Extract templates to stdout (#89)

Use stdout as primary output outlet of extract commands to allow piping the results for whatever reason

Author: Paolo Calao

README.md

@@ -154,9 +154,9 @@ Delete a thing with the following command:
 
 `$ arduino-cloud-cli thing delete --id <thingID>`
 
-Extract a template from an existing thing. The template can be saved in two formats: json or yaml. The default format is yaml:
+Extract a template from an existing thing. The template is printed to stdout and its format depends on the global `--format` flag:
 
-`$ arduino-cloud-cli thing extract --id <thingID> --outfile <templateFile> --format <yaml|json>`
+`$ arduino-cloud-cli thing extract --id <thingID> --format <json|yaml>`
 
 Bind a thing to an existing device:
 
@@ -198,9 +198,9 @@ Delete a dashboard with the following command:
 
 `$ arduino-cloud-cli dashboard delete --id <dashboardID>`
 
-Extract a template from an existing dashboard. The template can be saved in two formats: json or yaml. The default format is yaml:
+Extract a template from an existing dashboard. The template is printed to stdout and its format depends on the global `--format` flag:
 
-`$ arduino-cloud-cli dashboard extract --id <dashboardID> --outfile <templateFile> --format <yaml|json>`
+`$ arduino-cloud-cli dashboard extract --id <dashboardID> --format <json|yaml>`
 
 Create a dashboard: dashboards can be created only starting from a template. Supported dashboard template formats are JSON and YAML. The name parameter is optional. If it is provided then it overrides the name retrieved from the template. The `override` flag can be used to override the template `thing_id` placeholder with the actual ID of the thing to be used.
 

cli/dashboard/extract.go

@@ -25,29 +25,21 @@ import (
 	"github.com/arduino/arduino-cloud-cli/command/dashboard"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
 )
 
 var extractFlags struct {
-	id      string
-	outfile string
-	format  string
+	id string
 }
 
 func initExtractCommand() *cobra.Command {
 	extractCommand := &cobra.Command{
 		Use:   "extract",
 		Short: "Extract a template from a dashboard",
-		Long:  "Extract a template from a Arduino IoT Cloud dashboard and save it in a file",
+		Long:  "Extract a template from a Arduino IoT Cloud dashboard",
 		Run:   runExtractCommand,
 	}
 	extractCommand.Flags().StringVarP(&extractFlags.id, "id", "i", "", "Dashboard ID")
-	extractCommand.Flags().StringVarP(&extractFlags.outfile, "outfile", "o", "", "Template file destination path")
-	extractCommand.Flags().StringVar(
-		&extractFlags.format,
-		"format",
-		"yaml",
-		"Format of template file, can be {json|yaml}. Default is 'yaml'",
-	)
 
 	extractCommand.MarkFlagRequired("id")
 	return extractCommand
@@ -57,18 +49,31 @@ func runExtractCommand(cmd *cobra.Command, args []string) {
 	logrus.Infof("Extracting template from dashboard %s", extractFlags.id)
 
 	params := &dashboard.ExtractParams{
-		ID:     extractFlags.id,
-		Format: extractFlags.format,
-	}
-	if extractFlags.outfile != "" {
-		params.Outfile = &extractFlags.outfile
+		ID: extractFlags.id,
 	}
 
-	err := dashboard.Extract(params)
+	template, err := dashboard.Extract(params)
 	if err != nil {
 		feedback.Errorf("Error during template extraction: %v", err)
 		os.Exit(errorcodes.ErrGeneric)
 	}
 
-	logrus.Info("Template successfully extracted")
+	feedback.PrintResult(extractResult{template})
+}
+
+type extractResult struct {
+	template map[string]interface{}
+}
+
+func (r extractResult) Data() interface{} {
+	return r.template
+}
+
+func (r extractResult) String() string {
+	t, err := yaml.Marshal(r.template)
+	if err != nil {
+		feedback.Errorf("Error during template parsing: %v", err)
+		os.Exit(errorcodes.ErrGeneric)
+	}
+	return string(t)
 }

cli/thing/extract.go

@@ -25,29 +25,21 @@ import (
 	"github.com/arduino/arduino-cloud-cli/command/thing"
 	"github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
 )
 
 var extractFlags struct {
-	id      string
-	outfile string
-	format  string
+	id string
 }
 
 func initExtractCommand() *cobra.Command {
 	extractCommand := &cobra.Command{
 		Use:   "extract",
 		Short: "Extract a template from a thing",
-		Long:  "Extract a template from a Arduino IoT Cloud thing and save it in a file",
+		Long:  "Extract a template from a Arduino IoT Cloud thing",
 		Run:   runExtractCommand,
 	}
 	extractCommand.Flags().StringVarP(&extractFlags.id, "id", "i", "", "Thing ID")
-	extractCommand.Flags().StringVarP(&extractFlags.outfile, "outfile", "o", "", "Template file destination path")
-	extractCommand.Flags().StringVar(
-		&extractFlags.format,
-		"format",
-		"yaml",
-		"Format of template file, can be {json|yaml}. Default is 'yaml'",
-	)
 
 	extractCommand.MarkFlagRequired("id")
 	return extractCommand
@@ -57,18 +49,31 @@ func runExtractCommand(cmd *cobra.Command, args []string) {
 	logrus.Infof("Extracting template from thing %s", extractFlags.id)
 
 	params := &thing.ExtractParams{
-		ID:     extractFlags.id,
-		Format: extractFlags.format,
-	}
-	if extractFlags.outfile != "" {
-		params.Outfile = &extractFlags.outfile
+		ID: extractFlags.id,
 	}
 
-	err := thing.Extract(params)
+	template, err := thing.Extract(params)
 	if err != nil {
 		feedback.Errorf("Error during template extraction: %v", err)
 		os.Exit(errorcodes.ErrGeneric)
 	}
 
-	logrus.Info("Template successfully extracted")
+	feedback.PrintResult(extractResult{template})
+}
+
+type extractResult struct {
+	template map[string]interface{}
+}
+
+func (r extractResult) Data() interface{} {
+	return r.template
+}
+
+func (r extractResult) String() string {
+	t, err := yaml.Marshal(r.template)
+	if err != nil {
+		feedback.Errorf("Error during template parsing: %v", err)
+		os.Exit(errorcodes.ErrGeneric)
+	}
+	return string(t)
 }

command/dashboard/extract.go

@@ -18,64 +18,36 @@
 package dashboard
 
 import (
-	"errors"
 	"fmt"
-	"strings"
 
 	"github.com/arduino/arduino-cloud-cli/internal/config"
 	"github.com/arduino/arduino-cloud-cli/internal/iot"
 	"github.com/arduino/arduino-cloud-cli/internal/template"
-	"github.com/sirupsen/logrus"
 )
 
 // ExtractParams contains the parameters needed to
-// extract a template dashboard from Arduino IoT Cloud and save it on local storage.
+// extract a template dashboard from Arduino IoT Cloud.
 type ExtractParams struct {
-	ID      string
-	Format  string  // Format determines the file format of the template ("json" or "yaml")
-	Outfile *string // Destination path of the extracted template
+	ID string
 }
 
 // Extract command is used to extract a dashboard template
 // from a dashboard on Arduino IoT Cloud.
-func Extract(params *ExtractParams) error {
-	params.Format = strings.ToLower(params.Format)
-	if params.Format != "json" && params.Format != "yaml" {
-		return errors.New("format is not valid: only 'json' and 'yaml' are supported")
-	}
-
+func Extract(params *ExtractParams) (map[string]interface{}, error) {
 	conf, err := config.Retrieve()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	iotClient, err := iot.NewClient(conf.Client, conf.Secret)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	dashboard, err := iotClient.DashboardShow(params.ID)
 	if err != nil {
 		err = fmt.Errorf("%s: %w", "cannot extract dashboard: ", err)
-		return err
-	}
-
-	templ := template.FromDashboard(dashboard)
-
-	if params.Outfile == nil {
-		name, ok := templ["name"].(string)
-		if name == "" || !ok {
-			return errors.New("dashboard template does not have a valid name")
-		}
-		name = strings.Join(strings.Fields(name), "")
-		outfile := name + "-dashboard." + params.Format
-		params.Outfile = &outfile
-	}
-
-	logrus.Infof("Extracting template in file: %s", *params.Outfile)
-	err = template.ToFile(templ, *params.Outfile, params.Format)
-	if err != nil {
-		return fmt.Errorf("saving template: %w", err)
+		return nil, err
 	}
 
-	return nil
+	return template.FromDashboard(dashboard), nil
 }

command/thing/extract.go

@@ -18,64 +18,36 @@
 package thing
 
 import (
-	"errors"
 	"fmt"
-	"strings"
 
 	"github.com/arduino/arduino-cloud-cli/internal/config"
 	"github.com/arduino/arduino-cloud-cli/internal/iot"
 	"github.com/arduino/arduino-cloud-cli/internal/template"
-	"github.com/sirupsen/logrus"
 )
 
 // ExtractParams contains the parameters needed to
-// extract a template thing from Arduino IoT Cloud and save it on local storage.
+// extract a template thing from Arduino IoT Cloud.
 type ExtractParams struct {
-	ID      string
-	Format  string  // Format determines the file format of the template ("json" or "yaml")
-	Outfile *string // Destination path of the extracted template
+	ID string
 }
 
 // Extract command is used to extract a thing template
 // from a thing on Arduino IoT Cloud.
-func Extract(params *ExtractParams) error {
-	params.Format = strings.ToLower(params.Format)
-	if params.Format != "json" && params.Format != "yaml" {
-		return errors.New("format is not valid: only 'json' and 'yaml' are supported")
-	}
-
+func Extract(params *ExtractParams) (map[string]interface{}, error) {
 	conf, err := config.Retrieve()
 	if err != nil {
-		return err
+		return nil, err
 	}
 	iotClient, err := iot.NewClient(conf.Client, conf.Secret)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	thing, err := iotClient.ThingShow(params.ID)
 	if err != nil {
 		err = fmt.Errorf("%s: %w", "cannot extract thing: ", err)
-		return err
-	}
-
-	templ := template.FromThing(thing)
-
-	if params.Outfile == nil {
-		name, ok := templ["name"].(string)
-		if name == "" || !ok {
-			return errors.New("thing template does not have a valid name")
-		}
-		name = strings.Join(strings.Fields(name), "")
-		outfile := name + "-thing." + params.Format
-		params.Outfile = &outfile
-	}
-
-	logrus.Infof("Extracting template in file: %s", *params.Outfile)
-	err = template.ToFile(templ, *params.Outfile, params.Format)
-	if err != nil {
-		return fmt.Errorf("saving template: %w", err)
+		return nil, err
 	}
 
-	return nil
+	return template.FromThing(thing), nil
 }