Capistrano Deploy Lock

Lock a server during deploy, to prevent people from deploying at the same time.

Installation

Add this line to your application's Gemfile:

gem 'capistrano_deploy_lock'

And then execute:

$ bundle

Add this line to your config/deploy.rb:

require 'capistrano/deploy_lock'

Usage

Your deploys will now be protected by a lock. Simply run cap deploy as usual. However, if someone else tries to deploy at the same time, their deploy will show a message like this, and exit:

*** Deploy locked 3 minutes ago by 'ndbroadbent'
*** Message: Deploying master branch
*** Expires in 12 minutes

The default deploy lock will expire after 15 minutes. This is so that crashed or interrupted deploys don't leave a stale lock behind.

The following tasks will be run before deploy:

• deploy:check_lock
  • Checks for an existing deploy lock. Aborts deploy if a lock exists and it wasn't created by you.
• deploy:refresh_lock
  • If you previously created a lock, this task ensures that your lock won't expire before the default expiry time
• deploy:create_lock
  • If no locks already exist, a default lock will be created with the message: Deploying <branch>

The following task will be run after deploy:

• deploy:unlock
  • Removes any default deploy locks. If you set a custom lock, it will not be removed at this step.
  • You can remove a custom deploy lock by running cap deploy:unlock by itself, or by chaining deploy:unlock:force at the end of the command.

Tasks

deploy:with_lock

Deploy the latest revision with a custom deploy lock. This lock will not be removed at the end of the deploy.

deploy:lock

Sets a custom deploy lock. You will receive two prompts for input:

• Lock Message:

Type the reason for the lock. This message will be displayed to any developers who attempt to deploy.

• Expire lock at? (optional):

Set an expiry time for the lock. Leave this blank to make the lock last until someone removes it with cap deploy:unlock.

If the chronic gem is available, you can type natural language times like 2 hours, or tomorrow at 6am. If not, you must type times in a format that DateTime.parse() can handle, such as 06:30:00 or 2012-12-12 00:00:00.

deploy:unlock

Removes the deploy lock. Will not remove a custom deploy lock when it is chained after deploy:lock.

deploy:unlock:force

Removes any deploy lock, even when chained after deploy:lock.

deploy:check_lock

Check if server is locked. If the deploy lock was not created by you, an error will be raised and the deploy will abort. If the lock was created by you, the deploy will pause for 4 seconds, which gives you time to press Ctrl+C to cancel the deploy.

This task is also responsible for deleting any expired locks.

deploy:refresh_lock

Refreshes the current lock's expiry time if it is less than the default time.

Configuration

If your deploys usually take longer than 15 minutes, you can configure the default expiry time with:

set :default_lock_expiry, (20 * 60)   # Sets the default expiry to 20 minutes

The lock file will be created at #{shared_path}/capistrano.lock.yml by default. You can configure this with:

set :deploy_lockfile, "path/to/deploy/lock/file"

MOTD script

If you install the gem on your server, you can use the cap_deploy_lock_msg script to display the lock status when you login via SSH.

Usage:

cap_deploy_lock_msg <application_name> <stage> <path/to/lock_file.yml>

If you are using update-motd on Ubuntu, create /etc/update-motd.d/10-deploy-lock with the following:

#!/bin/sh
/usr/local/bin/cap_deploy_lock_msg application stage /var/www/apps/application/shared/capistrano.lock.yml

Thanks

Special thanks to David Bock, who wrote the deploy_lock.rb script that this is based on.

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