/grandprix

Deploy strategy planner

Primary LanguageRubyMIT LicenseMIT

Grandprix

Grandprix is a small project with the sole function of imposing an ordering for a happens-before relation. It was created to help with deploy orchestration, to sort out which system should be upgraded before another, based on their dependency relationship. For instance, say we have four systems: a backend server, two frontend servers and a client. And we want to deploy new versions of every system.

                    
                        ----------------
               ---------|  frontend_A  |<--------
               v        ----------------        |
    -------------                              ------------  
    |  backend  |                              |  client  | 
    -------------                              ------------ 
               ^        ----------------        |
               ---------|  frontend_B  |<--------
                        ----------------

You give grandprix a description of the ordering dependencies and a list of elements:

client:
  after: [frontend_A, frontend_B]

frontend_A:
  after: [backend]

frontend_B:
  after: [backend]

backend
client
frontend_A
frontend_B

And grandprix will output a correct ordering:

backend
frontend_A
frontend_B
client

We call the description of the dependencies a topology.

Using from the command line

Instalation

The project is packaged as a rubygem, just make sure you have Ruby 1.9 installed and run:

$ gem install grandprix

Usage

An executable called grandprix will be installed, and can be called like this:

$ topology -t topology_file elements_file

The elements file argument can be omitted and grandprix will read them from the standard in.

The doc/sample/simple directory has sample topology and elements files.

Using as a library

Instalation

Add this line to your application's Gemfile:

gem 'grandprix'

And then execute:

$ bundle

Usage

The programatic API is very similar to the command line tool. Just call the run! instance method on the Grandprix::Runner class, passing in a hash representing the topology and an array of elements.

The doc/sample/as_a_library directory has an example ruby script calling grandprix programatically.

More

Grandprix offers a few more conveniences, illustrated on the doc/sample directories:

  • Elements can contain extra data that will carry over to the output, such as version numbers. Just append an equals sign and the info you want to each element. Check out the elements_with_extra_info directory.
  • The topology itself can define information that will propagate to the output, in the form of an annotation attribute. See the annotated_topology directory.
  • Besides declaring that an element needs to come after others, grandprix also allows for an element to specify that it must always be accompanied by another, via the alongside attribute. This will extend the provided elements input. See the alongside_elements and alongside_elements_2 directories.

Contributing

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