decode Options using DecodeMapstructure

Signed-off-by: Nicolas De Loof <[email protected]>

Author: ndeloof

loader/loader.go

@@ -607,7 +607,7 @@ type Transformer struct {
 func createTransformHook(additionalTransformers ...Transformer) mapstructure.DecodeHookFuncType {
 	transforms := map[reflect.Type]func(interface{}) (interface{}, error){
 		reflect.TypeOf(types.External{}):                         transformExternal,
-		reflect.TypeOf(types.Options{}):                      transformMapStringString,
+		reflect.TypeOf(types.Options{}):                          transformOptions,
 		reflect.TypeOf(types.UlimitsConfig{}):                    transformUlimits,
 		reflect.TypeOf([]types.ServicePortConfig{}):              transformServicePort,
 		reflect.TypeOf(types.ServiceSecretConfig{}):              transformFileReferenceConfig,
@@ -1020,7 +1020,7 @@ func loadFileObjectConfig(name string, objType string, obj types.FileObjectConfi
 	return obj, nil
 }
 
-var transformMapStringString TransformerFunc = func(data interface{}) (interface{}, error) {
+var transformOptions TransformerFunc = func(data interface{}) (interface{}, error) {
 	switch value := data.(type) {
 	case map[string]interface{}:
 		return toMapStringString(value, false), nil

types/options.go

@@ -0,0 +1,46 @@
+/*
+   Copyright 2020 The Compose Specification Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package types
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+)
+
+// Options is a mapping type for options we pass as-is to container runtime
+type Options map[string]string
+
+func (d *Options) DecodeMapstructure(value interface{}) error {
+	switch v := value.(type) {
+	case map[string]interface{}:
+		m := make(map[string]string)
+		for key, e := range v {
+			if e == nil {
+				m[key] = ""
+			} else {
+				m[key] = fmt.Sprint(e)
+			}
+		}
+		*d = m
+	case map[string]string:
+		*d = v
+	default:
+		return errors.Errorf("invalid type %T for options", value)
+	}
+	return nil
+}

types/types.go

@@ -442,9 +442,6 @@ func (m Mapping) Merge(o Mapping) Mapping {
 	return m
 }
 
-// Options is a mapping type for options we pass as-is to container runtime
-type Options map[string]string
-
 type SSHKey struct {
 	ID   string
 	Path string