Feature: look up snapshot ids by region from chef config data.

Squashed commit of the following:

commit 960d7abba089d9046bf567b434ed126bd66221c3
Author: Chris Howe <howech@infochimps.com>
Date:   Wed May 28 17:01:59 2014 -0500

    When building a machine, lookup the snapshot name in chef config data so that we can associate a different snapshot with each name by region.

    Change-Id: Id12fcff2e9c1b3d88e571a47b5454c3b3cbd0ed5

commit 2b1ed75634ab6c134c73ea287147e293c97a7f70
Author: Chris Howe <howech@infochimps.com>
Date:   Wed May 28 17:01:03 2014 -0500

    Added an error message to the "mismatched regions" error that allows you to know which setting is wrong.

    Change-Id: I681ef1e59984798bc95acce2f8a4940c2236dffe

commit ca0afc982125ba5aa30fec0c3f459aae195f0ca0
Author: Chris Howe <howech@infochimps.com>
Date:   Wed May 28 17:00:33 2014 -0500

    removed crufty VOLUME_IDS lookup for snashot_id

    Change-Id: I01621d6d94bc3d373e333e0e134b8a12100a6a9c

Change-Id: I1a4d6e91c3d5ce81dc359490b02711bed8291ae1

lib/ironfan/broker/computer.rb

@@ -13,14 +13,29 @@ class Computer < Builder
       field :name,              String
       field :bogus,             Array,  :default => []
 
+      def lookup_snapshot_id(region, snapshot_name) 
+        keys = [region.to_s, snapshot_name.to_s]
+        return Chef::Config[:ec2_snapshot_info][ keys ][:snapshot_id] rescue nil
+      end
+
       def initialize(*args)
         super
         providers[:chef] ||=    Ironfan::Provider::ChefServer
         return unless server
         providers[:iaas]   = server.selected_cloud.provider
         volumes            = server.volumes.values
+        puts server.selected_cloud
+        region = server.selected_cloud.region
+
+
+        # Turn snapshot names into snapshot ids corresponding to the server region
+        volumes.each do |vol|
+          vol.snapshot_id || vol.snapshot_id(lookup_snapshot_id(region, vol.snapshot_name))
+        end
+
         volumes           += server.implied_volumes
         volumes.each{|vol| self.drive vol.name, :volume => vol }
+
       rescue StandardError => err ; err.polish("#{self.class} on '#{args.inspect}'") rescue nil ; raise
       end
 
@@ -365,7 +380,7 @@ def slice(cluster_name = nil, facet_name = nil, slice_indexes = nil)
         select do |mach|
           mach.bogus? || (
             # facet match, and index match (or no indexes specified)
-            (mach.server.cluster_name == cluster_name) &&                          
+            (mach.server.cluster_name == cluster_name) &&
             (mach.server.facet_name == facet_name || facet_name.nil?) &&
             (slice_array.include?(mach.server.index) || slice_indexes.nil?))
         end

lib/ironfan/dsl/volume.rb

@@ -24,17 +24,6 @@ class Volume < Ironfan::Dsl
       magic     :snapshot_name,         String
       magic     :tags,                  Hash,     :default => {}
 
-      VOLUME_IDS ||= {}
-      VOLUME_IDS.merge!({
-                            :blank_xfs             => 'snap-d9c1edb1',
-                            :blank_xfs_tokyo       => 'snap-049d1921',
-                            :blank_xfs_california  => 'snap-514b5c5a', # us-west-1
-                        })
-
-      def snapshot_id(*)
-        Ironfan.todo("CODE SMELL: EBS specific information in Dsl::Volume::VOLUME_IDS")
-        super || VOLUME_IDS[snapshot_name]
-      end
     end
 
     class RaidGroup < Volume

lib/ironfan/provider/ec2/machine.rb

@@ -226,8 +226,13 @@ def self.lint(computer)
           errors['Missing client']      = info            unless computer.client?
           errors['Missing private_key'] = computer.client unless computer.private_key
           #
-          all_asserted_regions = [Ec2.connection.region, cloud.region, Chef::Config[:knife][:region], Ironfan.chef_config[:region]].compact.uniq
-          errors["mismatched region"] = all_asserted_regions unless all_asserted_regions.count == 1
+          asserted_regions = {
+            :ec2_connection => Ec2.connection.region,
+            :cloud => cloud.region,
+            :knife => Chef::Config[:knife][:region],
+            :chef_config => Ironfan.chef_config[:region]
+          }
+          errors["mismatched region"] = asserted_regions unless asserted_regions.values.compact.uniq.count == 1
           #
           errors
         end