Switch to node attributes for docker detection

Using ::File.exists? makes Travis CI sad due to statically looking for
files.  We'll use node attributes provided by Ohai instead.

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/chef/dsl/platform_introspection.rb b/lib/chef/dsl/platform_introspection.rb
index 4ccdb34981..a0c2d33967 100644
--- a/lib/chef/dsl/platform_introspection.rb
+++ b/lib/chef/dsl/platform_introspection.rb
@@ -254,8 +254,11 @@ class Chef
       # === 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")
+      def docker?(node = run_context.nil? ? nil : run_context.node)
+        # Using "File.exist?('/.dockerinit') || File.exist?('/.dockerenv')" makes Travis sad,
+        # and that makes us sad too.
+        node && node[:virtualization] && node[:virtualization][:systems] &&
+          node[:virtualization][:systems][:docker] && node[:virtualization][:systems][:docker] == "guest"
       end
 
     end