add appGUID to droplet resource (#2933)

Author: gmllt

Diff for: resources/droplet_resource.go

@@ -1,12 +1,17 @@
 package resources
 
 import (
+	"encoding/json"
+
+	"code.cloudfoundry.org/cli/api/cloudcontroller"
 	"code.cloudfoundry.org/cli/api/cloudcontroller/ccv3/constant"
 )
 
 // Droplet represents a Cloud Controller droplet's metadata. A droplet is a set of
 // compiled bits for a given application.
 type Droplet struct {
+	// AppGUID is the unique identifier of the application associated with the droplet.
+	AppGUID string `json:"app_guid"`
 	//Buildpacks are the detected buildpacks from the staging process.
 	Buildpacks []DropletBuildpack `json:"buildpacks,omitempty"`
 	// CreatedAt is the timestamp that the Cloud Controller created the droplet.
@@ -35,3 +40,87 @@ type DropletBuildpack struct {
 	// Version is the version of the detected buildpack.
 	Version string `json:"version"`
 }
+
+func (d Droplet) MarshallJSON() ([]byte, error) {
+	type ccDroplet struct {
+		GUID          string                `json:"guid,omitempty"`
+		Buildpacks    []DropletBuildpack    `json:"buildpacks,omitempty"`
+		CreatedAt     string                `json:"created_at,omitempty"`
+		Image         string                `json:"image,omitempty"`
+		Stack         string                `json:"stack,omitempty"`
+		State         constant.DropletState `json:"state,omitempty"`
+		Relationships *struct {
+			App struct {
+				Data struct {
+					GUID string `json:"guid,omitempty"`
+				} `json:"data,omitempty"`
+			} `json:"app,omitempty"`
+		} `json:"relationships,omitempty"`
+	}
+
+	ccD := ccDroplet{
+		GUID:       d.GUID,
+		Buildpacks: d.Buildpacks,
+		CreatedAt:  d.CreatedAt,
+		Image:      d.Image,
+		Stack:      d.Stack,
+		State:      d.State,
+	}
+
+	if d.AppGUID != "" {
+		ccD.Relationships = &struct {
+			App struct {
+				Data struct {
+					GUID string `json:"guid,omitempty"`
+				} `json:"data,omitempty"`
+			} `json:"app,omitempty"`
+		}{
+			App: struct {
+				Data struct {
+					GUID string `json:"guid,omitempty"`
+				} `json:"data,omitempty"`
+			}{
+				Data: struct {
+					GUID string `json:"guid,omitempty"`
+				}{
+					GUID: d.AppGUID,
+				},
+			},
+		}
+	}
+
+	return json.Marshal(ccD)
+}
+
+func (d *Droplet) UnmarshalJSON(data []byte) error {
+	var alias struct {
+		GUID          string                `json:"guid,omitempty"`
+		Buildpacks    []DropletBuildpack    `json:"buildpacks,omitempty"`
+		CreatedAt     string                `json:"created_at,omitempty"`
+		Image         string                `json:"image,omitempty"`
+		Stack         string                `json:"stack,omitempty"`
+		State         constant.DropletState `json:"state,omitempty"`
+		Relationships struct {
+			App struct {
+				Data struct {
+					GUID string `json:"guid,omitempty"`
+				} `json:"data,omitempty"`
+			} `json:"app,omitempty"`
+		}
+	}
+
+	err := cloudcontroller.DecodeJSON(data, &alias)
+	if err != nil {
+		return err
+	}
+
+	d.GUID = alias.GUID
+	d.Buildpacks = alias.Buildpacks
+	d.CreatedAt = alias.CreatedAt
+	d.Image = alias.Image
+	d.Stack = alias.Stack
+	d.State = alias.State
+	d.AppGUID = alias.Relationships.App.Data.GUID
+
+	return nil
+}