unleash.unleash/docs/developer-guide.md

# Developer Guide

## PostgreSQL
To run and develop unleash you need to have PostgreSQL databse (PostgreSQL v.9.5.x or newer) locally.


### Create a local unleash databases in postgres

```bash
$ psql postgres <<SQL
CREATE USER unleash_user WITH PASSWORD 'passord';
CREATE DATABASE unleash;
GRANT ALL PRIVILEGES ON DATABASE unleash to unleash_user;
CREATE DATABASE unleash_test;
GRANT ALL PRIVILEGES ON DATABASE unleash_test to unleash_user;
SQL
```

Then set env vars:

(Optional as unleash will asume these as default values).

```
export DATABASE_URL=postgres://unleash_user:passord@localhost:5432/unleash
export TEST_DATABASE_URL=postgres://unleash_user:passord@localhost:5432/unleash_test
```

## PostgreSQL with docker
If you dont want to install PostgreSQL locally you can spin up an instance with docker. 
We have created a script to ease this process: `scripts/docker-postgres.sh`


## Commands

```
// Install dependencies
npm install

// Build unleash-frontend 
// (yes this is a bit wierd and be easier when we have a release of the frontend artifact).
// You can of course "npm link unleash-frontend" instead 
cd node_modules/unleash-frontend && npm install

// Start server in development
npm start:dev

// Admin dashboard
http://localhost:4242

// Feature API:
http://localhost:4242/api/features

// Execute tests in all packages:
npm test
```

## Database changes

We use database migrations to track database changes. 

### Making a schema change
In order to run migrations you will set the environment variable for DATABASE_URL

`export DATABASE_URL=postgres://unleash_user:passord@localhost:5432/unleash`

Use db-migrate to create new migrations file. 

```bash
> npm run db-migrate -- create YOUR-MIGRATION-NAME
```

All migrations requires on `up` and one `down` method. 

Example of a typical migration:

```js
/* eslint camelcase: "off" */
'use strict';

exports.up = function (db, cb) {
    db.createTable('examples', {
        id: { type: 'int', primaryKey: true, notNull: true },
        created_at: { type: 'timestamp', defaultValue: 'now()' },
    }, cb);
};

exports.down = function (db, cb) {
    return db.dropTable('examples', cb);
};
``` 

Test your migrations:

```bash
> npm run db-migrate -- up
> npm run db-migrate -- down
```


## Publishing / Releasing new packages

Please run `npm run nsp` nad `npm run lint` checks before publishing.

Run `npm run publish` to start the publishing process.
Lerna is setup with independent versioning so you will be prompted with version per package, and lerna will update all the versions across packages.

`npm run publish:dry`