Facter for AWS EC2 Instance Tags

aws_tags.rb

require 'open-uri'
require 'aws-sdk-core'

def aws_metadata(path)
	return open("http://169.254.169.254/latest/meta-data/#{path}").read.split("\n")[0]
end

Aws.config[:region] = aws_metadata('placement/availability-zone')[0..-2]
Aws.config[:credentials] = Aws::InstanceProfileCredentials.new
ec2 = Aws::EC2::Client.new

filters = [
	{name: "resource-type", values: ['instance']},
	{name: "resource-id", values: [aws_metadata('instance-id')]},
]

tags = {}

ec2.describe_tags(:filters => filters).each do |resp|
	resp[:tags].each do |tag|
		tags[tag.key] = tag.value
		
		Facter.add("aws_tag_#{tag.key}") do
			setcode do
				tag.value
			end
		end
	end
end

Facter.add(:aws_tags) do
	setcode do
		tags.to_json
	end
end

Installation

Check out the Facter documentation

Requirements

• gem 'aws-sdk-core'
• Instance must have an IAM Role with read-only permission for EC2 resources (at least ec2:Describe*). See here and here

Usage:

The value of each tag can be accessed using fact aws_tag_<tag_name>, or all tags in JSON format using fact aws_tags. Ex:

Single tag

$ facter aws_tag_name
my_ec2_instance

$ facter aws_tag_environment
Test

All Tags

$ facter aws_tags
[{"Name": "my_ec2_instance", "Environment": "Test"}]

All edits, comments and suggestions are welcome!!