Sockets: Go rewrite

Work in progress. I haven't written documentation for the Go code or
confirmed whether this works as intended on Windows yet.

This turned into a pretty substantial refactor of the Node version of
sockets-related code to not only to make using Go child processes
possible, but to optimize it and make unit testing of it and any code
dependent on it possible to write entirely synchronously. sockets.js
and sockets-workers.js are now written in Typescript, though they won't
be able to be transpiled until after Config, Users, Dnsbl, and Monitor
work with it as well.

Fixes #2943

package.json

@@ -48,15 +48,13 @@
   "license": "MIT",
   "devDependencies": {
     "@types/cloud-env": "^0.2.0",
-    "@types/node": "^8.0.1",
+    "@types/node": "^8.0.28",
     "@types/node-static": "^0.7.0",
     "@types/nodemailer": "^1.3.33",
     "@types/ofe": "^0.5.0",
     "@types/sockjs": "^0.3.31",
     "eslint": "^4.0.0",
     "mocha": "^3.0.0",
-    "@types/node": "^8.0.1",
-    "@types/nodemailer": "^1.3.33",
     "typescript": "^2.5.0-dev.20170622"
   }
 }

sockets-workers.js

@@ -13,6 +13,8 @@
 'use strict';
 
 const cluster = require('cluster');
+const fs = require('fs');
+const path = require('path');
 
 // IPC command tokens
 const EVAL = '$';
@@ -461,7 +463,46 @@ if (cluster.isWorker) {
 	});
 
 	let app = require('http').createServer();
-	let appssl = Config.ssl ? require('https').createServer(Config.ssl.options) : null;
+	/** @type {?NodeJS.Server} */
+	let appssl = null;
+	if (Config.ssl) {
+		let key;
+		try {
+			key = path.resolve(__dirname, Config.ssl.options.key);
+			if (!fs.lstatSync(key).isFile()) throw new Error();
+			try {
+				key = fs.readFileSync(key);
+			} catch (e) {
+				require('./crashlogger')(new Error(`Failed to read the configured SSL private key PEM file:\n${e.stack}`), `Socket process ${cluster.worker.id} (${process.pid})`, true);
+			}
+		} catch (e) {
+			console.warn('SSL private key config values will not support HTTPS server option values in the future. Please set it to use the absolute path of its PEM file.');
+			key = Config.ssl.options.key;
+		}
+
+		let cert;
+		try {
+			cert = path.resolve(__dirname, Config.ssl.options.cert);
+			if (!fs.lstatSync(cert).isFile()) throw new Error();
+			try {
+				cert = fs.readFileSync(cert);
+			} catch (e) {
+				require('./crashlogger')(new Error(`Failed to read the configured SSL certificate PEM file:\n${e.stack}`), `Socket process ${cluster.worker.id} (${process.pid})`, true);
+			}
+		} catch (e) {
+			console.warn('SSL certificate config values will not support HTTPS server option values in the future. Please set it to use the absolute path of its PEM file.');
+			cert = Config.ssl.options.cert;
+		}
+
+		if (key && cert) {
+			try {
+				// In case there are additional SSL config settings besides the key and cert...
+				appssl = require('https').createServer(Object.assign({}, Config.ssl.options, {key, cert}));
+			} catch (e) {
+				require('./crashlogger')(new Error(`The SSL settings are misconfigured:\n${e.stack}`), `Socket process ${cluster.worker.id} (${process.pid})`, true);
+			}
+		}
+	}
 
 	const StaticServer = require('node-static').Server;
 	const roomidRegex = /^\/[A-Za-z0-9][A-Za-z0-9-]*\/?$/;
@@ -529,6 +570,7 @@ if (cluster.isWorker) {
 	process.once('disconnect', () => {
 		multiplexer.destroy();
 		app.close();
+		/** @type {?NodeJS.Server} */
 		if (appssl) appssl.close();
 	});
 

sockets.js

@@ -301,8 +301,6 @@ class GoWorker extends EventEmitter {
 		/** @type {boolean | void} */
 		this.exitedAfterDisconnect = undefined;
 
-		/** @type {string[]} */
-		this.obuf = [];
 		/** @type {string} */
 		this.ibuf = '';
 		/** @type {?Error} */
@@ -351,17 +349,7 @@ class GoWorker extends EventEmitter {
 	 * @return {boolean}
 	 */
 	send(message) {
-		if (!this.isConnected()) {
-			this.obuf.push(message);
-			return false;
-		}
-
-		if (this.obuf.length) {
-			this.obuf.splice(0).forEach(msg => {
-				this.connection.write(JSON.stringify(msg) + DELIM);
-			});
-		}
-
+		if (!this.isConnected()) return false;
 		return this.connection.write(JSON.stringify(message) + DELIM);
 	}
 
@@ -380,7 +368,7 @@ class GoWorker extends EventEmitter {
 	 * @return {boolean}
 	 */
 	isDead() {
-		return this.connection && !this.connection.destroyed;
+		return this.process && (this.process.exitCode !== null || this.process.statusCode !== null);
 	}
 
 	/**
@@ -419,6 +407,7 @@ class GoWorker extends EventEmitter {
 					// if it crashed.
 					if (this.error) throw this.error;
 				}
+
 				this.emit('exit', this, ...args);
 			});
 		});
@@ -441,16 +430,16 @@ class GoWorker extends EventEmitter {
 		this.connection.on('data', /** @param {string} data */ data => {
 			let idx = data.lastIndexOf(DELIM);
 			if (idx < 0) {
-				// Very long message...
 				this.ibuf += data;
 				return;
 			}
 
-			// Because of how Node handles TCP connections, we can
-			// receive any number of messages, and they may not
-			// be guaranteed to be complete.
-			let messages = this.ibuf;
-			this.ibuf = '';
+			let messages = '';
+			if (this.ibuf) {
+				messages += this.ibuf.slice(0);
+				this.ibuf = '';
+			}
+
 			if (idx === data.length - 1) {
 				messages += data.slice(0, -1);
 			} else {