Add thing delete command (#24)

Things can now be deleted with the following command:
$ iot-cloud-cli thing delete --device-id <deviceID>

* Add thing delete command

* Update readme

Author: polldo

Diff for: README.md

@@ -66,4 +66,8 @@ Print a *filtered* list of available things, print only things belonging to the
 
 Print only the thing associated to the passed device:
 
-`$ iot-cloud-cli thing list --device-id <deviceID>`
+`$ iot-cloud-cli thing list --device-id <deviceID>`
+
+Delete a thing with the following command:
+
+`$ iot-cloud-cli thing delete --device-id <deviceID>`

Diff for: cli/thing/delete.go

@@ -0,0 +1,37 @@
+package thing
+
+import (
+	"fmt"
+
+	"github.com/arduino/iot-cloud-cli/command/thing"
+	"github.com/spf13/cobra"
+)
+
+var deleteFlags struct {
+	id string
+}
+
+func initDeleteCommand() *cobra.Command {
+	deleteCommand := &cobra.Command{
+		Use:   "delete",
+		Short: "Delete a thing",
+		Long:  "Delete a thing from Arduino IoT Cloud",
+		RunE:  runDeleteCommand,
+	}
+	deleteCommand.Flags().StringVarP(&deleteFlags.id, "id", "i", "", "Thing ID")
+	deleteCommand.MarkFlagRequired("id")
+	return deleteCommand
+}
+
+func runDeleteCommand(cmd *cobra.Command, args []string) error {
+	fmt.Printf("Deleting thing %s\n", deleteFlags.id)
+
+	params := &thing.DeleteParams{ID: deleteFlags.id}
+	err := thing.Delete(params)
+	if err != nil {
+		return err
+	}
+
+	fmt.Println("Thing successfully deleted")
+	return nil
+}

Diff for: cli/thing/thing.go

@@ -13,6 +13,7 @@ func NewCommand() *cobra.Command {
 
 	thingCommand.AddCommand(initCreateCommand())
 	thingCommand.AddCommand(initListCommand())
+	thingCommand.AddCommand(initDeleteCommand())
 
 	return thingCommand
 }

Diff for: command/thing/delete.go

@@ -0,0 +1,27 @@
+package thing
+
+import (
+	"github.com/arduino/iot-cloud-cli/internal/config"
+	"github.com/arduino/iot-cloud-cli/internal/iot"
+)
+
+// DeleteParams contains the parameters needed to
+// delete a thing from Arduino IoT Cloud.
+type DeleteParams struct {
+	ID string
+}
+
+// Delete command is used to delete a thing
+// from Arduino IoT Cloud.
+func Delete(params *DeleteParams) error {
+	conf, err := config.Retrieve()
+	if err != nil {
+		return err
+	}
+	iotClient, err := iot.NewClient(conf.Client, conf.Secret)
+	if err != nil {
+		return err
+	}
+
+	return iotClient.DeleteThing(params.ID)
+}

Diff for: internal/iot/client.go

@@ -16,6 +16,7 @@ type Client interface {
 	ListDevices() ([]iotclient.ArduinoDevicev2, error)
 	AddCertificate(id, csr string) (*iotclient.ArduinoCompressedv2, error)
 	AddThing(thing *iotclient.Thing, force bool) (string, error)
+	DeleteThing(id string) error
 	GetThing(id string) (*iotclient.ArduinoThing, error)
 	ListThings(ids []string, device *string, props bool) ([]iotclient.ArduinoThing, error)
 }
@@ -107,6 +108,16 @@ func (cl *client) AddThing(thing *iotclient.Thing, force bool) (string, error) {
 	return newThing.Id, nil
 }
 
+// DeleteThing deletes a thing from Arduino IoT Cloud.
+func (cl *client) DeleteThing(id string) error {
+	_, err := cl.api.ThingsV2Api.ThingsV2Delete(cl.ctx, id, nil)
+	if err != nil {
+		err = fmt.Errorf("deleting thing: %w", err)
+		return err
+	}
+	return nil
+}
+
 // GetThing allows to retrieve a specific thing, given its id,
 // from Arduino IoT Cloud.
 func (cl *client) GetThing(id string) (*iotclient.ArduinoThing, error) {