Connection pool is never closed with node-oracledb and nodejs - node.js

Question

I'm making a little API using Node Js and Oracle, using node-oracledb for that. I have been guided by the following article: API with OracleDB and Node JS
The project files contain the following:
/services/web-server.js
const http = require('http');
const morgan = require('morgan');
const express = require('express');
const webServerConfig = require('../config/web-server');
let httpServer;
function initialize(){
return new Promise((resolve, reject) => {
const app = express();
httpServer = http.createServer(app);
app.use(morgan('combined'));
app.get('/', (req, res) => {
res.end('Hello World');
});
httpServer.listen(webServerConfig.port, err => {
if(err){
reject(err);
return;
}
console.log(`Web server listening on localhost:${webServerConfig.port}`);
resolve();
});
});
}
module.exports.initialize = initialize;
function close(){
return new Promise((resolve, reject) => {
httpServer.close(err => {
if(err){
reject(err);
return;
}
resolve();
});
});
}
module.exports.close = close;
/services/database.js
const oracledb = require('oracledb');
const dbConfig = require('../config/database');
async function initialize(){
const pool = await oracledb.createPool(dbConfig.gtsmpPool);
}
module.exports.initialize = initialize;
async function close(){
await oracledb.getPool().close();
}
module.exports.close = close;
And /index.js
const webServer = require('./services/web-server');
const database = require('./services/database');
const dbConfig = require('./config/database');
const defaultThreadPoolSize = 4;
// Increase thread pool size by poolMax
process.env.UV_THREADPOOL_SIZE = dbConfig.gtsmpPool.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('Initializing web server module');
await webServer.initialize();
}catch(err){
console.error(err);
process.exit(1); // Non-zero failure code
}
}
startup();
async function shutdown(e){
let err = e;
console.log('Shutting down');
try{
console.log('Closing web server module');
await webServer.close();
}catch(e){
console.log('Encountered error', e);
err = err || e;
}
console.log('Exiting process');
try{
console.log('Closing database module');
await database.close();
}catch(err){
console.log('Encountered error', err);
err = err || e;
}
if(err){
process.exit(1); // Non-zero failure code
}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');
console.error(err);
shutdown(err);
});
/config/database.js
module.exports = {
gtsmpPool: {
user: process.env.GTSMP_USER,
password: process.env.GTSMP_PASSWORD,
connectString: process.env.GTSMP_CONNECTIONSTRING,
poolMin: 10,
poolMax: 10,
poolIncrement: 0
}
};
The connection to the database is succesful. The problem is that when I want to terminate the application and close the connection pool, the await statement oracledb.getPool().close() never gets resolved and seems to get stuck.
If I try to forcefully finish I get the following messages
Encountered error Error [ERR_SERVER_NOT_RUNNING]: Server is not running.
at Server.close (net.js:1604:12)
at Object.onceWrapper (events.js:416:28)
at Server.emit (events.js:310:20)
at emitCloseNT (net.js:1657:8)
at processTicksAndRejections (internal/process/task_queues.js:83:21) {
code: 'ERR_SERVER_NOT_RUNNING'
And
Encountered error Error: NJS-002: invalid pool
I'm using Oracle 18c XE on docker container, Node v12.16.3 and instantclient_18_5
Any idea how to fix it?
Thanks.

Answer 1

There are some notes in the node-oracledb pool example...
// Get the pool from the pool cache and close it when no
// connections are in use, or force it closed after 10 seconds.
// If this hangs, you may need DISABLE_OOB=ON in a sqlnet.ora file.
// This setting should not be needed if both Oracle Client and Oracle
// Database are 19c (or later).
await oracledb.getPool().close(10);