A few years ago, I checked off an item on my Open Source Bucket List when I pitched—and ultimately contributed—a brand new feature to HashiCorp's Vagrant: command aliases. While aliases have been a core Vagrant feature for some time, there hasn't been a lot of coverage about what they are, and why they really matter.
An expansion on the concept of shell-based aliases, user-configurable aliases within Vagrant provide a more contextual outlet for tuning Vagrant in a way that isn't operating system or shell dependent. Personally, I use Vagrant on both Windows and macOS machines, and while Vagrant is cross-platform, my command line aliases are not.
Who Cares?
Originally inspired by Git's own alias functionality, aliases make your Vagrant experience simpler, easier, and more familiar by allowing you to create your own custom Vagrant commands. In a world where software developers tune and configure their environments for optimum productivity, aliases allow us to abstract away the nuances of a given tool in favor of our own preferred usability patterns.
Take, for example, a common workflow that I tend to follow: completely burning a running Vagrant box to the ground. Generally, this involves executing a vagrant destroy followed by removing the .vagrant directory from the project. Instead of running both of these commands every time, I can instead create an alias called vagrant eradicate that does all that sweet, sweet destruction on my behalf.
But How?
Defined using a standard key = value format, Vagrant aliases work the same way as Git aliases. By adding these aliases to the Vagrant alias file (which can be found either at VAGRANT_HOME/aliases or in a custom file defined using the VAGRANT_ALIAS_FILE environment variable), you can start crafting your own aliases almost immediately.
Let's say that we want to implement the vagrant eradicate command example from above. This can be done by dropping the following line into your Vagrant aliases file:
eradicate = !vagrant destroy && rm -rf .vagrant
Once added, the vagrant eradicate command should be available for all your burninating needs. Using this type of key = value format, there are two types of aliases that can be defined: internal and external aliases.
Internal Aliases
Internal command aliases call Vagrant's CLI class directly. This allows you to alias one Vagrant command to another Vagrant command. This technique can be very useful for creating simple commands that you think should exist. For example, if vagrant stop feels more intuitive than vagrant halt, the following alias definitions would make that change possible:
stop = halt
Or, maybe you want to be able to force halt a running Vagrant box. Adding parameters and options to the alias can be done as well:
stop = halt -f
This would make the following commands functionally equivalent:
vagrant stop vagrant halt -f
External Aliases
While internal aliases can be used to define more intuitive Vagrant commands, external command aliases are used to define Vagrant commands with brand new functionality. Similarly to Git aliases, these aliases are prefixed with the ! character, which tells the command interpreter that the alias should be executed as a shell command.
As an example, let's say that you want to be able to view the processor and memory utilization of the active project's running Vagrant box. To do this, you could define a vagrant stats command that returns the required information in an easy-to-read format, like so:
stats = !ps aux | grep "[V]BoxHeadless" | grep $(cat .vagrant/machines/default/virtualbox/id) | awk '{ printf("CPU: %.02f%%, Memory: %.02f%%", $3, $4) }'
The above alias, from within the context of an active Vagrant project, would print the CPU and memory utilization of the running box directly to the console:
CPU: 4.20%, Memory: 11.00%
What Else?
What started out as a small idea turned into one that solved a very real pain point for me personally, and it's one that has benefited me for years now. These are just a few examples of the types of aliases you can create in Vagrant, but what are some other examples you can think of (or are currently using)?
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