Further WebSocket enhancements along with other corrections, touch #456.

.env.sample

@@ -88,7 +88,7 @@ WEB_SOCKET_ENABLE = false
 WEB_SOCKET_RECONNECT = false
 WEB_SOCKET_REJECT_UNAUTHORIZED = false
 WEB_SOCKET_PING_TIMEOUT = 16000
-WEB_SOCKET_RECONNECT_ATTEMPTS = 3
 WEB_SOCKET_RECONNECT_INTERVAL = 3000
+WEB_SOCKET_RECONNECT_ATTEMPTS = 3
 WEB_SOCKET_URL =
 WEB_SOCKET_SECRET =

.eslintrc.cjs

@@ -24,13 +24,7 @@ module.exports = {
     }
   ],
   rules: {
-    'no-unused-vars': 0,
-    'import/no-cycle': 2,
-    'prettier/prettier': [
-      'error',
-      {
-        endOfLine: require('os').EOL === '\r\n' ? 'crlf' : 'lf'
-      }
-    ]
+    'no-unused-vars': 'off',
+    'import/no-cycle': 'error'
   }
 };

README.md

@@ -376,6 +376,17 @@ These variables are set in your environment and take precedence over options fro
 - `DEBUG_SLOW_MO`: Slows down Puppeteer operations by the specified number of milliseconds (defaults to `0`).
 - `DEBUG_DEBUGGING_PORT`: Specifies the debugging port (defaults to `9222`).
 
+### WebSocket Config
+
+- `WEB_SOCKET_ENABLE`: Enables or disables the WebSocket connection (defaults to `false`).
+- `WEB_SOCKET_RECONNECT`: Controls whether or not to try reconnecting to the WebSocket server in case of a disconnect (defaults to `false`).
+- `WEB_SOCKET_REJECT_UNAUTHORIZED`: Determines whether the client verifies the server's SSL/TLS certificate during the handshake process (defaults to `false`).
+- `WEB_SOCKET_PING_TIMEOUT`: The timeout, in milliseconds, for the heartbeat mechanism between the client and server (defaults to `16000`).
+- `WEB_SOCKET_RECONNECT_INTERVAL`: The interval, in milliseconds, for the reconnect attempt (defaults to `3000`).
+- `WEB_SOCKET_RECONNECT_ATTEMPTS`: The number of reconnect attempts before returning a connection error (defaults to `3`).
+- `WEB_SOCKET_URL`: The URL of the WebSocket server (defaults to ``).
+- `WEB_SOCKET_SECRET`: The secret used to create a JSON Web Token sent to the WebSocket server (defaults to ``).
+
 ## Command Line Arguments
 
 To supply command line arguments, add them as flags when running the application:
@@ -448,6 +459,14 @@ _Available options:_
 - `--dumpio`: Redirects browser process stdout and stderr to process.stdout and process.stderr (defaults to `false`).
 - `--slowMo`: Slows down Puppeteer operations by the specified number of milliseconds (defaults to `0`).
 - `--debuggingPort`: Specifies the debugging port (defaults to `9222`).
+- `--enableWs`: Enables or disables the WebSocket connection (defaults to `false`).
+- `--wsReconnect`: Controls whether or not to try reconnecting to the WebSocket server in case of a disconnect (defaults to `false`).
+- `--wsrejectUnauthorized`: Determines whether the client verifies the server's SSL/TLS certificate during the handshake process (defaults to `false`).
+- `--wsPingTimeout`: The timeout, in milliseconds, for the heartbeat mechanism between the client and server (defaults to `16000`).
+- `--wsReconnectInterval`: The interval, in milliseconds, for the reconnect attempt (defaults to `3000`).
+- `--wsReconnectAttempts`: The number of reconnect attempts before returning a connection error (defaults to `3`).
+- `--wsUrl`: The URL of the WebSocket server (defaults to ``).
+- `--wsSecret`: The secret used to create a JSON Web Token sent to the WebSocket server (defaults to ``).
 
 # HTTP Server
 

lib/export.js

@@ -239,8 +239,8 @@ export default async (page, chart, options) => {
           // eslint-disable-next-line no-undef
           const { chartHeight, chartWidth } = window.Highcharts.charts[0];
 
-          // No need for such scale manipulation in case of other types of exports
-          // Reset the zoom for other exports than to SVGs
+          // No need for such scale manipulation in case of other types
+          // of exports. Reset the zoom for other exports than to SVGs
           // eslint-disable-next-line no-undef
           document.body.style.zoom = 1;
 

lib/pool.js

@@ -401,12 +401,19 @@ export function getPoolInfo() {
   log(5, `[pool] The number of resources waiting to be acquired: ${pending}.`);
 }
 
+/**
+ * Gets the statistic of a pool instace about exports.
+ */
+export function getStats() {
+  return stats;
+}
+
 export default {
   initPool,
   killPool,
   postWork,
   getPool,
   getPoolInfo,
   getPoolInfoJSON,
-  getStats: () => stats
+  getStats
 };

lib/resource_release.js

@@ -12,9 +12,10 @@ See LICENSE file in root for details.
 
 *******************************************************************************/
 
-import { clearAllIntervals } from './intervals.js';
+import { clearAllTimers } from './timers.js';
 import { killPool } from './pool.js';
 import { closeServers } from './server/server.js';
+import { terminateClients } from './server/web_socket.js';
 
 /**
  * Clean up function to trigger before ending process for the graceful shutdown.
@@ -24,8 +25,11 @@ import { closeServers } from './server/server.js';
 export const shutdownCleanUp = async (exitCode) => {
   // Await freeing all resources
   await Promise.allSettled([
-    // Clear all ongoing intervals
-    clearAllIntervals(),
+    // Clear all ongoing timers
+    clearAllTimers(),
+
+    // Terminate all connected WebSocket clients
+    terminateClients(),
 
     // Get available server instances (HTTP/HTTPS) and close them
     closeServers(),

lib/schemas/config.js

@@ -675,6 +675,69 @@ export const defaultConfig = {
       envLink: 'DEBUG_DEBUGGING_PORT',
       description: 'Specifies the debugging port.'
     }
+  },
+  webSocket: {
+    enable: {
+      value: false,
+      type: 'boolean',
+      envLink: 'WEB_SOCKET_ENABLE',
+      cliName: 'enableWs',
+      description: 'Enables or disables the WebSocket connection.'
+    },
+    reconnect: {
+      value: false,
+      type: 'boolean',
+      envLink: 'WEB_SOCKET_RECONNECT',
+      cliName: 'wsReconnect',
+      description:
+        'Controls whether or not to try reconnecting to the WebSocket server in case of a disconnect.'
+    },
+    rejectUnauthorized: {
+      value: false,
+      type: 'boolean',
+      envLink: 'WEB_SOCKET_REJECT_UNAUTHORIZED',
+      cliName: 'wsrejectUnauthorized',
+      description:
+        "Determines whether the client verifies the server's SSL/TLS certificate during the handshake process."
+    },
+    pingTimeout: {
+      value: 16000,
+      type: 'number',
+      envLink: 'WEB_SOCKET_PING_TIMEOUT',
+      cliName: 'wsPingTimeout',
+      description:
+        'The timeout, in milliseconds, for the heartbeat mechanism between the client and server.'
+    },
+    reconnectInterval: {
+      value: 3000,
+      type: 'number',
+      envLink: 'WEB_SOCKET_RECONNECT_INTERVAL',
+      cliName: 'wsReconnectInterval',
+      description: 'The interval, in milliseconds, for the reconnect attempt.'
+    },
+    reconnectAttempts: {
+      value: 3,
+      type: 'number',
+      envLink: 'WEB_SOCKET_RECONNECT_ATTEMPTS',
+      cliName: 'wsReconnectAttempts',
+      description:
+        'The number of reconnect attempts before returning a connection error.'
+    },
+    url: {
+      value: false,
+      type: 'string',
+      envLink: 'WEB_SOCKET_URL',
+      cliName: 'wsUrl',
+      description: 'The URL of the WebSocket server.'
+    },
+    secret: {
+      value: false,
+      type: 'string',
+      envLink: 'WEB_SOCKET_SECRET',
+      cliName: 'wsSecret',
+      description:
+        'The secret used to create a JSON Web Token sent to the WebSocket server.'
+    }
   }
 };
 
@@ -1097,6 +1160,56 @@ export const promptsConfig = {
       message: 'The port number for debugging',
       initial: defaultConfig.debug.debuggingPort.value
     }
+  ],
+  webSocket: [
+    {
+      type: 'toggle',
+      name: 'enable',
+      message: 'Enables WebSocket connection',
+      initial: defaultConfig.webSocket.enable.value
+    },
+    {
+      type: 'toggle',
+      name: 'reconnect',
+      message: 'The reconnect mechanism for WebSocket connection',
+      initial: defaultConfig.webSocket.reconnect.value
+    },
+    {
+      type: 'toggle',
+      name: 'rejectUnauthorized',
+      message: 'Reject connection if WebSocket is not secured, SSL/TLS',
+      initial: defaultConfig.webSocket.rejectUnauthorized.value
+    },
+    {
+      type: 'number',
+      name: 'pingTimeout',
+      message: 'Timeout for the hearbeat mechanism',
+      initial: defaultConfig.webSocket.pingTimeout.value
+    },
+    {
+      type: 'number',
+      name: 'reconnectInterval',
+      message: 'Interval for the reconnect mechanism',
+      initial: defaultConfig.webSocket.reconnectInterval.value
+    },
+    {
+      type: 'number',
+      name: 'reconnectAttempts',
+      message: 'The number of reconnect attempts',
+      initial: defaultConfig.webSocket.reconnectAttempts.value
+    },
+    {
+      type: 'text',
+      name: 'url',
+      message: 'The URL of the WebSocket server',
+      initial: defaultConfig.webSocket.url.value
+    },
+    {
+      type: 'text',
+      name: 'secret',
+      message: 'The secret for the JWT to WebSocket server',
+      initial: defaultConfig.webSocket.secret.value
+    }
   ]
 };
 

lib/server/routes/export.js

@@ -103,7 +103,7 @@ const exportHandler = async (request, response, next) => {
     const defaultOptions = getOptions();
 
     // Get the first WebSocket client
-    const webSocketClient = getWebSocketClient().values().next().value;
+    const webSocketClient = getWebSocketClient().next().value;
 
     const body = request.body;
     const id = ++requestsCounter;

lib/server/routes/health.js

@@ -17,8 +17,8 @@ import { join as pather } from 'path';
 import { log } from '../../logger.js';
 
 import { version } from '../../cache.js';
-import { addInterval } from '../../intervals.js';
-import pool from '../../pool.js';
+import { addTimer } from '../../timers.js';
+import { getStats, getPoolInfoJSON } from '../../pool.js';
 import { __dirname } from '../../utils.js';
 
 const pkgFile = JSON.parse(readFileSync(pather(__dirname, 'package.json')));
@@ -48,7 +48,7 @@ function calculateMovingAverage() {
  */
 export const startSuccessRate = () =>
   setInterval(() => {
-    const stats = pool.getStats();
+    const stats = getStats();
     const successRatio =
       stats.exportAttempts === 0
         ? 1
@@ -71,10 +71,10 @@ export default function addHealthRoutes(app) {
 
   // Start processing success rate ratio interval and save its id to the array
   // for the graceful clearing on shutdown with injected addInterval funtion
-  addInterval(startSuccessRate());
+  addTimer(startSuccessRate());
 
   app.get('/health', (_, res) => {
-    const stats = pool.getStats();
+    const stats = getStats();
     const period = successRates.length;
     const movingAverage = calculateMovingAverage();
 
@@ -95,7 +95,7 @@ export default function addHealthRoutes(app) {
       exportAttempts: stats.exportAttempts,
       sucessRatio: (stats.performedExports / stats.exportAttempts) * 100,
       // eslint-disable-next-line import/no-named-as-default-member
-      pool: pool.getPoolInfoJSON(),
+      pool: getPoolInfoJSON(),
 
       // Moving average
       period,