[](https://www.elegantobjects.org) [](https://www.0crat.com/p/C3RFVLU72) [](http://www.rultor.com/p/yegor256/pgtk) [](https://www.jetbrains.com/ruby/) [](https://travis-ci.org/yegor256/pgtk) [](https://ci.appveyor.com/project/yegor256/pgtk) [](http://www.0pdd.com/p?name=yegor256/pgtk) [](http://badge.fury.io/rb/pgtk) [](https://codeclimate.com/github/yegor256/pgtk/maintainability) [](https://github.com/yegor256/pgtk/blob/master/LICENSE.txt) [](https://codecov.io/github/yegor256/pgtk?branch=master) [](https://hitsofcode.com/view/github/yegor256/pgtk) This small Ruby gem helps you integrate [PostgreSQL](https://www.postgresql.org/) with your Ruby web app, through [Liquibase](https://www.liquibase.org/). It also adds a simple connection pool and query processor, to make SQL manipulation simpler. First of all, on top of [Ruby](https://www.ruby-lang.org/en/) and [Bundler](https://bundler.io/) you need to have [PostgreSQL](https://www.postgresql.org/), [Java 8+](https://java.com/en/download/), and [Maven 3.2+](https://maven.apache.org/) installed. In Ubuntu 16+ this should be enough: ```bash $ sudo apt-get install -y postgresql-10 postgresql-client-10 $ sudo apt-get install -y default-jre maven ``` Then, add this to your [`Gemfile`](https://bundler.io/gemfile.html): ```ruby gem 'pgtk' ``` Then, add this to your [`Rakefile`](https://github.com/ruby/rake/blob/master/doc/rakefile.rdoc): ```ruby require 'pgtk/pgsql_task' Pgtk::PgsqlTask.new :pgsql do |t| t.dir = 'target/pgsql' # Temp directory with PostgreSQL files t.fresh_start = true # To delete the directory on every start t.user = 'test' t.password = 'test' t.dbname = 'test' t.yaml = 'target/pgsql-config.yml' # YAML file to be created with connection details end ``` And this too: ```ruby require 'pgtk/liquibase_task' Pgtk::LiquibaseTask.new liquibase: :pgsql do |t| t.master = 'liquibase/master.xml' # Master XML file path t.yaml = ['target/pgsql-config.yml', 'config.yml'] # YAML files with connection details end ``` You should create that `liquibase/master.xml` file in your repository, and a number of other XML files with Liquibase changes. This [example](https://github.com/zold-io/wts.zold.io/tree/master/liquibase) will help you understand them. Now, you can do this: ```bash $ bundle exec rake pgsql liquibase ``` A temporary PostgreSQL server will be started and the entire set of Liquibase SQL changes will be applied. You will be able to connect to it from your application, using the file `target/config.yml`. From inside your app you may find this class useful: ```ruby require 'pgtk/pool' pgsql = Pgtk::Pool.new(Pgtk::Wire::Yaml.new('config.yml')) pgsql.start(5) # Start it with five simultaneous connections name = pgsql.exec('SELECT name FROM user WHERE id = $1', [id])[0]['name'] ``` You may also use it if you need to run a transaction: ```ruby pgsql.transaction do |t| t.exec('DELETE FROM user WHERE id = $1', [id]) t.exec('INSERT INTO user (name, phone) VALUES ($1, $2)', [name, phone]) end ``` To make your PostgreSQL database visible in your unit test, I would recommend you create a method `test_pgsql` in your `test__helper.rb` file (which is `required` in all unit tests) and implement it like this: ```ruby require 'yaml' require 'minitest/autorun' require 'pgtk/pool' module Minitest class Test def test_pgsql config = YAML.load_file() @@test_pgsql ||= Pgtk::Pool.new( Pgtk::Wire::Yaml.new('target/pgsql-config.yml') ).start end end end ``` Should work. Well, it works in [zold-io/wts.zold.io](https://github.com/zold-io/wts.zold.io) and [yegor256/mailanes](https://github.com/yegor256/mailanes). They both are open source, you can see how they use `pgtk`. These open source web apps of mine are using pgtk (check their source code to see how it all works): * [wts.zold.io](https://github.com/zold-io/wts.zold.io) * [mailanes](https://github.com/yegor256/mailanes) * [0rsk](https://github.com/yegor256/0rsk) ## How to contribute Read [these guidelines](https://www.yegor256.com/2014/04/15/github-guidelines.html). Make sure your build is green before you contribute your pull request. You will need to have [Ruby](https://www.ruby-lang.org/en/) 2.3+ and [Bundler](https://bundler.io/) installed. Then: ``` $ bundle update $ bundle exec rake ``` If it's clean and you don't see any error messages, submit your pull request.