File atomic update default: false on docker files

If unspecified, the default setting for atomic updates on docker special
files should be 'false' to avoid Errno::EBUSY.  This allows for a cookbook
author to override this behaviour if desired.

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/chef/dsl/platform_introspection.rb b/lib/chef/dsl/platform_introspection.rb
index 276a03af63..679b702383 100644
--- a/lib/chef/dsl/platform_introspection.rb
+++ b/lib/chef/dsl/platform_introspection.rb
@@ -245,6 +245,19 @@ class Chef
         end
       end
 
+      # Shamelessly stolen from https://github.com/sethvargo/chef-sugar/blob/master/lib/chef/sugar/docker.rb
+      # Given a node object, returns whether the node is a docker container.
+      #
+      # === Parameters
+      # node:: [Chef::Node] The node to check.
+      #
+      # === Returns
+      # true:: if the current node is a docker container
+      # false:: if the current node is not a docker container
+      def docker?(node)
+        ::File.exist?('/.dockerinit') || ::File.exist?('/.dockerenv')
+      end
+
     end
   end
 end