capper

:Author: ‘Benedikt Böhm <[email protected]>`_ :Web: github.com/zenops/capper :Git: “git clone github.com/zenops/capper

Capper is a collection of opinionated Capistrano recipes.

Rationale

Most web applications are deployed the same way. While capistrano itself is already quite opinionated, maintaining a multitude of applications feels like copy&paste very fast.

Capper provides sane defaults and many recipes for technologies typically used with Ruby and Python deployments to make “config/deploy.rb“ much more declarative and terse.

Release Notes

v1.0.0 (14/07/2012)

capper has been in production for about 1 year and its API is now considered stable.

Usage

Capper recipes should be loaded via “Capfile“ like this

require “capper”

load “capper/bundler” load “capper/rails” load “capper/rvm” load “capper/unicorn”

load “config/deploy”

load “capper/multistage”

Note: capper does not support capistranos default deploy recipe, instead an enhanced copy is shipped directly with capper and enabled by default.

Multistage


Capper provides a clean DSL syntax for multistage support. In contrast to capistrano-ext you don’t have to create a bunch of tiny files in

“config/deploy/“ but instead use DSL sugar in “config/deploy.rb“

stage :production do

server "app1.example.com", :app, :db, :primary => true
server "app2.example.com", :app

end

stage :staging do

server "staging.example.com", :app, :db, :primary => true
set :rails_env, "staging"
set :branch, "staging"

end

Note: the multistage recipe must be loaded after “config/deploy“ otherwise it cannot know the defined stages.

Templates


Capper provides a powerful yet simple mechanism to upload scripts and config files rendered from templates during deploy. Template files are stored in “config/deploy/templates“ but are rarely needed since capper recipes already contain required template files.

To upload a custom template create an ERb file and upload it with

“upload_template_file“

upload_template_file(“myscript.sh”, “#bin_path/myscript”, :mode => “0755”)

The above command will upload “config/deploy/templates/myscript.sh.erb“ to the specified path. Inside the template all capistrano options (current_path, application, etc) are available.

systemd integration


Capper provides integration with a systemd user session running for the user that is being deployed to. Capper will upload service units and enable/start these accordingly.

Recipes

The following recipes are included in capper.

base


The base recipe is an enhanced version of capistranos default deploy recipe. It is loaded automatically and provides the basic opinions capper has about deployment:

  • The application is deployed to a dedicated user account with the same name as the application.

  • The parent path for these user accounts defaults to “/var/app“.

  • No sudo privileges are ever needed.

  • Releases are cleaned up by default.

  • The application is deployed via “remote_cache“ and “git“.

The “deploy:finalize_update“ task has been enhanced to make symlinks

declarative in “config/deploy.rb“

set :symlinks,

"config/database.yml" => "config/database.yml",
"shared/uploads" => "public/uploads"

The above snippet will create symlinks from “#shared_path/config/database.yml“ to “#release_path/config/database.yml“ and from “#shared_path/uploads“ to “#release_path/public/uploads“ after “deploy:update_code“ has run.

airbrake


The airbrake recipe is merely a copy of airbrakes native capistrano integration without after/before hooks, so airbrake notifications can be enabled on-demand

in stage blocks

stage :production do

...
after "deploy", "airbrake:notify"

end

bundler


The bundler recipe is an extension of bundlers native capistrano integration:

  • During “bundle:install“ it is ensured that a known-to-work bundler version (specified via “bundler_version“) is installed.

  • When used together with the rvm recipe bundles are not installed globally to “shared/bundle“ but instead a gemset specific location is used (“shared/bundle/#gemset“).

  • The option “ruby_exec_prefix“ is set to “bundle exec“ for convenience. (see “ruby“ recipe for details)

delayed_job


The delayed_job recipe provides integration with DelayedJob. A script to start/stop delayed job workers is uploaded to “#bin_path/delayed_job“. The script supports multiple instances and priority ranges.

If monit integration has been enabled via “capper/monit“ workers are automatically (re)started during deploy and can be specified via

“delayed_job_workers“

set :delayed_jobs_workers,

:important => 0..1,
:worker1 => 2..10,
:worker2 => 2..10

django


The django recipe provides setup and migrate tasks for Django.

python


The python recipe provides basic support for Python applications. It will create a symlink from “#current_path/#application“ to “#current_path“ for Python namespace support.

rails


The rails recipe sets the default “rails_env“ to production and includes tasks for deploying the asset pipeline for rails 3.1 applications. It also provdes a migrate task for Rails applications.

rvm


The rvm recipe is an extension to RVMs native capistrano integration. The recipe forces the “rvm_type“ to “:user“ and will automatically determine the ruby version and gemset via the projects “.ruby-version“ and “.ruby-gemset“ files.

A “deploy:setup“ hook is provided to ensure the correct rvm, ruby and rubygems versions are installed on all servers.

ruby


The ruby recipe provides basic support for Ruby applications. It will setup a gemrc file and and variables for “ruby_exec_prefix“ (such as bundler).

thin


The thin recipe provides integration with Thin. A script to manage the thin process is uploaded to “#bin_path/thin“.

unicorn


The unicorn recipe provides integration with Unicorn. A script to manage the unicorn process is uploaded to “#bin_path/unicorn“. Additionally this recipe also manages the unicorn configuration file (in “config/unicorn.rb“).

The following configuration options are provided:

“unicorn_worker_processes“

Number of unicorn workers (default: 4)

“unicorn_timeout“

Timeout after which workers are killed (default: 30)

uwsgi


The uwsgi recipe provides integration with uWSGI. A script to manage the uwsgi process is uploaded to “#bin_path/uwsgi“. Additionally this recipe also manages the uwsgi configuration file (in “config/uwsgi.xml“).

The following configuration options are provided:

“uwsgi_worker_processes“

Number of uwsgi workers (default: 4)

virtualenv


The virtualenv recipe provides “deploy:setup“ hooks for virtualenv support. In addition required Python libraries are installed via pip into this environment.

whenever


The whenever recipe is a simplified version of whenevers native capistrano integration. With one application per user account the whole crontab can be used for whenever. Additionally this recipe take the “ruby_exec_prefix“ setting into account. To define the target servers user the cron role.

server "app1.example.com", :app, :cron

node deployment


read big-elephants.com/2012-07/deploying-node-with-capistrano/ about the the use case.

nave


The nave recipe sets up nave Virtual Environments for Node

set :use_nave, true set :nave_dir, ‘~/.nave’ set :node_version, ‘0.8.1’

npm


The npm recipe runs npm install after deploy:update_code. When used with the nave recipe npm install runs “nave use <ver> npm install“. Not it is recommended to add npm-shrinkwrap.json into version control to manage npm

dependencies

set :npm_cmd, “npm”

forever


The forever recipe starts your app as daemon in the background.

When used with the nave recipe it runs “nave use <ver> forever [action]“

set :forever_cmd, “forever” # e.g. “./node_modules/.bin/forever” set :node_env, “production” # the NODE_ENV environment variable used to start the script set :main_js, “index.js” # e.g. “./build/main.js” the script you want to start

Contributing to capper

  • Check out the latest master to make sure the feature hasn’t been implemented or the bug hasn’t been fixed yet

  • Check out the issue tracker to make sure someone already hasn’t requested it and/or contributed it

  • Fork the project

  • Start a feature/bugfix branch

  • Commit and push until you are happy with your contribution

Copyright

Copyright © 2011-2012 Benedikt Böhm. See LICENSE for further details.