Momentum

Shared utilities for managing and deploying OpsWorks apps at Artsy.

Installation

Add this line to your application's Gemfile, probably in the :development group:

gem 'momentum', require: false

In your application's Rakefile, add this line above the load_tasks command:

begin
  require 'momentum'  # necessary b/c tasks from gems in :development group aren't loaded automatically
  Momentum.configure do |conf|
    conf[:app_base_name] = 'your_app_name'
  end
rescue LoadError
  # momentum should only be installed in development
end

And then execute:

$ bundle
$ gem install librarian-chef  # ideally this would be in the bundle, but has conflicts
$ bundle exec rake momentum:init

Naming

It's assumed that stacks are named with an app name and modifier, such as todo-production. The modifier is usually an environment, but might also be a developer name or some other label, such todo-joey.

Rake Tasks

This gem adds a few useful rake tasks to your project. By default, the aws_id and aws_secret arguments are taken from AWS_ID and AWS_SECRET ENV variables. The to argument refers to the modifier mentioned above (e.g., production). It's appended to the configured app_base_name to form the stack name.

momentum:init

Initialize a default librarian-chef config.

ow:config[to,aws_id,aws_secret]

Print the custom configuration values for the given stack. E.g.:

bundle exec rake ow:config[joey]

ow:config:from_env[to,aws_id,aws_secret]

Add the given stack's custom configuration values to the current task's ENV. Can be prepended to other rake tasks that depend on the ENV, e.g.:

bundle exec rake ow:config:from_env[production] some:migration

ow:console[to,env,aws_id,aws_secret]

Start a rails console on the given remote OpsWorks stack. Chooses an instance of the rails-app layer by default, or the configured rails_console_layer if provided. E.g.:

bundle exec rake ow:console[production]

For stacks with labels not matching the Rails environment (e.g., reflection-joey), provide a 2nd argument with the desired environment:

bundle exec rake ow:console[joey,staging]

ow:cookbooks:update[to,aws_id,aws_secret]

Zip, upload, and propagate custom cookbooks to the given stack. Or, more concisely:

bundle exec rake ow:cookbooks:update[staging]
# or just:
bundle exec rake ow:cookbooks:update:staging

ow:deploy[to,migrate_db,aws_id,aws_secret]

Trigger an OpsWorks deploy to the given stack. By default, deploys app to all running instances of the rails-app layer, or the list configured in app_layers. E.g.:

bundle exec rake ow:deploy[staging]
# or just:
bundle exec rake ow:deploy:staging
# if you want to trigger database migrations at the same time, add the additional flag
bundle exec rake ow:deploy:migrations[staging]

ow:logs[to,instance,log_path,aws_id,aws_secret]

Execute a tail -f (follow) command against a remote log path on the given remote OpsWorks instance and stack. The path may include wildcards. E.g.:

bundle exec rake ow:logs[staging,rails-app1,/srv/www/myapp/shared/log/staging.log]

ow:ssh[to,layer_or_instance,aws_id,aws_secret]

SSH to an OpsWorks instance. If the layer_or_instance argument is a layer, an online instance is chosen randomly from the layer. Otherwise, the name of an online instance is expected. E.g.:

bundle exec rake ow:ssh[staging,memcached]
# or...
bundle exec rake ow:ssh[staging,rails-app1]

Configuration:

• app_base_name - Your app's name. Stacks are assumed to be named like appbasename-env (e.g., gravity-staging or reflection-joey).
• app_layers - Array of OpsWorks layer names to which this rails app should be deployed. Default: ['rails-app']
• cookbooks_install_path - Local path where librarian-chef will install cookbooks. Default: tmp/cookbooks
• custom_cookbooks_bucket - Bucket to which custom cookbooks are uploaded. Default: artsy-cookbooks
• rails_console_layer - The OpsWorks layer used for SSH-ing and starting a rails console. Default: rails-app

To Do

• git/branch helpers
• Integrate librarian-chef as legit dependency once rails/chef conflicts resolved
• Tests

© 2014 Artsy. See LICENSE for details.