Added fixer for ssh_key_path

- ssh_key_path is removed in all cases.
- The new fixer is not checking the builder type so it will execute for all
  builders.
- If ssh_key_path exists without ssh_private_key_file then it will assign
  the value of ssh_path_path to ssh_private_key_file
- If ssh_private_key_file and ssh_key_path exist, then ssh_key_path is
  simply removed

I wanted to emit a warning messsage to the user but it didn't seem like
the ui.* interface was exposed to fixers.

fix/fixer.go

@@ -28,6 +28,7 @@ func init() {
 		"vmware-rename":          new(FixerVMwareRename),
 		"parallels-headless":     new(FixerParallelsHeadless),
 		"parallels-deprecations": new(FixerParallelsDeprecations),
+		"sshkeypath":             new(FixerSSHKeyPath),
 	}
 
 	FixerOrder = []string{
@@ -39,5 +40,6 @@ func init() {
 		"vmware-rename",
 		"parallels-headless",
 		"parallels-deprecations",
+		"sshkeypath",
 	}
 }

fix/fixer_sshkeypath.go

@@ -0,0 +1,50 @@
+package fix
+
+import (
+	"github.com/mitchellh/mapstructure"
+)
+
+// FixerSSHKeyPath changes the "ssh_key_path" of a template
+// to "ssh_private_key_file".
+type FixerSSHKeyPath struct{}
+
+func (FixerSSHKeyPath) Fix(input map[string]interface{}) (map[string]interface{}, error) {
+	// The type we'll decode into; we only care about builders
+	type template struct {
+		Builders []map[string]interface{}
+	}
+
+	// Decode the input into our structure, if we can
+	var tpl template
+	if err := mapstructure.Decode(input, &tpl); err != nil {
+		return nil, err
+	}
+
+	for _, builder := range tpl.Builders {
+		sshKeyPathRaw, ok := builder["ssh_key_path"]
+		if !ok {
+			continue
+		}
+
+		sshKeyPath, ok := sshKeyPathRaw.(string)
+		if !ok {
+			continue
+		}
+
+		// only assign to ssh_private_key_file if it doesn't
+		// already exist; otherwise we'll just ignore ssh_key_path
+		_, sshPrivateIncluded := builder["ssh_private_key_file"]
+		if !sshPrivateIncluded {
+			builder["ssh_private_key_file"] = sshKeyPath
+		}
+
+		delete(builder, "ssh_key_path")
+	}
+
+	input["builders"] = tpl.Builders
+	return input, nil
+}
+
+func (FixerSSHKeyPath) Synopsis() string {
+	return `Updates builders using "ssh_key_path" to use "ssh_private_key_file"`
+}

fix/fixer_sshkeypath_test.go

@@ -0,0 +1,83 @@
+package fix
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFixerSSHKeyPath_Impl(t *testing.T) {
+	var _ Fixer = new(FixerSSHKeyPath)
+}
+
+func TestFixerSSHKeyPath_Fix(t *testing.T) {
+	cases := []struct {
+		Input    map[string]interface{}
+		Expected map[string]interface{}
+	}{
+		// No key_path field
+		{
+			Input: map[string]interface{}{
+				"type": "virtualbox",
+			},
+
+			Expected: map[string]interface{}{
+				"type": "virtualbox",
+			},
+		},
+
+		// private_key_file without key_path
+		{
+			Input: map[string]interface{}{
+				"ssh_private_key_file": "id_rsa",
+			},
+
+			Expected: map[string]interface{}{
+				"ssh_private_key_file": "id_rsa",
+			},
+		},
+
+		// key_path without private_key_file
+		{
+			Input: map[string]interface{}{
+				"ssh_key_path": "id_rsa",
+			},
+
+			Expected: map[string]interface{}{
+				"ssh_private_key_file": "id_rsa",
+			},
+		},
+
+		// key_path and private_key_file
+		{
+			Input: map[string]interface{}{
+				"ssh_key_path":         "key_id_rsa",
+				"ssh_private_key_file": "private_id_rsa",
+			},
+
+			Expected: map[string]interface{}{
+				"ssh_private_key_file": "private_id_rsa",
+			},
+		},
+	}
+
+	for _, tc := range cases {
+		var f FixerSSHKeyPath
+
+		input := map[string]interface{}{
+			"builders": []map[string]interface{}{tc.Input},
+		}
+
+		expected := map[string]interface{}{
+			"builders": []map[string]interface{}{tc.Expected},
+		}
+
+		output, err := f.Fix(input)
+		if err != nil {
+			t.Fatalf("err: %s", err)
+		}
+
+		if !reflect.DeepEqual(output, expected) {
+			t.Fatalf("unexpected: %#v\nexpected: %#v\n", output, expected)
+		}
+	}
+}