Added files for part 2 - database basics

Author: Dan McGhan

javascript/rest-api/part-2-database-basics/hr_app/config/database.js

@@ -0,0 +1,10 @@
+module.exports = {
+  hrPool: {
+    user: process.env.HR_USER,
+    password: process.env.HR_PASSWORD,
+    connectString: process.env.HR_CONNECTIONSTRING,
+    poolMin: 10,
+    poolMax: 10,
+    poolIncrement: 0
+  }
+};

javascript/rest-api/part-2-database-basics/hr_app/config/web-server.js

@@ -0,0 +1,3 @@
+module.exports = {
+  port: process.env.HTTP_PORT || 3000
+};

javascript/rest-api/part-2-database-basics/hr_app/index.js

@@ -0,0 +1,85 @@
+const webServer = require('./services/web-server.js');
+const database = require('./services/database.js');
+const dbConfig = require('./config/database.js');
+const defaultThreadPoolSize = 4;
+
+// Increase thread pool size by poolMax
+process.env.UV_THREADPOOL_SIZE = dbConfig.hrPool.poolMax + defaultThreadPoolSize;
+
+async function startup() {
+  console.log('Starting application');
+
+  try {
+    console.log('Initializing database module');
+
+    await database.initialize(); 
+  } catch (err) {
+    console.error(err);
+
+    process.exit(1); // Non-zero failure code
+  }
+
+  try {
+    console.log('Starting web server');
+
+    await webServer.start(); 
+  } catch (err) {
+    console.error(err);
+
+    process.exit(1); // Non-zero failure code
+  }
+}
+
+startup();
+
+async function shutdown(e) {
+  let err = e;
+    
+  console.log('Shutting down application');
+
+  try {
+    console.log('Closing web server');
+
+    await webServer.stop();
+  } catch (e) {
+    console.error(e);
+
+    err = err || e;
+  }
+
+  try {
+    console.log('Closing database module');
+
+    await database.close(); 
+  } catch (e) {
+    console.error(e);
+
+    err = err || e;
+  }
+
+  console.log('Exiting process');
+
+  if (err) {
+    process.exit(1);
+  } else {
+    process.exit(0);
+  }
+}
+
+process.on('SIGTERM', () => {
+  console.log('Received SIGTERM');
+
+  shutdown();
+});
+
+process.on('SIGINT', () => {
+  console.log('Received SIGINT');
+
+  shutdown();
+});
+
+process.on('uncaughtException', err => {
+  console.log('Uncaught exception', err);
+
+  shutdown(err);
+});