pg-migration-promise

A Node.js package to help with database migrations -- that is, changes to your database over time.

It has a Promises based interface and development focused on performance and quality.

The high level idea is to bring your projects' database up to the latest version in an automatic, consistent manor across many environments (development, staging and production).

Status

This project is ready for consumption. There are two options to include it in your project. Please know that this is still under development and it's best if you frequently check npm for updates

NPM (preferred)

The current official release is available in NPM. You can install it with npm install --save pg-migration-promise.

npm's git integration.

More information here: https://docs.npmjs.com/files/package.json#github-urls

Examples

A basic example is provided below. This product is intended to aid keeping several developers database instances up to date no matter which version is pulled from source control. Do note, however, that this product doesn't support going backwards -- only forwards.

API Documentation

The full API Documentation can be found at https://frankv01.github.io/pg-migration/

A quick summary is follows.

Migration Definition File

The migration object is a JSON element that contains your SQL to create and modify the definition of the database. Basic structure is this:

{
  "1.0.0": {
    "tables": ["CREATE TABLE ..."],
    "data": ["INSERT ..."],
    "indexes": []
  },
  "1.0.1": {
    "tables": ["DROP TABLE ..."],
    "data": ["UPDATE"],
    "indexes": []
  }
}

With node, you can define a .json file and require it to a variable or directly in the object's construction. The migration definition file can also be .js which allows you to define logic in your migrations. The only requirement is that the json structure is adhered to.

App Initialization

After the migration object is setup, preferably in a different module, you execute code such as the following in a bootstrap or start up module. Where, exactly, is up to you as long as it's prior to database access by your application.

pg-migration returns a promise so you can perform steps after with then or handle errors which can result from bad SQL or, lets face it, a package bug.

const pg_migration = require('pg-migration-promise');
const d = pg_migration({
  connection: 'postgres://john:123@localhost:5432/products', //or an object 
  migrations: require('migrations.json') //or a .js file
}); //returns a promise
d.catch(function(er) {
  console.log('pg-migration: Error occurred during pg-migration', er);
});

Contributions

All contributions are welcomed. First time contributes are especially encouraged as this is a new, relatively simple project with straight forward requirements. If you want to break into Node JS, this is a good project.

I am open to suggestions as well; Node is not my "day time forte" but has quickly become a technology of interest. That said, I'm trying to take queues from Nightwatch and pg-promise and am -- at a high level -- following those ideas amongst my own.

Development Setup

The following are the instructions to set this project up on your workstations for hacking/exploration or for contributions. The intention is to get the dependencies installed so that you can run the unit tests. Unit tests are good!

Dependencies

There are few dependencies that you must manually install. Node.js and postgres.

Please install these via your method of choice. My suggestions follow

• Node
  • Windows: Use installer from the web site
  • Mac OS X: Use the installer or the Linux method
  • Linux: I'd suggest using nvm
• Postgres
  • Windows: Installer
  • Mac OS X: Postgres.app
  • Linux: ??

Get the source

First, clone the project with your tool of choice. I can't cover all tools so I'll provide instructions with the git cli.

cd ~/github #or where you keep you github/git repos
git clone https://github.com/FrankV01/pg-migration.git
cd pg-migration
npm install

Assuming the above commands all execute successfully, the following should pass 100%; Run the following:

npm test

And you should get results similar to the following. The these results were trimmed:

[...]
index
    ✓ no arguments throws exception
    ✓ missing migration argument
    ✓ missing connection argument
    ✓ calls dbMigrate with options; returns a promise


  17 passing (2s)

Wiki

Please see the wiki for more information: https://github.com/FrankV01/pg-migration/wiki