Engine.prototype.getVersion = function (callback) {
    // grab the version and abbreviated SHA (if one)
    util.doshell(
        "git describe",
        function (data) {
            this.version = {};
            this.version.number = (data || "").trim();

            // Our version tags in git are prefixed with "v",
            // The rrequirement is to display without the "v"
            // We have old versions without the "v" prefix
            if (this.version.number.substring(0, 1) === "v") {
                this.version.number = this.version.number.substring(1);
            }

            this.version.debug = "debug" in argv;
            // then see if we have an official release version# in json file
            // see: version-example.json
            fs.readFile(
                "version.json",
                "utf8",
                function (err, data) {
                    if (err) {
                        log.debug(" ... no version file ... using git and dev info");
                        this.version.type = "dev";
                        this.version.number = this.version.number + "-dev";
                        var random = Math.floor(Math.random() * (99999 - 10000)) + 10000;
                        log.info("Adding random prefix to dev engine version");
                        this.version.number = random.toString() + "-" + this.version.number;
                        return callback(null, this.version);
                    }
                    try {
                        log.debug(" ... found json version file ... this is a RELEASE VERSION");
                        data = JSON.parse(data);
                        if (data.number) {
                            this.version.number = data.number;
                            this.version.type = "release";
                        }
                    } catch (e) {
                        log.debug(" ... can't parse version file!");
                        this.version.number = this.version.number + "-dev-fault";
                        this.version.type = "dev";
                        // eslint-disable-next-line no-redeclare
                        var random = Math.floor(Math.random() * (99999 - 10000)) + 10000;
                        log.info("Adding random prefix to dev engine version");
                        this.version.number = random.toString() + "-" + this.version.number;
                    } finally {
                        callback(null, this.version);
                    }
                }.bind(this)
            );
        }.bind(this)
    );
};

/*
 * Return "info" about this engine, which currently is just version data for the engine and the firmware
 */
Engine.prototype.getInfo = function (callback) {
    callback(null, {
        firmware: this.firmware,
        version: this.version,
    });
};

// Set the online flag (indicates whether the engine is online) to the provided value
//   online - true to indicate that the engine can see the network.  False otherwise.
Engine.prototype.setOnline = function (online) {
    this.status.online = online;
    this.emit("status", this.status);
};

// ##############################################################################
/*
 * This function is the primary content of the Engine object.  It is called on application launch, and is
 * sort of the "main thread" of execution.  It executes a bunch of startup/configuration functions, and
 * then sets up the http server to listen on the appropriate port.  Setup happens first so the user doesn't
 * connect to the engine before it is ready to accept connections.
 */
Engine.prototype.start = function (callback) {
    async.series(
        [
            // AFTER LOADING SOME Config data and info
            // We will:
            //    Configure the engine data directories
            //    Create the folder structure (typically) in /opt/fabmo
            //    ... eg: /opt/fabmo/config, /opt/fabmo/macros, etc...

            // TODO - This seems like a duplication of the same step below
            ////## BUT testing shows that for some start scenarios,
            //     ... both versions seem necessary 1/2/21

            function setup_application(callback) {
                log.info("#START# --> Checking engine data directory tree...");
                config.createDataDirectories(callback);
            },

            // Load the engine configuration from disk.
            function load_engine_config(callback) {
                log.info("Loading engine configuration...");
                config.configureEngine(callback);
            },

            // Determine if we're configuring the engine for the first time ever.
            // If so, populate the engine configuration with defaults that are sensible for this platform.
            function check_engine_config(callback) {
                if (!config.engine.get("init")) {
                    log.info("Configuring the engine for the first time...");
                    EngineConfigFirstTime(function () {
                        config.engine.set("init", true);
                        callback();
                    });
                } else {
                    callback();
                }
            },

            // Load profiles.  See the profiles module for what this entails.
            function load_profiles(callback) {
                // eslint-disable-next-line no-unused-vars
                profiles.load(function (err, profiles) {
                    if (err) {
                        log.error(err);
                    }
                    callback();
                });
            },

            // Load users.  See config/user_config.js for what this entails.
            function load_users(callback) {
                log.info("Loading users....");
                config.configureUser(function () {
                    callback();
                });
            },

            // Read the selected profile from the engine config.
            // If the engine config doesn't specify a profile, look in /fabmo/site/.default
            // If /fabmo/site/.default exists and has content, interpret its content as the selected profile.
            // If neither of these strategies yields a profile, just choose the 'Default' profile.
            function profile_shim(callback) {
                var profile = config.engine.get("profile");
                var def = "";
                if (profile) {
                    return callback();
                } else {
                    fs.readFile("../site/.default", "utf8", function (err, content) {
                        if (err) {
                            def = "default";
                        } else {
                            def = content;
                        }
                        config.engine.set("profile", def, callback);
                    });
                }
            }.bind(this),

            // Read the engine version and hang onto it
            function get_fabmo_version(callback) {
                log.info("Getting engine version...");
                this.getVersion(
                    function (err, data) {
                        if (err) {
                            log.error(err);
                            this.version = "";
                            return callback();
                        }
                        log.info("Got engine version: " + JSON.stringify(this.version));
                        this.version = data;
                        callback();
                    }.bind(this)
                );
            }.bind(this),

            // The approot should be cleared if:
            //   - We're running in 'debug' mode (and might be making changes to system apps)
            //   - The version of the engine has changed since the last time we run it.
            // So, we check those things, and clear the approot accordingly.
            // See dashboard/app_manager.js for more about the approot.
            function clear_approot(callback) {
                var flg_clr_approot = false;
                var last_time_version = (config.engine.get("version") || "").trim();
                var this_time_version = (this.version.hash || this.version.number || "").trim();
                log.debug("Previous engine version: " + last_time_version);
                log.debug(" Current engine version: " + this_time_version);
                if (last_time_version != this_time_version) {
                    log.info("Engine version has changed - flag to clear the approot.");
                    flg_clr_approot = true;
                } else {
                    log.info("Engine version is unchanged since last run.");
                    //callback();
                }
                if ("debug" in argv) {
                    log.info("Running in debug mode - flag to clear the approot.");
                    flg_clr_approot = true;
                }
                if (flg_clr_approot) {
                    config.clearAppRoot(function (err, stdout) {
                        log.info("Clearing the approot ...");
                        config.engine.set("version", this_time_version);
                        if (err) {
                            log.error(err);
                        } else {
                            log.debug("   @flg_cr_approot- " + stdout);
                        }
                        callback();
                    });
                } else {
                    callback();
                }
            }.bind(this),

            function create_data_directories(callback) {
                log.debug("Create_data_directories ...");
                config.createDataDirectories(callback);
            }.bind(this),

            // "Apply" the engine configuration, that is, take the configuration values loaded and actually
            // set up the application based on them. See config/engine_config.js to see what this entails.
            function apply_engine_config(callback) {
                log.info("Applying engine configuration...");
                config.engine.apply(callback);
            },

            // Configure the DB see db.js to see what this entails.
            function setup_database(callback) {
                log.info("Configuring database...");
                db.configureDB(callback);
            },

            // Cleanup the DB.  This is to clear jobs that may be "dangling" after a crash, or other inconsistencies.
            // See db.js for more details.
            function clean_database(callback) {
                log.info("Cleaning up database...");
                db.cleanup(callback);
            },

            // Connect to G2 and initialize machine runtimes.  See machine.js for what this entails.
            function connect(callback) {
                log.info("Connecting to G2...");
                // eslint-disable-next-line no-unused-vars
                machine.connect(function (err, machine) {
                    if (err) {
                        log.error("!!!!!!!!!!!!!!!!!!!!!!!!");
                        log.error("Could not connect to G2.");
                        log.error("(" + err + ")");
                        log.error("!!!!!!!!!!!!!!!!!!!!!!!!");
                    }
                    callback(null);
                });
            }.bind(this),

            // Apply the "machine" configuration - see config/machine_config.js for details
            function load_machine_config(callback) {
                this.machine = machine.machine;
                log.info("Loading the machine configuration...");
                // eslint-disable-next-line no-unused-vars
                config.configureMachine(this.machine, function (err, result) {
                    if (err) {
                        log.warn(err);
                    }
                    callback(null);
                });
            }.bind(this),

            // The default unit system is specified in the machine configuration.  It requires
            // special care to apply - see g2.js for details.
            function set_units(callback) {
                if (this.machine.isConnected()) {
                    this.machine.driver.setUnits(config.machine.get("units"), callback);
                } else {
                    callback(null);
                }
            }.bind(this),

            // Configure G2 by loading all its json settings and static configuration parameters
            function load_driver_config(callback) {
                if (this.machine.isConnected()) {
                    log.info("Configuring G2...");
                    config.configureDriver(
                        machine.machine.driver,
                        // eslint-disable-next-line no-unused-vars
                        function (err, data) {
                            if (err) {
                                log.error("There were problems loading the G2 configuration.");
                            }
                            callback(null);
                        }
                    );
                } else {
                    log.warn("Skipping G2 configuration due to no connection.");
                    // eslint-disable-next-line no-unused-vars
                    config.configureDriver(null, function (err, data) {
                        callback(null);
                    });
                    callback(null);
                }
            }.bind(this),

            // Retrieve the firmware version from G2.  This is done only once, and the value
            // is cached as a property of the Engine object.
            function get_g2_version(callback) {
                if (this.machine.isConnected()) {
                    log.info("Getting G2 firmware version...");
                    this.machine.driver.get(
                        ["fb", "fbs", "fbc"],
                        function (err, value) {
                            if (err) {
                                log.error("Could not get the G2 firmware build. (" + err + ")");
                            } else {
                                log.info("G2 Firmware Information: " + value);
                                this.firmware.build = value[0];
                                this.firmware.version = value[1];
                                this.firmware.config = value[2];

                                // Our version tags in git are prefixed with "v",
                                // The rrequirement is to display without the "v"
                                // We have old versions without the "v" prefix
                                if (this.firmware.version.substring(0, 1) === "v") {
                                    this.firmware.version = this.firmware.version.substring(1);
                                }
                            }
                            callback(null);
                        }.bind(this)
                    );
                } else {
                    log.warn("Skipping G2 firmware version check due to no connection.");
                    callback(null);
                }
            }.bind(this),

            // This is a shim that clears some obsolete entries from the configuration that have been
            // known to cause errors with modern versions of G2.
            // TODO - this is the sort of thing that might be better done by the updater as part of the
            //        installation process.  It is typical for such processes to "migrate" config files to latest version.
            function g2_shim(callback) {
                log.debug("Running G2 Shim...");
                var entries = [
                    "1sa",
                    "1tr",
                    "1mi",
                    "2sa",
                    "2tr",
                    "2mi",
                    "3sa",
                    "3tr",
                    "3mi",
                    "4sa",
                    "4tr",
                    "4mi",
                    "5sa",
                    "5tr",
                    "5mi",
                    "6sa",
                    "6tr",
                    "6mi",
                    "ja",
                ];
                var do_shim = false;
                for (var i = 0; i < entries.length; i++) {
                    if (config.driver.has(entries[i])) {
                        do_shim = true;
                    }
                }
                if (do_shim) {
                    log.debug("Deleting obsolete entries in G2 config");
                    // eslint-disable-next-line no-unused-vars
                    config.driver.deleteMany(entries, function (err, data) {
                        config.driver.restore(function () {
                            callback();
                        });
                    });
                } else {
                    log.debug("No obsolete entries in G2 config.");
                    callback();
                }
            }.bind(this),

            // Load commands which are populated dynamically from the contents of a folder
            // in the openSBP runtime.  See runtime/opensbp/opensbp.js for what this entails.
            function load_opensbp_commands(callback) {
                if (!this.machine.isConnected()) {
                    log.warn("Not loading SBP Commands due to no connection to motion system.");
                    return callback(null);
                }
                log.info("Loading OpenSBP Commands...");
                this.machine.sbp_runtime.loadCommands(callback);
            }.bind(this),

            // Apply the OpenSBP runtime config.  See config/opensbp_config.js for what this entails.
            function load_opensbp_config(callback) {
                if (!this.machine.isConnected()) {
                    log.warn("Not configuring SBP due to no connection to motion system.");
                    return callback(null);
                }
                log.info("Configuring OpenSBP runtime...");
                config.configureOpenSBP(callback);
            }.bind(this),

            // Apply the machine config.  See config/machine_config.js for what this entails
            function apply_machine_config(callback) {
                log.info("Applying machine configuration...");
                config.machine.apply(callback);
            }.bind(this),

            // Setup the dashboard.  See dashboard/index.js and dashboard/app_manager.js for what this entails.
            function configure_dashboard(callback) {
                log.info("Configuring dashboard...");
                dashboard.configure(callback);
            },

            // Load the apps, see dashboard/app_manager.js for what this entails.
            function load_apps(callback) {
                log.info("Loading dashboard apps...");
                dashboard.loadApps(function (err, result) {
                    callback(null, result);
                });
            },

            // Load macros from disk.  See macros.js
            function load_macros(callback) {
                log.info("Loading macros...");
                macros.load(callback);
            },

            // Load and apply the 'instance' configuration.  This is the dynamic machine state, like the current position,
            // which is saved periodically in order to preserve state if the tool is power cycled.
            // See config/instance_config.js for more details.
            function load_instance_config(callback) {
                if (!this.machine.isConnected()) {
                    log.warn("Not configuring instance due to no connection to motion system.");
                    return callback(null);
                }
                log.info("Loading instance info...");
                config.configureInstance(this.machine.driver, callback);
            }.bind(this),

            function apply_instance_config(callback) {
                if (!this.machine.isConnected()) {
                    log.warn("Not applying instance config due to no connection to motion system.");
                    return callback(null);
                }
                log.info("Applying instance configuration...");
                config.instance.apply(callback);
            }.bind(this),

            // The secret key is used for authentication.  It is persistent, stored with other config files.
            function generate_auth_key(callback) {
                log.info("Configuring secret key...");
                var secret_file = config.getDataDir() + "/config/auth_secret";
                fs.readFile(
                    secret_file,
                    "utf8",
                    function (err, data) {
                        // If there's already a secret key from disk, use it
                        if (!err && data && data.length == 512) {
                            log.info("Secret key already exists, using that.");
                            this.auth_secret = data;
                            return callback();
                        }

                        // If not, generate, save and use a new one
                        log.info("Generating a new secret key.");
                        this.auth_secret = crypto.randomBytes(256).toString("hex");
                        fs.writeFile(
                            secret_file,
                            this.auth_secret,
                            // eslint-disable-next-line no-unused-vars
                            function (err, data) {
                                callback();
                            }.bind(this)
                        );
                    }.bind(this)
                );
            }.bind(this),

            // Initialize the network module
            function setup_network(callback) {
                var name = config.engine.get("name");
                log.info("name is - " + name);
                network.createNetworkManager(
                    name,
                    // eslint-disable-next-line no-unused-vars
                    function (err, nm) {
                        this.networkManager = nm;
                        this.networkManager.on(
                            "network",
                            function (evt) {
                                if (evt.mode === "station" || evt.mode === "ethernet") {
                                    // 30 Second delay is used here to make sure timesyncd has enough time to update network time
                                    // before trying to pull an update (https requests will fail with an inaccurate system time)
                                    log.info(
                                        "Network is possibly available:  Going to check for packages in " +
                                            PACKAGE_CHECK_DELAY +
                                            " seconds."
                                    );
                                    setTimeout(
                                        function () {
                                            // log.info('Running package check due to network change');
                                            // this.runAllPackageChecks();
                                        }.bind(this),
                                        PACKAGE_CHECK_DELAY * 1000
                                    );
                                }
                            }.bind(this)
                        );

                        // Call the network manager init function, which actually starts looking for networks, etc.
                        log.info("Setting up the network...");
                        try {
                            this.networkManager.init();
                            log.info("Network manager started.");
                        } catch (e) {
                            log.error(e);
                            log.error("Problem starting network manager:" + e);
                        }
                        return callback(null);
                    }.bind(this)
                );
            }.bind(this),

            // Start the accessories (spindle speed controller, etc.)
            function add_accessories(callback) {
                this.machine.startAccessories(callback);
                callback();
            }.bind(this),

            // Start the USB-drive manager to track whether there is a USB drive inserted;
            // ... presence or absence will be used to set the search location for job file loading.
            function start_usb_drive_manager(callback) {
                log.info("Starting USB drive manager...");
                try {
                    this.machine.startUSBDriveManager();
                    log.info("USB drive manager started.");
                    return callback(null);
                } catch (e) {
                    log.error("Exception while starting USB drive manager: " + e.message);
                    log.error(e.stack);
                    return callback(null); // Proceed with startup despite the exception
                }
            }.bind(this),

            // Kick off the server if all of the above went OK.
            function start_server(callback) {
                log.info("Setting up the webserver...");

                // Initialize a server and attach it to the application
                var server = restify.createServer({ name: "FabMo Engine" });
                this.server = server;

                // Allow JSON over Cross-origin resource sharing
                log.info("Configuring cross-origin requests...");
                server.use(function crossOrigin(req, res, next) {
                    res.header("Access-Control-Allow-Origin", "*");
                    res.header("Access-Control-Allow-Headers", "X-Requested-With");
                    return next();
                });

                // Introduce deliberate latency for testing.  You can activate this by
                // passing the --slow switch when running server.js (must include --debug too)
                ////## 7/20/23th Had trouble getting this to trigger in scripted start
                ////## Not sure how useful it is in anycase
                if ("debug" in argv && argv.debug === "slow") {
                    // not working this way for current vscode scripting
                    log.warn("Configuring deliberate LATENCY FOR TESTING ...");
                    server.use(function latency(req, res, next) {
                        setTimeout(next, 500 * Math.random());
                    });
                } else {
                    log.info("NORMAL EXEC ! Not configuring deliberate latency.");
                }

                // If in 'debug' mode, do some extra logging of HTTP requests
                if ("debug" in argv) {
                    server.use(function debug(req, res, next) {
                        // temporarily removed because making hard to read manual mode action
                        // log.debug(req.method + ' ' + req.url);
                        next();
                    });
                }

                // The query parser does just that - map query params to an object for convenience
                server.use(
                    restify.plugins.queryParser({
                        mapParams: true,
                    })
                );

                /*
                 * The engine URL scheme includes a software version number that performs a
                 * cache-busting function:  When the engine is updated, the version number in the
                 * URL is revised, and the cache is thus busted.
                 * 404 errors are handled in two different ways depending on their content:
                 */
                server.on("NotFound", function (req, res) {
                    var current_hash = config.engine.get("version");
                    var url_arr = req.url.split("/");
                    // If a URL contains a hash that doesn't match the current version hash:
                    // Replace the URL's hash with the current one, and redirect.
                    if (url_arr[1] !== current_hash) {
                        url_arr.splice(1, 1, current_hash);
                        var newPath = url_arr.join("/");
                        res.redirect(newPath, function () {
                            return;
                        });
                    } else {
                        // If the URL contains a current hash, and simply points to a bogus resource,
                        // just redirect to the root.
                        res.redirect("/", function () {
                            return;
                        });
                    }
                });

                // Catch-all handler that responds gracefully when an internal server error occurs.
                server.on("uncaughtException", function (res, err) {
                    log.uncaught(err);
                    var answer = {
                        status: "error",
                        message: err.message,
                    };
                    res.json(answer);
                });

                // Configure local directory for uploading files
                log.info("Cofiguring upload directory...");
                server.use(
                    restify.plugins.bodyParser({
                        uploadDir: config.engine.get("upload_dir") || "/tmp",
                        mapParams: true,
                    })
                );

                // TODO: What is this path sanitizer doing?
                server.pre(restify.pre.sanitizePath());

                // Configure authentication
                log.info("Configuring authentication...");
                log.info("Secret Key: " + this.auth_secret.slice(0, 5) + "..." + this.auth_secret.slice(-5));
                server.cookieSecret = this.auth_secret;
                server.use(
                    sessions({
                        // cookie name dictates the key name added to the request object
                        cookieName: "session",
                        // should be a large unguessable string
                        secret: server.cookieSecret, // REQUIRE HTTPS SUPPORT !!!
                        // how long the session will stay valid in ms
                        duration: 31 * 24 * 60 * 60 * 1000,
                        cookie: {
                            maxAge: 31 * 24 * 60 * 60 * 1000, // duration of the cookie in milliseconds, defaults to duration above
                            ephemeral: false,
                            httpOnly: false, // when true, cookie is not accessible from javascript
                            secure: false, // when true, cookie will only be sent over SSL. use key 'secureProxy' instead if you handle SSL not in your node process
                        },
                    })
                );
                server.use(authentication.passport.initialize());
                server.use(authentication.passport.session());

                // gzipping is a typical way to speed up network operations
                // We enable it on the server, so that supporting clients can use it
                log.info("Enabling gzip for transport...");
                server.use(restify.plugins.gzipResponse());

                // Import the routes module and apply the routes to the server
                // Routes are loaded dynamically. See routes/routes.js for details.
                log.info("Loading routes...");

                server.io = require("socket.io")(server.server);
                // eslint says routes is unused, but removing it breaks fabmo
                // eslint-disable-next-line no-unused-vars
                var routes = require("./routes")(server);
                // Kick off the server listening for connections
                // 0.0.0.0 causes us to listen on ALL interfaces (so the engine can be seen over ethernet, wifi, etc.)
                server.listen(config.engine.get("server_port"), "0.0.0.0", function () {
                    log.info(server.name + " listening at " + server.url);
                    callback(null, server);
                });

                // TODO - should this be done after server.listen, or before? (or does it matter?)
                authentication.configure();
            }.bind(this),

            // Copy backup at the start of the session and then start the watcher
            function copy_backup_and_start_watcher(callback) {
                log.debug("Copying backup and starting watcher...");
                // Copy backup at the start of the session
                configWatcher.copyBackupAtStart((err) => {
                    if (err) {
                        return callback(err);
                    }
                    configWatcher.startWatcher();
                    callback();
                });
            },
        ],

        // Print some kind of sane debugging information if anything above fails
        // eslint-disable-next-line no-unused-vars
        function (err, results) {
            if (err) {
                log.stack();
                log.error(err);
                typeof callback === "function" && callback(err);
            } else {
                typeof callback === "function" && callback(null, this);
            }
        }.bind(this)
    );
};

// This module IS the engine object, but instantiating the object does virtually nothing:
// It is the call to start() that kicks off all the real work of running the application.
module.exports = new Engine();