Blue-Green deployment solution for Capistrano, using symbolic links between releases.
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
docs
lib
spec
.gitignore
.rspec
.ruby-gemset
.ruby-version
CHANGELOG.md
Gemfile
Gemfile.lock
LICENSE.txt
README.md
Rakefile
cap_blue_green_deploy.gemspec

README.md

Cap Blue Green Deploy Gem Version Code Climate Travis Coverage Status

Blue-Green deployment solution for Capistrano, using symbolic links between releases.

Blue Green Concept

Learn more about Blue Green Deployment with Martin Fowler

Presentations about this gem and the concept:

Introduction

Cap Blue Green Deployment is a non canonical Blue Green solution, based on symlinks. Instead of having blue and green, we have pre and live. Pre is always validation environment and live it's production environment.

architecture

You can do as many deploys as you need to pre without affecting your live env. Changing symlinks you can easily put your code from validation to production environment.

Prerequisite

  • Capistrano 2 (Capistrano 3 coming soon)

Installation

Add this line to your application's Gemfile:

gem 'cap_blue_green_deploy'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cap_blue_green_deploy

And then, require the gem script under your capistrano configuration file (Capfile, deploy.rb, ...):

require 'cap_blue_green_deploy'

Usage

Understanding the deploy folder:

  • current: Pre environment. Used to test and validate your application.
  • current_live: Live environment. Your production access goes here. This dir name can be customized in custom variables, see below
  • previous_live: Last live release. Used to do the rollback action of current_live. This dir name can be customized in custom variables, see below

Deploy Commands:

  • Going to Pre cap deploy:blue_green:pre

    This command is an alias for cap deploy default task. It will run the deploy process and create the current release

  • Going to Live cap deploy:blue_green:live

    This command will change symlinks of current_live dir to use the same release path of current dir. And also create the previous_live symlink to track the last current live release used.

  • Rolling back cap deploy:blue_green:rollback

    This command will change the current_live symlink to use the same destination of previous_live symlink.

  • Cleanup cap deploy:blue_green:cleanup

    This is the same behavior of the default capistrano cleanup deploy:cleanup, but the current, current_live and previous_live releases will be preserved and not removed.

    This lib automatically rewrite the default deploy:cleanup to use this new cleanup function.

    Don't forget that you need to add the cleanup callback manually in your capistrano file: after "deploy:update", "deploy:cleanup"

  • Custom Variables

    You can change the default values by overwriting them in your capistrano file. The default values are:

    • keep_releases: 5
    • blue_green_live_dir: "current_live"
    • blue_green_previous_dir: "previous_live"

How to Play

Custom Variables used

  • set :keep_releases, 2
  • set :blue_green_live_dir, "current_live"
  • set :blue_green_previous_dir, "previous_live"

1. Starting with clean server Clean server

2. Running cap deploy:setup to prepare the server Deploy setup

3. Running cap deploy three times to populate the release folder (cleanup code removes one old release) Deploy Deploy

4. Going to live cap deploy:blue_green:live (current_live dir will be created. No changes in releases dir) Blue Green Live Blue Green Live

5. Running two more deploy with cap deploy (current_live will not change. Cleanup remove one old release.) Deploy Deploy

6. Going to live again with cap deploy:blue_green:live (At this time, previous_live will be created, targeting the current_live release before change it. No changes in releases dir) Blue Green Live Blue Green Live

7. Something goes wrong... Rollbacking with cap deploy:blue_green:rollback (The current_live will change to target the same release of previous_live. No changes in releases dir) Blue Green Rollback Blue Green Rollback

8. Running one more deploy with cap deploy (current_live and previous_live will not change. Cleanup remove one old release.)* Deploy Deploy

9. Going to live again with cap deploy:blue_green:live Deploy

Changing current_live and previous_live variables to use custom names (custom_live_path, custom_rollback_path) Custom names

Contributors

Contributing

  1. Fork it
  2. Create your feature branch (git checkout -b my-new-feature)
  3. Commit your changes (git commit -am 'Add some feature')
  4. Push to the branch (git push origin my-new-feature)
  5. Create new Pull Request