raise an error if trying to re-save a model

lib/fog/aws/models/compute/address.rb

@@ -32,6 +32,7 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           data = connection.allocate_address
           @public_ip = data.body['publicIp']
           if @server

lib/fog/aws/models/compute/server.rb

@@ -125,6 +125,7 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :image_id
 
           options = {

lib/fog/aws/models/compute/snapshot.rb

@@ -30,6 +30,7 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :volume_id
 
           data = connection.create_snapshot(@volume_id, @description).body

lib/fog/aws/models/compute/volume.rb

@@ -36,15 +36,8 @@ module Fog
           state == 'available'
         end
 
-        def server=(new_server)
-          if new_server
-            attach(new_server)
-          else
-            detach
-          end
-        end
-
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :availability_zone, :size
 
           data = connection.create_volume(@availability_zone, @size, @snapshot_id).body
@@ -56,6 +49,14 @@ module Fog
           true
         end
 
+        def server=(new_server)
+          if new_server
+            attach(new_server)
+          else
+            detach
+          end
+        end
+
         def snapshots
           requires :id
 

lib/fog/bluebox/models/compute/server.rb

@@ -76,6 +76,7 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :flavor_id, :image_id
           options = if !password && !public_key
             raise(ArgumentError, "password or public_key is required for this operation")

lib/fog/rackspace/models/compute/image.rb

@@ -33,6 +33,7 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :server_id
 
           data = connection.create_image(@server_id, 'name' => name)

lib/fog/rackspace/models/compute/server.rb

@@ -47,16 +47,6 @@ module Fog
           connection.images(:server => self)
         end
 
-        def ready?
-          @status == 'ACTIVE'
-        end
-
-        def reboot(type = 'SOFT')
-          requires :id
-          connection.reboot_server(@id, type)
-          true
-        end
-
         def private_key_path
           File.expand_path(@private_key_path ||= Fog.credentials[:private_key_path])
         end
@@ -73,7 +63,18 @@ module Fog
           @public_key ||= File.read(public_key_path)
         end
 
+        def ready?
+          @status == 'ACTIVE'
+        end
+
+        def reboot(type = 'SOFT')
+          requires :id
+          connection.reboot_server(@id, type)
+          true
+        end
+
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :flavor_id, :image_id, :name
           options = {
             'metadata'    => @metadata,

lib/fog/slicehost/models/compute/server.rb

@@ -70,7 +70,9 @@ module Fog
         end
 
         def save
+          raise Fog::Errors::Error.new('Resaving an existing object may create a duplicate') if identity
           requires :flavor_id, :image_id, :name
+
           data = connection.create_slice(@flavor_id, @image_id, @name)
           merge_attributes(data.body)
           true