From 7bf1f9c4591404c7756344c8db8a2f35e395654b Mon Sep 17 00:00:00 2001
From: FragginWagon <greg.r.jacobs@gmail.com>
Date: Thu, 29 Jan 2026 13:19:18 +0000
Subject: [PATCH] =?UTF-8?q?=F0=9F=94=A7=20Add=20graceful=20shutdown=20util?=
 =?UTF-8?q?ity=20for=20server?=
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---
 .../server/utils/graceful-shutdown.js         | 136 ++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 code/websites/pokedex.online/server/utils/graceful-shutdown.js

diff --git a/code/websites/pokedex.online/server/utils/graceful-shutdown.js b/code/websites/pokedex.online/server/utils/graceful-shutdown.js
new file mode 100644
index 0000000..6965066
--- /dev/null
+++ b/code/websites/pokedex.online/server/utils/graceful-shutdown.js
@@ -0,0 +1,136 @@
+/**
+ * Graceful Shutdown Handler
+ * 
+ * Handles server shutdown gracefully by:
+ * - Closing server to stop accepting new connections
+ * - Waiting for existing connections to finish
+ * - Cleaning up resources
+ * - Exiting with appropriate code
+ */
+
+import logger from './logger.js';
+
+/**
+ * Setup graceful shutdown handlers for Express server
+ * @param {Object} server - HTTP server instance
+ * @param {Object} options - Configuration options
+ */
+export function setupGracefulShutdown(server, options = {}) {
+  const {
+    timeout = 30000, // 30 seconds
+    onShutdown = null // Optional cleanup function
+  } = options;
+
+  let isShuttingDown = false;
+  const connections = new Set();
+
+  // Track all connections
+  server.on('connection', (connection) => {
+    connections.add(connection);
+    connection.on('close', () => {
+      connections.delete(connection);
+    });
+  });
+
+  /**
+   * Perform graceful shutdown
+   * @param {string} signal - Signal that triggered shutdown
+   */
+  async function shutdown(signal) {
+    if (isShuttingDown) {
+      logger.warn('Shutdown already in progress, forcing exit');
+      process.exit(1);
+      return;
+    }
+
+    isShuttingDown = true;
+    logger.info(`Received ${signal}, starting graceful shutdown...`);
+
+    // Stop accepting new connections
+    server.close(() => {
+      logger.info('Server closed, all requests completed');
+    });
+
+    // Set shutdown timeout
+    const shutdownTimeout = setTimeout(() => {
+      logger.error(`Shutdown timeout (${timeout}ms), forcing exit`);
+      connections.forEach((conn) => conn.destroy());
+      process.exit(1);
+    }, timeout);
+
+    try {
+      // Run custom cleanup if provided
+      if (onShutdown) {
+        logger.info('Running custom shutdown cleanup...');
+        await onShutdown();
+      }
+
+      // Wait for all connections to close
+      logger.info(`Waiting for ${connections.size} connections to close...`);
+      
+      // Close all idle connections
+      connections.forEach((conn) => {
+        if (!conn.destroyed) {
+          conn.end();
+        }
+      });
+
+      // Give connections time to finish
+      await new Promise((resolve) => {
+        const checkInterval = setInterval(() => {
+          if (connections.size === 0) {
+            clearInterval(checkInterval);
+            resolve();
+          }
+        }, 100);
+      });
+
+      clearTimeout(shutdownTimeout);
+      logger.info('Graceful shutdown complete');
+      process.exit(0);
+    } catch (error) {
+      logger.error('Error during shutdown', { error: error.message });
+      clearTimeout(shutdownTimeout);
+      process.exit(1);
+    }
+  }
+
+  // Register shutdown handlers for various signals
+  const signals = ['SIGTERM', 'SIGINT', 'SIGUSR2'];
+  signals.forEach((signal) => {
+    process.on(signal, () => shutdown(signal));
+  });
+
+  logger.info('Graceful shutdown handlers registered');
+}
+
+/**
+ * Health check middleware that returns 503 during shutdown
+ */
+export function createHealthCheckMiddleware() {
+  let isHealthy = true;
+
+  process.on('SIGTERM', () => {
+    isHealthy = false;
+  });
+  process.on('SIGINT', () => {
+    isHealthy = false;
+  });
+
+  return (req, res) => {
+    if (!isHealthy) {
+      return res.status(503).json({
+        status: 'shutting_down',
+        message: 'Server is shutting down'
+      });
+    }
+
+    res.json({
+      status: 'ok',
+      uptime: process.uptime(),
+      timestamp: new Date().toISOString(),
+      memory: process.memoryUsage(),
+      environment: process.env.NODE_ENV
+    });
+  };
+}