This small Ruby gem helps you integrate PostgreSQL with your Ruby web app, through Liquibase. It also adds a simple connection pool and query processor, to make SQL manipulation simpler.
First of all, on top of Ruby and Bundler you need to have PostgreSQL, Java 8+, and Maven 3.2+ installed. In Ubuntu 16+ this should be enough:
$ sudo apt-get install -y postgresql-10 postgresql-client-10
$ sudo apt-get install -y default-jre mavenThen, add this to your Gemfile:
gem 'pgtk'Then, add this to your Rakefile:
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
endAnd this too:
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' # YAML file with connection details
endYou should create that liquibase/master.xml file in your repository,
and a number of other XML files with Liquibase changes. This
example
will help you understand them.
Now, you can do this:
$ bundle exec rake pgsql liquibaseA 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:
require 'pgtk/pool'
yaml = YAML.load_file('config.yml')
pgsql = Pgtk::Pool.new(
port: yaml['pgsql']['port'],
dbname: yaml['pgsql']['dbname'],
user: yaml['pgsql']['user'],
password: yaml['pgsql']['password']
)
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 direct access to the connection, for example in order to run a set of requests in a transaction:
pgsql.connect do |c|
c.transaction do |conn|
conn.exec_params('DELETE FROM user WHERE id = $1', [id])
conn.exec_params('INSERT INTO user (name, phone) VALUES ($1, $2)', [name, phone])
end
endTo 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:
require 'yaml'
require 'minitest/autorun'
require 'pgtk/pool'
module Minitest
class Test
def test_pgsql
config = YAML.load_file('target/pgsql-config.yml')
@test_pgsql ||= Pgtk::Pool.new(
host: config['pgsql']['host'],
port: config['pgsql']['port'],
dbname: config['pgsql']['dbname'],
user: config['pgsql']['user'],
password: config['pgsql']['password']
).start
end
end
endShould work. Well, it works in zold-io/wts.zold.io
and yegor256/mailanes. They both are
open source, you can see how they use pgtk.
Read these guidelines. Make sure your build is green before you contribute your pull request. You will need to have Ruby 2.3+ and Bundler installed. Then:
$ bundle update
$ bundle exec rake
If it's clean and you don't see any error messages, submit your pull request.
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