Node AWS lambda with pg-promise

Question

I've written a lambda to perform simple steps to a redshift database. It runs multiple queries with transaction. I use pg-promise.

'use strict';
const config = require('./redshift_config_from_env');
const redshiftConn = `pg://${config.user}:${config.password}@${config.host}/${config.database}`;
const pgp = require('pg-promise')();
var tableCopyQuery = function(tableName) {
 return `
 ALTER TABLE ${tableName}_temp
 RENAME TO ${tableName}_process;
 CREATE TABLE ${tableName}_temp (LIKE ${tableName}_process);`;
};
var insertQuery = function(tableName) {
 return `
 INSERT INTO ${tableName}
 SELECT DISTINCT ${tableName}_process.*
 FROM ${tableName}_process
 LEFT JOIN ${tableName} USING (id)
 WHERE ${tableName}.id IS NULL
 ORDER BY ${tableName}_process.id;
 DROP TABLE ${tableName}_process;`;
};
exports.handler = function(event, context) {
 const client = pgp(redshiftConn);
 client.tx(function (t) {
 return t.batch([
 t.none(tableCopyQuery('active_connections')),
 t.none(insertQuery('active_connections')),
 t.none(tableCopyQuery('active_downloads')),
 t.none(insertQuery('active_downloads'))
 ]);
 })
 .then(function () {
 context.succeed(`Successfully Refreshed.`);
 })
 .catch(function (error) {
 context.fail(`Failed to run queries : ${JSON.stringify(error)}`);
 });
};

I think I may move sql queries into .sql file outside of the function.

Maybe the var could be turned into let because the scope will fit?

Answer 1

You shouldn't create the database object on every function call. Read this answer (and its question) for an example of this.