= Capistrano rsync_with_remote_cache

This gem provides a deployment strategy for Capistrano which combines rsync with a remote cache, allowing fast 
deployments from Subversion repositories behind firewalls.

== Requirements

This gem requires Capistrano 2.0.0 and higher. Git support requires Capistrano 2.1.0 or higher.

This gem has only been tested with Subversion and Git. It is unlikely to be supported for other SCM systems unless we 
adopt them at Viget Labs, or get outside help.

This gem requires and <tt>rsync</tt> command line utilities on the local and remote hosts. It also requires either 
<tt>svn</tt> or <tt>git</tt> on the local host, but not the remote host.

This gem is tested primarily on Mac OS X and Linux. It may work with a Windows local host, but is not tested or 
supported. Like Capistrano itself, it will not work with a Windows remote host.

== Gem preliminaries

To create the gem, run <tt>gem build capistrano_rsync_with_remote_cache.gemspec</tt> in this directory.

To use this deployment strategy, add this line to your configuration:

<tt>set :deploy_via, :rsync_with_remote_cache</tt>

== How it works

This strategy maintains two cache directories:

* The local cache directory is a checkout from the SCM repository. The local cache directory is specified with the 
<tt>local_cache</tt> variable in the configuration. If not specified, it will default to ".rsync_cache" in the same 
directory as the Capfile.
* The remote cache directory is an rsync copy of the local cache directory. The remote cache directory is specified with 
the <tt>repository_cache</tt> variable in the configuration (this name comes from the remote_cache strategy that ships 
with Capistrano, and has been maintained for compatibility.) If not specified, it will default to "shared/cached-copy" 
(again, for compatibility with remote_cache.)

Deployment happens in three major steps. First, the local cache directory is processed. If it does not exist, it is 
created with a checkout of the revision to be deployed. If it exists, it is updated to the revision to be deployed.

Second, rsync runs on the local side to sync the remote cache to the local cache. When the rsync is complete, the remote 
cache should be an exact replica of the local cache.

Finally, a copy of the remote cache is made in the appropriate release directory. The end result is the same as if the 
code had been checked out directly on the remote server, as in the default strategy.

Copyright (c) 2007, 2008 Mark Cornick of Viget Labs, released under the MIT license