Set cmd optional params as pointers (#29)

All implemented commands now accept optional parameters as pointers.
This change makes the command package more clear and easier to use: if the type of a parameter is a pointer, then it becomes clear that such parameter is optional. So, for example, instead of an empty string now it's possible to pass nil for optional parameters.

Author: polldo

cli/device/create.go

@@ -31,9 +31,13 @@ func runCreateCommand(cmd *cobra.Command, args []string) error {
 	fmt.Printf("Creating device with name %s\n", createFlags.name)
 
 	params := &device.CreateParams{
-		Port: createFlags.port,
 		Name: createFlags.name,
-		Fqbn: createFlags.fqbn,
+	}
+	if createFlags.port != "" {
+		params.Port = &createFlags.port
+	}
+	if createFlags.fqbn != "" {
+		params.Fqbn = &createFlags.fqbn
 	}
 
 	devID, err := device.Create(params)

cli/thing/create.go

@@ -29,9 +29,11 @@ func runCreateCommand(cmd *cobra.Command, args []string) error {
 	fmt.Printf("Creating thing from template %s\n", createFlags.template)
 
 	params := &thing.CreateParams{
-		Name:     createFlags.name,
 		Template: createFlags.template,
 	}
+	if createFlags.name != "" {
+		params.Name = &createFlags.name
+	}
 
 	thingID, err := thing.Create(params)
 	if err != nil {

cli/thing/extract.go

@@ -28,7 +28,9 @@ func initExtractCommand() *cobra.Command {
 func runExtractCommand(cmd *cobra.Command, args []string) error {
 	fmt.Printf("Extracting template from thing %s\n", extractFlags.id)
 
-	params := &thing.ExtractParams{ID: extractFlags.id}
+	params := &thing.ExtractParams{
+		ID: extractFlags.id,
+	}
 	if extractFlags.outfile != "" {
 		params.Outfile = &extractFlags.outfile
 	}

command/device/create.go

@@ -13,12 +13,13 @@ import (
 
 // CreateParams contains the parameters needed
 // to find the device to be provisioned.
-// If Port is an empty string, then each serial port is analyzed.
-// If Fqbn is an empty string, then the first device found gets selected.
+// Name - mandatory parameter.
+// Port - optional parameter. If omitted then each serial port is analyzed.
+// Fqbn - optional parameter. If omitted then the first device found gets selected.
 type CreateParams struct {
-	Port string
 	Name string
-	Fqbn string
+	Port *string
+	Fqbn *string
 }
 
 type device struct {
@@ -96,31 +97,33 @@ func deviceFromPorts(ports []*rpc.DetectedPort, params *CreateParams) *device {
 	return nil
 }
 
-// portFilter filters out the given port if the port parameter is not an empty string
-// and if they do not match.
+// portFilter filters out the given port in the following cases:
+// - if the port parameter does not match the actual port address.
+// - if the the detected port does not contain any board.
 // It returns:
 // true -> to skip the port
 // false -> to keep the port
 func portFilter(port *rpc.DetectedPort, params *CreateParams) bool {
 	if len(port.Boards) == 0 {
 		return true
 	}
-	if params.Port != "" && params.Port != port.Address {
+	if params.Port != nil && *params.Port != port.Address {
 		return true
 	}
 	return false
 }
 
 // boardFilter looks for a board which has the same fqbn passed as parameter.
+// If fqbn parameter is nil, then the first board found is returned.
 // It returns:
 // - a board if it is found.
 // - nil if no board matching the fqbn parameter is found.
 func boardFilter(boards []*rpc.BoardListItem, params *CreateParams) (board *rpc.BoardListItem) {
-	if params.Fqbn == "" {
+	if params.Fqbn == nil {
 		return boards[0]
 	}
 	for _, b := range boards {
-		if b.Fqbn == params.Fqbn {
+		if b.Fqbn == *params.Fqbn {
 			return b
 		}
 	}

command/device/create_test.go

@@ -35,6 +35,10 @@ var (
 	}
 )
 
+func stringPointer(s string) *string {
+	return &s
+}
+
 func TestDeviceFromPorts(t *testing.T) {
 	tests := []struct {
 		name   string
@@ -45,50 +49,50 @@ func TestDeviceFromPorts(t *testing.T) {
 
 		{
 			name:   "port-filter",
-			filter: &CreateParams{Fqbn: "", Port: "ACM1"},
+			filter: &CreateParams{Fqbn: nil, Port: stringPointer("ACM1")},
 			ports:  portsTwoBoards,
 			want:   &device{fqbn: "arduino:avr:uno", port: "ACM1"},
 		},
 
 		{
 			name:   "fqbn-filter",
-			filter: &CreateParams{Fqbn: "arduino:avr:uno", Port: ""},
+			filter: &CreateParams{Fqbn: stringPointer("arduino:avr:uno"), Port: nil},
 			ports:  portsTwoBoards,
 			want:   &device{fqbn: "arduino:avr:uno", port: "ACM1"},
 		},
 
 		{
 			name:   "no-filter-noboards",
-			filter: &CreateParams{Fqbn: "", Port: ""},
+			filter: &CreateParams{Fqbn: nil, Port: nil},
 			ports:  portsNoBoards,
 			want:   nil,
 		},
 
 		{
 			name:   "no-filter",
-			filter: &CreateParams{Fqbn: "", Port: ""},
+			filter: &CreateParams{Fqbn: nil, Port: nil},
 			ports:  portsTwoBoards,
 			// first device found is selected
 			want: &device{fqbn: "arduino:samd:nano_33_iot", port: "ACM0"},
 		},
 
 		{
 			name:   "both-filter-noboards",
-			filter: &CreateParams{Fqbn: "arduino:avr:uno", Port: "ACM1"},
+			filter: &CreateParams{Fqbn: stringPointer("arduino:avr:uno"), Port: stringPointer("ACM1")},
 			ports:  portsNoBoards,
 			want:   nil,
 		},
 
 		{
 			name:   "both-filter-found",
-			filter: &CreateParams{Fqbn: "arduino:avr:uno", Port: "ACM1"},
+			filter: &CreateParams{Fqbn: stringPointer("arduino:avr:uno"), Port: stringPointer("ACM1")},
 			ports:  portsTwoBoards,
 			want:   &device{fqbn: "arduino:avr:uno", port: "ACM1"},
 		},
 
 		{
 			name:   "both-filter-notfound",
-			filter: &CreateParams{Fqbn: "arduino:avr:uno", Port: "ACM0"},
+			filter: &CreateParams{Fqbn: stringPointer("arduino:avr:uno"), Port: stringPointer("ACM0")},
 			ports:  portsTwoBoards,
 			want:   nil,
 		},

command/thing/create.go

@@ -15,7 +15,7 @@ import (
 // CreateParams contains the parameters needed to create a new thing.
 type CreateParams struct {
 	// Optional - contains the name of the thing
-	Name string
+	Name *string
 	// Mandatory - contains the path of the template file
 	Template string
 }
@@ -37,8 +37,8 @@ func Create(params *CreateParams) (string, error) {
 	}
 
 	// Name passed as parameter has priority over name from template
-	if params.Name != "" {
-		thing.Name = params.Name
+	if params.Name != nil {
+		thing.Name = *params.Name
 	}
 	// If name is not specified in the template, it should be passed as parameter
 	if thing.Name == "" {