Added computed/sane defaults!!

Allows for computed defaults for a select list of pre-determined
platforms.

Currently a .kitchen.yml file of the following would work:

    ---
    driver_plugin: ec2
    driver_config:
      # ...

    platforms:
      - name: ubuntu-10.04
      - name: ubuntu-12.04
      - name: ubuntu-12.10
      - name: ubuntu-13.04
      - name: centos-6.4
      - name: debian-7.1.0

    suites:
      - name: default
        run_list:
          - recipe[something]

Author: fnichol

README.md

@@ -18,6 +18,46 @@ will need access to an [AWS][aws_site] account.
 
 Please read the [Driver usage][driver_usage] page for more details.
 
+## <a name="default-config"></a> Default Configuration
+
+This driver can determine AMI and username login for a select number of
+platforms in each region. Currently, the following platform names are
+supported:
+
+```ruby
+---
+platforms:
+- name: ubuntu-10.04
+- name: ubuntu-12.04
+- name: ubuntu-12.10
+- name: ubuntu-13.04
+- name: centos-6.4
+- name: debian-7.1.0
+```
+
+This will effectively generate a configuration similar to:
+
+```ruby
+---
+platforms:
+- name: ubuntu-10.04
+  driver_config:
+    image_id: ami-1ab3ce73
+    username: ubuntu
+- name: ubuntu-12.04
+  driver_config:
+    image_id: ami-2f115c46
+    username: ubuntu
+# ...
+- name: centos-6.4
+  driver_config:
+    image_id: ami-bf5021d6
+    username: root
+# ...
+```
+
+For specific default values, please consult [amis.json][amis_json].
+
 ## <a name="config"></a> Configuration
 
 ### <a name="config-az"></a> availability\_zone
@@ -30,19 +70,22 @@ The default is `"us-east-1b"`.
 
 **Required** The AWS [access key id][credentials_docs] to use.
 
-The default is unset, or `nil`.
+The default will be read from the `AWS_ACCESS_KEY` environment variable if set,
+or `nil` otherwise.
 
 ### <a name="config-aws-secret-access-key"></a> aws\_secret\_access\_key
 
 **Required** The AWS [secret access key][credentials_docs] to use.
 
-The default is unset, or `nil`.
+The default will be read from the `AWS_SECRET_KEY` environment variable if set,
+or `nil` otherwise.
 
 ### <a name="config-aws-ssh-key-id"></a> aws\_ssh\_key\_id
 
 **Required** The EC2 [SSH key id][key_id_docs] to use.
 
-The default is unset, or `nil`.
+The default will be read from the `AWS_SSH_KEY_ID` environment variable if set,
+or `nil` otherwise.
 
 ### <a name="config-flavor-id"></a> flavor\_id
 
@@ -61,7 +104,9 @@ The default is `["default"]`.
 
 **Required** The EC2 [AMI id][ami_docs] to use.
 
-The default is unset, or `nil`.
+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`.
 
 ### <a name="config-port"></a> port
 
@@ -120,7 +165,9 @@ The default is `{ "created-by" => "test-kitchen" }`.
 
 The SSH username that will be used to communicate with the instance.
 
-The default is `"root"`.
+The default will be determined by the Platform name, if a default exists (see
+[amis.json][amis_json]). If a default cannot be computed, then the default is
+`"root"`.
 
 ## <a name="example"></a> Example
 
@@ -214,6 +261,7 @@ Apache 2.0 (see [LICENSE][license])
 [driver_usage]:     http://docs.kitchen-ci.org/drivers/usage
 [chef_omnibus_dl]:  http://www.opscode.com/chef/install/
 
+[amis_json]:        https://github.com/opscode/kitchen-ec2/blob/master/data/amis.json
 [ami_docs]:         http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ComponentsAMIs.html
 [aws_site]:         http://aws.amazon.com/
 [credentials_docs]: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/SettingUp_CommandLine.html#using-credentials-access-key

data/amis.json

@@ -0,0 +1,81 @@
+{
+  "regions": {
+    "ap-northeast-1": {
+      "ubuntu-10.04": "ami-8326b382",
+      "ubuntu-12.04": "ami-bb9a08ba",
+      "ubuntu-12.10": "ami-4556c544",
+      "ubuntu-13.04": "ami-97099a96",
+      "centos-6.4": "ami-9ffa709e",
+      "debian-7.1.0": "ami-f1f064f0"
+    },
+    "ap-southeast-1": {
+      "ubuntu-10.04": "ami-34713866",
+      "ubuntu-12.04": "ami-881c57da",
+      "ubuntu-12.10": "ami-3ce0a86e",
+      "ubuntu-13.04": "ami-4af5bd18",
+      "centos-6.4": "ami-46f5bb14",
+      "debian-7.1.0": "ami-fe8ac3ac"
+    },
+    "ap-southeast-2": {
+      "ubuntu-10.04": "ami-2f009315",
+      "ubuntu-12.04": "ami-cb26b4f1",
+      "ubuntu-12.10": "ami-1703912d",
+      "ubuntu-13.04": "ami-8f32a0b5",
+      "centos-6.4": "ami-9352c1a9",
+      "debian-7.1.0": "ami-4e099a74"
+    },
+    "eu-west-1": {
+      "ubuntu-10.04": "ami-bbadb0cf",
+      "ubuntu-12.04": "ami-d3b5aea7",
+      "ubuntu-12.10": "ami-6b62791f",
+      "ubuntu-13.04": "ami-6fd4cf1b",
+      "centos-6.4": "ami-75190b01",
+      "debian-7.1.0": "ami-954559e1"
+    },
+    "sa-east-1": {
+      "ubuntu-10.04": "ami-962c898b",
+      "ubuntu-12.04": "ami-c905a1d4",
+      "ubuntu-12.10": "ami-e759fdfa",
+      "ubuntu-13.04": "ami-4b2b8f56",
+      "centos-6.4": "ami-a665c0bb",
+      "debian-7.1.0": "ami-b03590ad"
+    },
+    "us-east-1": {
+      "ubuntu-10.04": "ami-1ab3ce73",
+      "ubuntu-12.04": "ami-2f115c46",
+      "ubuntu-12.10": "ami-4d5b1824",
+      "ubuntu-13.04": "ami-a73371ce",
+      "centos-6.4": "ami-bf5021d6",
+      "debian-7.1.0": "ami-50d9a439"
+    },
+    "us-west-1": {
+      "ubuntu-10.04": "ami-848ba2c1",
+      "ubuntu-12.04": "ami-eaf0daaf",
+      "ubuntu-12.10": "ami-02220847",
+      "ubuntu-13.04": "ami-fe052fbb",
+      "centos-6.4": "ami-5d456c18",
+      "debian-7.1.0": "ami-1a9bb25f"
+    },
+    "us-west-2": {
+      "ubuntu-10.04": "ami-f19407c1",
+      "ubuntu-12.04": "ami-e6f36fd6",
+      "ubuntu-12.10": "ami-0c069b3c",
+      "ubuntu-13.04": "ami-4ade427a",
+      "centos-6.4": "ami-b3bf2f83",
+      "debian-7.1.0": "ami-158a1925"
+    }
+  },
+  "usernames": {
+    "ubuntu-10.04": "ubuntu",
+    "ubuntu-12.04": "ubuntu",
+    "ubuntu-12.10": "ubuntu",
+    "ubuntu-13.04": "ubuntu",
+    "centos-6.4": "root",
+    "debian-7.1.0": "admin"
+  },
+  "references": {
+    "ubuntu": "http://uec-images.ubuntu.com/query/",
+    "debian": "https://wiki.debian.org/Cloud/AmazonEC2Image",
+    "centos": "http://wiki.centos.org/Cloud/AWS"
+  }
+}

lib/kitchen/driver/ec2.rb

@@ -17,6 +17,7 @@
 # limitations under the License.
 
 require 'benchmark'
+require 'json'
 require 'fog'
 
 require 'kitchen'
@@ -35,7 +36,21 @@ class Ec2 < Kitchen::Driver::SSHBase
       default_config :flavor_id,          'm1.small'
       default_config :groups,             ['default']
       default_config :tags,               { 'created-by' => 'test-kitchen' }
-      default_config :username,           'root'
+      default_config :aws_access_key_id do |driver|
+        ENV['AWS_ACCESS_KEY']
+      end
+      default_config :aws_secret_access_key do |driver|
+        ENV['AWS_SECRET_KEY']
+      end
+      default_config :aws_ssh_key_id do |driver|
+        ENV['AWS_SSH_KEY_ID']
+      end
+      default_config :image_id do |driver|
+        driver.default_ami
+      end
+      default_config :username do |driver|
+        driver.default_username
+      end
 
       required_config :aws_access_key_id
       required_config :aws_secret_access_key
@@ -65,6 +80,15 @@ def destroy(state)
         state.delete(:hostname)
       end
 
+      def default_ami
+        region = amis["regions"][config[:region]]
+        region && region[instance.platform.name]
+      end
+
+      def default_username
+        amis["usernames"][instance.platform.name] || "root"
+      end
+
       private
 
       def connection
@@ -100,6 +124,14 @@ def debug_server_config
         debug("ec2:key_name '#{config[:aws_ssh_key_id]}'")
         debug("ec2:subnet_id '#{config[:subnet_id]}'")
       end
+
+      def amis
+        @amis ||= begin
+          json_file = File.join(File.dirname(__FILE__),
+            %w{.. .. .. data amis.json})
+          JSON.load(IO.read(json_file))
+        end
+      end
     end
   end
 end