command: autoload terraform.tfvars.json as well [GH-1030]

command/apply_test.go

@@ -960,6 +960,58 @@ func TestApply_varFileDefault(t *testing.T) {
 	}
 }
 
+func TestApply_varFileDefaultJSON(t *testing.T) {
+	varFileDir := testTempDir(t)
+	varFilePath := filepath.Join(varFileDir, "terraform.tfvars.json")
+	if err := ioutil.WriteFile(varFilePath, []byte(applyVarFileJSON), 0644); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	statePath := testTempFile(t)
+
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	if err := os.Chdir(varFileDir); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer os.Chdir(cwd)
+
+	p := testProvider()
+	ui := new(cli.MockUi)
+	c := &ApplyCommand{
+		Meta: Meta{
+			ContextOpts: testCtxConfig(p),
+			Ui:          ui,
+		},
+	}
+
+	actual := ""
+	p.DiffFn = func(
+		info *terraform.InstanceInfo,
+		s *terraform.InstanceState,
+		c *terraform.ResourceConfig) (*terraform.InstanceDiff, error) {
+		if v, ok := c.Config["value"]; ok {
+			actual = v.(string)
+		}
+
+		return &terraform.InstanceDiff{}, nil
+	}
+
+	args := []string{
+		"-state", statePath,
+		testFixturePath("apply-vars"),
+	}
+	if code := c.Run(args); code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, ui.ErrorWriter.String())
+	}
+
+	if actual != "bar" {
+		t.Fatal("didn't work")
+	}
+}
+
 func TestApply_backup(t *testing.T) {
 	originalState := &terraform.State{
 		Modules: []*terraform.ModuleState{
@@ -1150,6 +1202,10 @@ const applyVarFile = `
 foo = "bar"
 `
 
+const applyVarFileJSON = `
+{ "foo": "bar" }
+`
+
 const testApplyDisableBackupStr = `
 ID = bar
 `

command/meta.go

@@ -346,6 +346,14 @@ func (m *Meta) process(args []string, vars bool) []string {
 			args[0] = "-" + m.autoKey
 			args[1] = DefaultVarsFilename
 		}
+
+		if _, err := os.Stat(DefaultVarsFilename + ".json"); err == nil {
+			m.autoKey = "var-file-default"
+			args = append(args, "", "")
+			copy(args[2:], args[0:])
+			args[0] = "-" + m.autoKey
+			args[1] = DefaultVarsFilename + ".json"
+		}
 	}
 
 	return args