Add output flag for writing chart files

Signed-off-by: aiordache <anca.iordache@docker.com>

cli/cmd/compose/convert.go

@@ -30,8 +30,11 @@ import (
 type convertOptions struct {
 	*projectOptions
 	Format string
+	Output string
 }
 
+var addFlagsFuncs []func(cmd *cobra.Command, opts *convertOptions)
+
 func convertCommand(p *projectOptions) *cobra.Command {
 	opts := convertOptions{
 		projectOptions: p,
@@ -47,6 +50,10 @@ func convertCommand(p *projectOptions) *cobra.Command {
 	flags := convertCmd.Flags()
 	flags.StringVar(&opts.Format, "format", "yaml", "Format the output. Values: [yaml | json]")
 
+	// add flags for hidden backends
+	for _, f := range addFlagsFuncs {
+		f(convertCmd, &opts)
+	}
 	return convertCmd
 }
 
@@ -64,11 +71,14 @@ func runConvert(ctx context.Context, opts convertOptions, services []string) err
 
 	json, err = c.ComposeService().Convert(ctx, project, compose.ConvertOptions{
 		Format: opts.Format,
+		Output: opts.Output,
 	})
 	if err != nil {
 		return err
 	}
-
+	if opts.Output != "" {
+		fmt.Print("model saved to ")
+	}
 	fmt.Println(string(json))
 	return nil
 }

cli/cmd/compose/convert_kube.go

@@ -0,0 +1,31 @@
+// +build kube
+
+/*
+   Copyright 2020 Docker Compose CLI 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 compose
+
+import (
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	addFlagsFuncs = append(addFlagsFuncs, func(cmd *cobra.Command, opts *convertOptions) {
+		flags := cmd.Flags()
+		flags.StringVar(&opts.Output, "output", "", "Save to directory")
+	})
+
+}