builder/vmware: delete unnecessary files from artifact

CHANGELOG.md

 ## 0.1.2 (unreleased)
 
+IMPROVEMENTS:
+
+* vmware: Delete any VMware files in the VM that aren't necessary for
+  it to function.
+
 BUG FIXES:
 
 * amazon-ebs: Sleep between checking instance state to avoid

builder/vmware/builder.go

@@ -224,6 +224,7 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 		&stepWaitForSSH{},
 		&stepProvision{},
 		&stepShutdown{},
+		&stepCleanFiles{},
 	}
 
 	// Setup the state bag
@@ -263,11 +264,15 @@ func (b *Builder) Run(ui packer.Ui, hook packer.Hook, cache packer.Cache) (packe
 	// Compile the artifact list
 	files := make([]string, 0, 10)
 	visit := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
 		if !info.IsDir() {
 			files = append(files, path)
 		}
 
-		return err
+		return nil
 	}
 
 	if err := filepath.Walk(b.config.OutputDir, visit); err != nil {

builder/vmware/step_clean_files.go

+package vmware
+
+import (
+	"fmt"
+	"github.com/mitchellh/multistep"
+	"github.com/mitchellh/packer/packer"
+	"os"
+	"path/filepath"
+)
+
+// These are the extensions of files that are important for the function
+// of a VMware virtual machine. Any other file is discarded as part of the
+// build.
+var KeepFileExtensions = []string{".nvram", ".vmdk", ".vmsd", ".vmx", ".vmxf"}
+
+// This step removes unnecessary files from the final result.
+//
+// Uses:
+//   config *config
+//   ui     packer.Ui
+//
+// Produces:
+//   <nothing>
+type stepCleanFiles struct{}
+
+func (stepCleanFiles) Run(state map[string]interface{}) multistep.StepAction {
+	config := state["config"].(*config)
+	ui := state["ui"].(packer.Ui)
+
+	ui.Say("Deleting unnecessary VMware files...")
+	visit := func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		if !info.IsDir() {
+			// If the file isn't critical to the function of the
+			// virtual machine, we get rid of it.
+			keep := false
+			ext := filepath.Ext(path)
+			for _, goodExt := range KeepFileExtensions {
+				if goodExt == ext {
+					keep = true
+					break
+				}
+			}
+
+			if !keep {
+				ui.Message(fmt.Sprintf("Deleting: %s", path))
+				return os.Remove(path)
+			}
+		}
+
+		return nil
+	}
+
+	if err := filepath.Walk(config.OutputDir, visit); err != nil {
+		state["error"] = err
+		return multistep.ActionHalt
+	}
+
+	return multistep.ActionContinue
+}
+
+func (stepCleanFiles) Cleanup(map[string]interface{}) {}