feat(plan): allow build plan to be output as YAML or JSON

pkg/plan/plan.go

@@ -2,6 +2,7 @@ package plan
 
 import (
 	"bytes"
+	"encoding/json"
 	"io"
 	"os"
 
@@ -11,11 +12,11 @@ import (
 )
 
 type Plan struct {
-	Build   *Build         `yaml:"build,omitempty"`
-	Source  *source.Source `yaml:"source,omitempty"`
-	OS      *osinfo.OSInfo `yaml:"os,omitempty"`
-	Release *Release       `yaml:"release,omitempty"`
-	Output  *Output        `yaml:"output,omitempty"`
+	Build   *Build         `yaml:"build,omitempty" json:"build,omitempty"`
+	Source  *source.Source `yaml:"source,omitempty" json:"source,omitempty"`
+	OS      *osinfo.OSInfo `yaml:"os,omitempty" json:"os,omitempty"`
+	Release *Release       `yaml:"release,omitempty" json:"release,omitempty"`
+	Output  *Output        `yaml:"output,omitempty" json:"output,omitempty"`
 }
 
 // Load attempts to loads a plan YAML from given filename.
@@ -53,18 +54,37 @@ func (s *Plan) YAML() (string, error) {
 	return buf.String(), nil
 }
 
+// WriteJSON writes plan in JSON format to given io.Writer.
+func (s *Plan) WriteJSON(w io.Writer) error {
+	enc := json.NewEncoder(w)
+	enc.SetIndent("", "  ")
+
+	return enc.Encode(s)
+}
+
+// JSON returns plan in JSON format.
+func (s *Plan) JSON() (string, error) {
+	var buf bytes.Buffer
+	err := s.WriteJSON(&buf)
+	if err != nil {
+		return "", err
+	}
+
+	return buf.String(), nil
+}
+
 type Build struct {
-	Name string `yaml:"name,omitempty"`
+	Name string `yaml:"name,omitempty" json:"name,omitempty"`
 }
 
 type Release struct {
-	Name       string `yaml:"name"`
-	Title      string `yaml:"title,omitempty"`
-	Draft      bool   `yaml:"draft,omitempty"`
-	Prerelease bool   `yaml:"prerelease,omitempty"`
+	Name       string `yaml:"name" json:"name"`
+	Title      string `yaml:"title,omitempty" json:"title,omitempty"`
+	Draft      bool   `yaml:"draft,omitempty" json:"draft,omitempty"`
+	Prerelease bool   `yaml:"prerelease,omitempty" json:"prerelease,omitempty"`
 }
 
 type Output struct {
-	Directory string `yaml:"directory,omitempty"`
-	DiskImage string `yaml:"disk_image,omitempty"`
+	Directory string `yaml:"directory,omitempty" json:"directory,omitempty"`
+	DiskImage string `yaml:"disk_image,omitempty" json:"disk_image,omitempty"`
 }