vagrant/docs/rake.md

96 lines
3.2 KiB
Markdown

---
layout: documentation
title: Documentation - Rake Integration
---
# Rake Integration
Sometimes the commands Vagrant provides aren't enough. Maybe you need
a command that shuts down the system gracefully, or a command that makes
sure that before starting up some files are in place, or _anything_.
Luckily, Vagrant is coded in such a way that extending it via rake
tasks isn't too hard! Being completely honest, allowing for this sort of
extensibility wasn't an initial design goal, but was a positive side
effect from Vagrant's modular design. After seeing the possibilities
this provides, we've decided future versions of Vagrant will attempt to
provide developers with more tools to ease the process of extending
Vagrant. For now, however, its still completely possible to power Vagrant
through Rake or any other Ruby-based script.
## Loading Vagrant
Vagrant is loaded like any other Ruby library. At the top of the Rakefile
or Ruby script being made to control Vagrant, load the library:
{% highlight ruby %}
require 'vagrant'
{% endhighlight %}
**Note:** Depending how your system is setup, you may need to `require 'rubygems'`
as well.
## Loading the Vagrant Environment
The first step to doing anything with Vagrant is to make sure that the
environment is loaded. Each Vagrant project has its own "environment"
which simply encapsulates the configuration, SSH access, VM, etc.
of that project.
Loading the environment sets up all the paths, loads the virtual
machine (if one exists), and loads the configuration. Loading the
environment for the current directory is a one-liner:
{% highlight ruby %}
env = Vagrant::Environment.load!
{% endhighlight %}
If you're working in a separate directory or you're writing a script that
will be used with multiple Vagrant projects, you can load a specific
Vagrant environment by passing in a path:
{% highlight ruby %}
env = Vagrant::Environment.load!("/path/to/my/project")
{% endhighlight %}
## Executing Commands
All available `vagrant` command line tools are available in code through
the `commands` accessor on the environment instance. This allows you to
easily to run the command line tools in the context of an environment
without any extra fuss. The following is a simple rake task that simply
does the equivalent of `vagrant up` but does some extra, useless things
around it:
{% highlight ruby %}
# Example of emulating vagrant up with some code around it
task :up do
puts "About to run vagrant-up..."
env = Vagrant::Environment.load!
env.commands.up
puts "Finished running vagrant-up"
end
{% endhighlight %}
## SSH Commands
Perhaps you want to write a rake task that does some commands within the
virtual server setup? This can be done through the `ssh` accessor of the
environment, which is an instance of `Vagrant::SSH`. `Vagrant::SSH`
is simply a wrapper around `Net::SSH` and the objects returned are typically
`Net::SSH` objects.
The following example is a useful example showing how to create a graceful
shutdown command:
{% highlight ruby %}
task :graceful_down do
env = Vagrant::Environment.load!
env.require_persisted_vm
env.ssh.execute do |ssh|
ssh.exec!("sudo halt")
end
end
{% endhighlight %}
This example also shows `env.require_persisted_vm` which simply errors and
exits if there is no Vagrant VM created yet.