Add support for looking up AMIs with the EC2 API

README.md

@@ -81,23 +81,23 @@ token) through config.  See the `aws_access_key_id` and `aws_secret_access_key`
 config sections below to see how to specify these in your .kitchen.yml or
 through environment variables.  If you would like to specify your session token
 use the environment variable `AWS_SESSION_TOKEN`.
-1. The shared credentials ini file at `~/.aws/credentials`.  You can specify 
+1. The shared credentials ini file at `~/.aws/credentials`.  You can specify
 multiple profiles in this file and select one with the `AWS_PROFILE`
 environment variable or the `shared_credentials_profile` driver config.  Read
 [this][credentials_docs] for more information.
 1. From an instance profile when running on EC2.  This accesses the local
 metadata service to discover the local instance's IAM instance profile.
 
 This precedence order is taken from http://docs.aws.amazon.com/sdkforruby/api/index.html#Configuration
-  
+
 The first method attempted that works will be used.  IE, if you want to auth
 using the instance profile, you must not set any of the access key configs
 or environment variables, and you must not specify a `~/.aws/credentials`
 file.
 
 Because the Test Kitchen test should be checked into source control and ran
 through CI we no longer recommend storing the AWS credentials in the
-`.kitchen.yml` file.  Instead, specify them as environment variables or in the 
+`.kitchen.yml` file.  Instead, specify them as environment variables or in the
 `~/.aws/credentials` file.
 
 ## Windows Configuration
@@ -186,6 +186,18 @@ The default will be determined by the `aws_region` chosen and the Platform
 name, if a default exists (see [amis.json][ami_json]). If a default cannot be
 computed, then the default is `nil`.
 
+### image\_search
+
+Searches the EC2 API for the latest AMI ID that matches the given [filters](http://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeImages.html).
+
+For example, a search for the latest AMI that matches a given image name looks
+like:
+
+```yaml
+image_search:
+  name: Windows_Server-2012-R2_RTM-English-64Bit-Base-*
+```
+
 ### region
 
 **Required** The AWS [region][region_docs] to use.

lib/kitchen/driver/ec2.rb

@@ -237,6 +237,17 @@ def destroy(state)
         state.delete(:hostname)
       end
 
+      def lookup_ami(filters_hash)
+        filters = []
+        filters_hash.each do |key, value|
+          filters.push(:name => key.to_s, :values => Array(value))
+        end
+        images = ec2.resource.images(:filters => filters).sort do |ami1, ami2|
+          Time.parse(ami1.creation_date) <=> Time.parse(ami2.creation_date)
+        end
+        images.last && images.last.id
+      end
+
       def ubuntu_ami(region, platform_name)
         release = amis["ubuntu_releases"][platform_name]
         Ubuntu.release(release).amis.find do |ami|
@@ -251,6 +262,8 @@ def default_ami
         if instance.platform.name.start_with?("ubuntu")
           ami = ubuntu_ami(config[:region], instance.platform.name)
           ami && ami.name
+        elsif !config[:image_search].nil?
+          lookup_ami(config[:image_search])
         else
           region = amis["regions"][config[:region]]
           region && region[instance.platform.name]

spec/kitchen/driver/ec2_spec.rb

@@ -424,6 +424,50 @@
     end
   end
 
+  describe "#lookup_ami" do
+    let(:resource) { double("actual resource") }
+
+    let(:filters) { { :name => "ami_name" } }
+    let(:aws_filters) do
+      { :filters => [{ :name => "name", :values => ["ami_name"] }] }
+    end
+
+    before do
+      allow(client).to receive(:resource).and_return(resource)
+    end
+
+    context "when one ami found" do
+      let(:ami_id) { "ami-a1b2c3d4" }
+      let(:date) { "2015-06-10T03:47:20.000Z" }
+      let(:ami_list) { [double("ami", :id => ami_id, :creation_date => date)] }
+
+      it "returns the ami id" do
+        expect(resource).to receive(:images).with(aws_filters). \
+          and_return(ami_list)
+        expect(driver.lookup_ami(filters)).to eq(ami_id)
+      end
+    end
+
+    context "when more than one ami found" do
+      let(:date_older) { "2015-06-10T03:47:20.000Z" }
+      let(:date_newer) { "2015-06-11T03:47:20.000Z" }
+      let(:ami_id_older) { "ami-a1b2c3d4" }
+      let(:ami_id_newer) { "ami-e5f6g7h8" }
+      let(:ami_list) do
+        [
+          double("ami", :id => ami_id_older, :creation_date => date_older),
+          double("ami", :id => ami_id_newer, :creation_date => date_newer)
+        ]
+      end
+
+      it "returns most recently created ami id" do
+        expect(resource).to receive(:images).with(aws_filters). \
+          and_return(ami_list)
+        expect(driver.lookup_ami(filters)).to eq(ami_id_newer)
+      end
+    end
+  end
+
   describe "#default_ami" do
     context "when platform is ubuntu" do
       let(:config) { { :aws_ssh_key_id => "key" } }
@@ -436,6 +480,17 @@
         expect(driver.default_ami).to eq(ami_data[0])
       end
     end
+
+    context "when ami_search is provided" do
+      let(:config) { { :image_search => {} } }
+      let(:ami_id) { "ami-xxxxxxxx" }
+
+      it "searches for an image id" do
+        expect(driver).to receive(:lookup_ami).with(config[:image_search]). \
+          and_return(ami_id)
+        expect(driver.default_ami).to eq(ami_id)
+      end
+    end
   end
 
 end