Add device list command (#21)

This PR introduces the device list command, useful to retrieve devices of arduino iot cloud.
To list devices, no flags or arguments are needed, the command is simply:
$ iot-cloud-cli device list

maybe worth doing in the future:

    list command could accept a list of IDs that should be retrieved from the cloud
    edit: a new show command might be better

commits log:
* Add device list command

* Add comments

* Update readme

Author: polldo

Diff for: README.md

@@ -1,18 +1,13 @@
 # iot-cloud-cli
 
-iot-cloud-cli is a command line interface that allows to exploit the features of Arduino IoT Cloud. As of now, it is possible to provision a device and to simulate a device to be connected to the cloud using MQTT for troubleshooting purposes.
+iot-cloud-cli is a command line interface that allows to exploit the features of Arduino IoT Cloud. As of now, it is possible to provision a device.
 
 ### Requirements
 
 This is all you need to use iot-cloud-cli for device **provisioning**:
  * A client ID and a secret ID, retrievable from the [cloud](https://create.arduino.cc/iot/integrations) by creating a new API key
  * The folder containing the precompiled provisioning firmwares (`binaries`) needs to be in the same location you run the command from
 
-This is all you need to use iot-cloud-cli as a **virtual device**:
- * A "Generic ESP8266 Module" or "Generic ESP32 Module" device in IoT Cloud (requires a Maker plan)
- * A thing with a `counter` property connected to the "Generic ESP8266/ESP32 Module" device 
-
-
 ## Set a configuration
 
 iot-cloud-cli needs to be configured before being used. In particular a client ID and the corresponding secret ID should be set.
@@ -38,64 +33,7 @@ Use this command to provision a device:
 
 `$ iot-cloud-cli device create --name <deviceName> --port <port> --fqbn <deviceFqbn>`
 
+## Device commands
 
-## Use iot-cloud-cli as a virtual device
-
-The iot-cloud-cli can be used as a virtual device for Arduino IoT Cloud for testing.
-
-```
-$ iot-cloud-cli ping -u "<deviceId>" -p "<secret>" -t <thing ID>>
-  Connected to Arduino IoT Cloud
-  Subscribed true
-  Property value sent successfully 81
-  Property value sent successfully 87
-```
-
-### How to set up the device and thing in IoT Cloud
-
-#### Device
-
- * Visit https://create.arduino.cc/iot/devices and select "Add device".
- * Select "Set up a 3rd party device".
- * Select "ESP8266". 
- * From the drop down select "Generic ESP8266 Module", and click "Continue".
- * Pick a nice and friendly device name.
- * Save the "Device ID" and "Secret Key" in a safe place (1Password, KeepassXC, a piece of paper in your vault) , because you will not be able to see them anymore.
-  
-#### Thing ID
-
- * Visit https://create.arduino.cc/iot/things and select "Create Thing".
- * Select "Add Variable".
- * Give the variable the name "counter", type "Integer Number" and leave the variable permission the value "Read & Write".
- * Press the "Add Variable" button to confirm.
- * Copy the "Thing ID" from the bottom right of the page.
- 
-#### Connect the device and the thing
-
-You should connect the new device to the new thing.
-
-#### Testing
-
-##### Connect to the PROD environment
-
-```shell
-$ iot-cloud-cli ping -u "<Device ID>" -p "<Secret Key>" -t <Thing ID>>
-```
-
-If every works as expected you should see something similar to this output:
-```
-Connected to Arduino IoT Cloud
-Subscribed true
-Property value sent successfully 81
-Property value sent successfully 87
-```
-
-If you visit https://create.arduino.cc/iot/devices the "Generic ESP8266 Module" device status should be "Online".
-
-##### Connect to the DEV environment
-
-The DEV environment is using a different broker, so you need to add the option `--host`:
-
-```shell
-$ iot-cloud-cli ping --host tcps://mqtts-sa.iot.oniudra.cc:8884 -u "<Device ID>" -p "<Secret Key>" -t "<thing-id>"
-```
+Devices currently present on Arduino IoT Cloud can be retrieved by using this command:
+`$ iot-cloud-cli device list`

Diff for: cli/device/device.go

@@ -12,6 +12,7 @@ func NewCommand() *cobra.Command {
 	}
 
 	deviceCommand.AddCommand(initCreateCommand())
+	deviceCommand.AddCommand(initListCommand())
 
 	return deviceCommand
 }

Diff for: cli/device/list.go

@@ -0,0 +1,59 @@
+package device
+
+import (
+	"fmt"
+
+	"github.com/arduino/arduino-cli/cli/feedback"
+	"github.com/arduino/arduino-cli/table"
+	"github.com/arduino/iot-cloud-cli/command/device"
+	"github.com/spf13/cobra"
+)
+
+func initListCommand() *cobra.Command {
+	listCommand := &cobra.Command{
+		Use:   "list",
+		Short: "List devices",
+		Long:  "List devices on Arduino IoT Cloud",
+		RunE:  runListCommand,
+	}
+	return listCommand
+}
+
+func runListCommand(cmd *cobra.Command, args []string) error {
+	fmt.Println("Listing devices")
+
+	devs, err := device.List()
+	if err != nil {
+		return err
+	}
+
+	feedback.PrintResult(result{devs})
+
+	return nil
+}
+
+type result struct {
+	devices []device.DeviceInfo
+}
+
+func (r result) Data() interface{} {
+	return r.devices
+}
+
+func (r result) String() string {
+	if len(r.devices) == 0 {
+		return "No devices found."
+	}
+	t := table.New()
+	t.SetHeader("Name", "ID", "Board", "FQBN", "SerialNumber")
+	for _, device := range r.devices {
+		t.AddRow(
+			device.Name,
+			device.ID,
+			device.Board,
+			device.FQBN,
+			device.Serial,
+		)
+	}
+	return t.Render()
+}

Diff for: command/device/list.go

@@ -0,0 +1,48 @@
+package device
+
+import (
+	"github.com/arduino/iot-cloud-cli/internal/config"
+	"github.com/arduino/iot-cloud-cli/internal/iot"
+)
+
+// DeviceInfo contains the most interesting
+// parameters of an Arduino IoT Cloud device.
+type DeviceInfo struct {
+	Name   string
+	ID     string
+	Board  string
+	Serial string
+	FQBN   string
+}
+
+// List command is used to list
+// the devices of Arduino IoT Cloud.
+func List() ([]DeviceInfo, error) {
+	conf, err := config.Retrieve()
+	if err != nil {
+		return nil, err
+	}
+	iotClient, err := iot.NewClient(conf.Client, conf.Secret)
+	if err != nil {
+		return nil, err
+	}
+
+	foundDevices, err := iotClient.ListDevices()
+	if err != nil {
+		return nil, err
+	}
+
+	var devices []DeviceInfo
+	for _, foundDev := range foundDevices {
+		dev := DeviceInfo{
+			Name:   foundDev.Name,
+			ID:     foundDev.Id,
+			Board:  foundDev.Type,
+			Serial: foundDev.Serial,
+			FQBN:   foundDev.Fqbn,
+		}
+		devices = append(devices, dev)
+	}
+
+	return devices, nil
+}

Diff for: internal/iot/client.go

@@ -10,6 +10,7 @@ import (
 // Client can be used to perform actions on the arduino iot cloud.
 type Client interface {
 	AddDevice(fqbn, name, serial, devType string) (string, error)
+	ListDevices() ([]iotclient.ArduinoDevicev2, error)
 	AddCertificate(id, csr string) (*iotclient.ArduinoCompressedv2, error)
 }
 
@@ -47,6 +48,17 @@ func (cl *client) AddDevice(fqbn, name, serial, dType string) (string, error) {
 	return dev.Id, nil
 }
 
+// ListDevices retrieves and returns a list of all Arduino IoT Cloud devices
+// belonging to the user performing the request.
+func (cl *client) ListDevices() ([]iotclient.ArduinoDevicev2, error) {
+	devices, _, err := cl.api.DevicesV2Api.DevicesV2List(cl.ctx, nil)
+	if err != nil {
+		err = fmt.Errorf("listing devices: %w", err)
+		return nil, err
+	}
+	return devices, nil
+}
+
 // AddCertifcate allows to upload a certificate on arduino iot cloud.
 // It returns the certificate parameters populated by the cloud.
 func (cl *client) AddCertificate(id, csr string) (*iotclient.ArduinoCompressedv2, error) {