abhishek77in

Database do's and don'ts

This is a generic guidline that applies mostly to Ruby on Rails and Postgres, but can be usefull for running any database migrations in CI.

Table of contents

• Table of contents
• Zero downtime migrations
  • Resources
• Basic tenets

abhishek77in

require 'resolv'

url = 'www.diagnofy.in'
begin
  r = Resolv::DNS.open do |dns|
    dns.timeouts = 1
    dns.getresource(url, Resolv::DNS::Resource::IN::CNAME)
  end
  r.name.to_s # => return alias domain
rescue Resolv::ResolvError => e

abhishek77in

user  nginx;
worker_processes  5;

error_log  /var/log/nginx.error.log;
pid        /var/run/nginx.pid;

events {
  worker_connections  1024;
}

abhishek77in

#!/bin/bash

# -----------------------------------------------------------------------
# Installs Ruby 2.3 using rbenv/ruby-build on the Raspberry Pi (Raspbian)
#
# Run from the web:
#   bash <(curl -s raw_script_url_here)
# -----------------------------------------------------------------------

# Set up variables

abhishek77in

class SubdomainValidator < ActiveModel::EachValidator
  # http://matthewhutchinson.net/2010/10/27/rails-3-subdomain-validation-activemodeleachvalidator
  # http://www.rails-dev.com/custom-validators-in-ruby-on-rails-4

  def validate_each(object, attribute, value)
    return unless value.present?
    reserved_names = %w(www ftp mail pop smtp admin ssl sftp)
    reserved_names = options[:reserved] if options[:reserved]
    if reserved_names.include?(value)
      object.errors[attribute] << 'cannot be a reserved name'

abhishek77in

namespace :db do  desc "Backup database to AWS-S3"
  task :backup => [:environment] do
    datestamp = Time.now.strftime("%Y-%m-%d_%H-%M-%S")
    backup_filename = "#{Rails.root.basename}-#{datestamp}.sql"
    db_config = ActiveRecord::Base.configurations[Rails.env]

    # process backup
    `mysqldump -u #{db_config['username']} -p#{db_config['password']} -i -c -q #{db_config['database']} > tmp/#{backup_filename}`
    `gzip -9 tmp/#{backup_filename}`
    puts "Created backup: #{backup_filename}"