Add method gets the instance public IP when provider is AWS

README.md

@@ -29,6 +29,25 @@ At the moment, the only things you need, are the hostname and a :private_network
 
 This ip and the hostname will be used for the entry in the /etc/hosts file.
 
+## For AWS
+
+If you'd like AWS as a provider using [vagrant-aws](https://github.com/mitchellh/vagrant-aws) or other plugin,
+this plugin will detect the instance public IP by the tag infomations.  
+For example, [vagrant-aws](https://github.com/mitchellh/vagrant-aws) configures a tag infomations like the following.
+
+    config.vm.provider :aws do |aws, override|
+      aws.tags = {
+        "Name" => "vagrant",
+        ...
+      }
+      aws.elastic_ip = true
+      ...
+    end
+
+* [AWS CLI](https://aws.amazon.com/cli/) is required
+* Make the tag infomations be unique for the instance
+* Enable Elastic IP for the instance
+
 ##  Versions
 
 ### 0.0.11

lib/vagrant-hostsupdater/HostsUpdater.rb

@@ -1,14 +1,20 @@
+require 'open3'
+
 module VagrantPlugins
   module HostsUpdater
     module HostsUpdater
       @@hosts_path = Vagrant::Util::Platform.windows? ? File.expand_path('system32/drivers/etc/hosts', ENV['windir']) : '/etc/hosts'
 
       def getIps
         ips = []
-        @machine.config.vm.networks.each do |network|
-          key, options = network[0], network[1]
-          ip = options[:ip] if key == :private_network
-          ips.push(ip) if ip
+        if ip = getAwsPublicIp
+          ips.push(ip)
+        else
+          @machine.config.vm.networks.each do |network|
+            key, options = network[0], network[1]
+            ip = options[:ip] if key == :private_network
+            ips.push(ip) if ip
+          end
         end
         return ips
       end
@@ -116,6 +122,26 @@ def sudo(command)
           `sudo #{command}`
         end
       end
+
+
+      private
+
+      def getAwsPublicIp
+        aws_conf = @machine.config.vm.get_provider_config(:aws)
+        return nil if ! aws_conf.is_a?(VagrantPlugins::AWS::Config)
+        filters = ( aws_conf.tags || [] ).map {|k,v| sprintf('"Name=tag:%s,Values=%s"', k, v) }.join(' ')
+        return nil if filters == ''
+        cmd = 'aws ec2 describe-instances --filter '+filters
+        stdout, stderr, stat = Open3.capture3(cmd)
+        @ui.error sprintf("Failed to execute '%s' : %s", cmd, stderr) if stderr != ''
+        return nil if stat.exitstatus != 0
+        begin
+          return JSON.parse(stdout)["Reservations"].first()["Instances"].first()["PublicIpAddress"]
+        rescue => e
+          @ui.error sprintf("Failed to get IP from the result of '%s' : %s", cmd, e.message)
+          return nil
+        end
+      end
     end
   end
 end