larvitdb

larvitdb

DB pool wrapper for node.js This module is used to share a mysql/mariadb pool of connections between modules, classes, files etc.

It also logs with winston if there is a database error, so you do not need to fetch the database error manually each time.

Installation

npm i larvitdb

Usage

The module must first be required and then configured. Make this in your main application file:

const db = require('larvitdb');

db.setup({
	"connectionLimit":   10,
	"socketPath":        "/var/run/mysqld/mysqld.sock",
	"user":              "foo",
	"password":          "bar",
	"charset":           "utf8_general_ci",
	"supportBigNumbers": true,
	"database":          "my_database_name"
});

See list of native options here. Then you can just require the module in your other files for usage, like this:

A direct query

const db = require('larvitdb');

db.query('SELECT 1 + 1 AS solution', function(err, rows, fields) {
	console.log('dbmodel: The solution is: ', rows[0].solution);
});

Or, if a connection is needed:

const db = require('larvitdb');

db.pool.getConnection(function(err, dbCon) {
	const sql = 'SELECT * FROM users WHERE username LIKE ' + dbCon.escape(postData);

	dbCon.query(sql, function(err, rows) {
		dbCon.release(); // Always release your connection when the query is done

		if (err)
			throw err;
	});
});

You dont need to get a connection to escape though. You can do like this:

const db = require('larvitdb');

db.query('SELECT * FROM users WHERE id = ?', [userId], function(err, results) {
  // ...
});

Advanced configuration - recoverable errors

Sometimes recoverable errors happend in the database. One such example is deadlocks in a cluster. Here we'll provide an example of how to make the database layer retry a query 5 times if a deadlock happends, before giving up.

const db = require('larvitdb');

db.setup({
	"connectionLimit":   10,
	"socketPath":        "/var/run/mysqld/mysqld.sock",
	"user":              "foo",
	"password":          "bar",
	"charset":           "utf8_general_ci",
	"supportBigNumbers": true,
	"database":          "my_database_name",
	"retries":           5, // Defaults to 3 if omitted
	"recoverableErrors": ["ER_LOCK_DEADLOCK"] // What error codes to retry
});

// If this query fails with a deadlock, it will be retried up to 5 times.
// On each retry a warning will be logged with winston
// If the 5th retry fails, an error will be logged and the callback will be called with an error
db.query('DELETE FROM tmpTable LIMIT 10');

Custom functions

Remove all tables from current database

This function will clean the current database from all tables.

const db = require('larvitdb');

db.removeAllTables();