How to use the createPool function from generic-pool

generic-pool.createPool is a function that creates a pool of reusable resources, such as database connections or network sockets, that can be borrowed and returned by multiple parts of a program, improving performance and efficiency.

How does generic-pool.createPool work?

When called, the generic-pool.createPool function initializes a new pool of resources with a specified minimum and maximum number of items. As resource requests are made by different parts of a program, the pool either provides a resource from the pool, if one is available, or creates a new resource if the pool is not yet at its maximum capacity. When a resource is no longer needed, it is returned to the pool so that it can be reused by other parts of the program. The pool also has configurable options to control how resources are created, validated, and destroyed, ensuring that only healthy resources are provided to program components.

Ai Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
const { createPool } = require("generic-pool");
const mysql = require("mysql");

// Set up a factory function to create new database connections
const factory = {
  create: function () {
    return mysql.createConnection({
      host: "localhost",
      user: "db_user",
      password: "db_password",
      database: "my_database",
    });
  },
  destroy: function (connection) {
    connection.end();
  },
};

// Set up pool options
const options = {
  max: 10,
  min: 2,
  acquireTimeoutMillis: 10000,
  idleTimeoutMillis: 30000,
};

// Create a new pool of database connections
const pool = createPool(factory, options);

// Borrow a connection from the pool and execute a query
pool.acquire().then((connection) => {
  connection.query("SELECT * FROM users", (error, results) => {
    // Handle results or error here
    // ...
    // Release the connection back to the pool when done
    pool.release(connection);
  });
});

In this example, the createPool function is used to create a pool of up to 10 database connections, with a minimum of 2 connections always available. The factory object is used to create and destroy database connections, with the create method creating a new connection to a MySQL database using the mysql package, and the destroy method ending the connection when it is no longer needed. Program components can borrow a connection from the pool by calling the pool.acquire() method, which returns a promise that resolves with a connection object when a connection is available. When the program component is finished using the connection, it releases it back to the pool by calling pool.release(connection). The options object also includes some additional configuration options, such as acquireTimeoutMillis, which specifies how long the program component should wait to acquire a connection from the pool before timing out, and idleTimeoutMillis, which specifies how long a connection can remain idle in the pool before it is destroyed.