Add JSON and YAML output to svcat (#1944)

* Initial WIP commit for adding JSON/YAML output to svcat

This adds JSON/YAML output to svcat, but does not currently include
the Type Metadata, so we lose the Kind/GroupVersion info.

* Adding JSON and YAML output capabilities

Note: This is not 100% complete. Right now, we do not obtain the
metav1.TypeMeta within svcat. We will need to figure out how to
populate this.

See: kubernetes/client-go#308 (comment)

Fixes: #1814

* Code review comments

* Code review comments

* Added boilerplate on json.go

Author: jeremyrickard

cmd/svcat/binding/get_cmd.go

@@ -24,7 +24,12 @@ import (
 
 type getCmd struct {
 	*command.Namespaced
-	name string
+	name         string
+	outputFormat string
+}
+
+func (c *getCmd) SetFormat(format string) {
+	c.outputFormat = format
 }
 
 // NewGetCmd builds a "svcat get bindings" command
@@ -45,7 +50,7 @@ func NewGetCmd(cxt *command.Context) *cobra.Command {
 	}
 
 	command.AddNamespaceFlags(cmd.Flags(), true)
-
+	command.AddOutputFlags(cmd.Flags())
 	return cmd
 }
 
@@ -71,7 +76,7 @@ func (c *getCmd) getAll() error {
 		return err
 	}
 
-	output.WriteBindingList(c.Output, bindings.Items...)
+	output.WriteBindingList(c.Output, c.outputFormat, bindings)
 	return nil
 }
 
@@ -81,6 +86,6 @@ func (c *getCmd) get() error {
 		return err
 	}
 
-	output.WriteBindingList(c.Output, *binding)
+	output.WriteBinding(c.Output, c.outputFormat, *binding)
 	return nil
 }

cmd/svcat/broker/get_cmd.go

@@ -24,7 +24,12 @@ import (
 
 type getCmd struct {
 	*command.Context
-	name string
+	name         string
+	outputFormat string
+}
+
+func (c *getCmd) SetFormat(format string) {
+	c.outputFormat = format
 }
 
 // NewGetCmd builds a "svcat get brokers" command
@@ -41,7 +46,7 @@ func NewGetCmd(cxt *command.Context) *cobra.Command {
 		PreRunE: command.PreRunE(getCmd),
 		RunE:    command.RunE(getCmd),
 	}
-
+	command.AddOutputFlags(cmd.Flags())
 	return cmd
 }
 
@@ -67,7 +72,7 @@ func (c *getCmd) getAll() error {
 		return err
 	}
 
-	output.WriteBrokerList(c.Output, brokers...)
+	output.WriteBrokerList(c.Output, c.outputFormat, brokers...)
 	return nil
 }
 
@@ -77,6 +82,6 @@ func (c *getCmd) get() error {
 		return err
 	}
 
-	output.WriteBrokerList(c.Output, *broker)
+	output.WriteBroker(c.Output, c.outputFormat, *broker)
 	return nil
 }

cmd/svcat/class/get_cmd.go

@@ -28,6 +28,11 @@ type getCmd struct {
 	lookupByUUID bool
 	uuid         string
 	name         string
+	outputFormat string
+}
+
+func (c *getCmd) SetFormat(format string) {
+	c.outputFormat = format
 }
 
 // NewGetCmd builds a "svcat get classes" command
@@ -52,6 +57,7 @@ func NewGetCmd(cxt *command.Context) *cobra.Command {
 		false,
 		"Whether or not to get the class by UUID (the default is by name)",
 	)
+	command.AddOutputFlags(cmd.Flags())
 	return cmd
 }
 
@@ -81,7 +87,7 @@ func (c *getCmd) getAll() error {
 		return err
 	}
 
-	output.WriteClassList(c.Output, classes...)
+	output.WriteClassList(c.Output, c.outputFormat, classes...)
 	return nil
 }
 
@@ -98,6 +104,6 @@ func (c *getCmd) get() error {
 		return err
 	}
 
-	output.WriteClassList(c.Output, *class)
+	output.WriteClass(c.Output, c.outputFormat, *class)
 	return nil
 }

cmd/svcat/command/command.go

@@ -17,8 +17,10 @@ limitations under the License.
 package command
 
 import (
+	"fmt"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
+	"strings"
 )
 
 // Command represents an svcat command.
@@ -41,13 +43,27 @@ type NamespacedCommand interface {
 	SetNamespace(namespace string)
 }
 
+// FormattedCommand represents a command that can have it's output
+// formatted
+type FormattedCommand interface {
+	// SetFormat sets the commands output format
+	SetFormat(format string)
+}
+
 // PreRunE validates os args, and then saves them on the svcat command.
 func PreRunE(cmd Command) func(*cobra.Command, []string) error {
 	return func(c *cobra.Command, args []string) error {
 		if nsCmd, ok := cmd.(NamespacedCommand); ok {
 			namespace := DetermineNamespace(c.Flags(), nsCmd.GetContext().App.CurrentNamespace)
 			nsCmd.SetNamespace(namespace)
 		}
+		if fmtCmd, ok := cmd.(FormattedCommand); ok {
+			fmtString, err := determineOutputFormat(c.Flags())
+			if err != nil {
+				return err
+			}
+			fmtCmd.SetFormat(fmtString)
+		}
 		return cmd.Validate(args)
 	}
 }
@@ -93,3 +109,29 @@ func DetermineNamespace(flags *pflag.FlagSet, currentNamespace string) string {
 
 	return currentNamespace
 }
+
+// AddOutputFlags adds common output flags to a command that can have variable output formats.
+func AddOutputFlags(flags *pflag.FlagSet) {
+	flags.StringP(
+		"output",
+		"o",
+		"",
+		"The output format to use. Valid options are table, json or yaml. If not present, defaults to table",
+	)
+}
+
+func determineOutputFormat(flags *pflag.FlagSet) (string, error) {
+	format, _ := flags.GetString("output")
+	format = strings.ToLower(format)
+
+	switch format {
+	case "", "table":
+		return "table", nil
+	case "json":
+		return "json", nil
+	case "yaml":
+		return "yaml", nil
+	default:
+		return "", fmt.Errorf("invalid --output format %q, allowed values are table, json and yaml", format)
+	}
+}

cmd/svcat/instance/get_cmd.go

@@ -24,7 +24,12 @@ import (
 
 type getCmd struct {
 	*command.Namespaced
-	name string
+	name         string
+	outputFormat string
+}
+
+func (c *getCmd) SetFormat(format string) {
+	c.outputFormat = format
 }
 
 // NewGetCmd builds a "svcat get instances" command
@@ -44,6 +49,7 @@ func NewGetCmd(cxt *command.Context) *cobra.Command {
 		RunE:    command.RunE(getCmd),
 	}
 	command.AddNamespaceFlags(cmd.Flags(), true)
+	command.AddOutputFlags(cmd.Flags())
 	return cmd
 }
 
@@ -69,7 +75,7 @@ func (c *getCmd) getAll() error {
 		return err
 	}
 
-	output.WriteInstanceList(c.Output, instances.Items...)
+	output.WriteInstanceList(c.Output, c.outputFormat, instances)
 	return nil
 }
 
@@ -79,6 +85,7 @@ func (c *getCmd) get() error {
 		return err
 	}
 
-	output.WriteInstanceList(c.Output, *instance)
+	output.WriteInstance(c.Output, c.outputFormat, *instance)
+
 	return nil
 }

cmd/svcat/output/binding.go

@@ -40,8 +40,7 @@ func getBindingStatusFull(status v1beta1.ServiceBindingStatus) string {
 	return formatStatusFull(string(lastCond.Type), lastCond.Status, lastCond.Reason, lastCond.Message, lastCond.LastTransitionTime)
 }
 
-// WriteBindingList prints a list of bindings.
-func WriteBindingList(w io.Writer, bindings ...v1beta1.ServiceBinding) {
+func writeBindingListTable(w io.Writer, bindingList *v1beta1.ServiceBindingList) {
 	t := NewListTable(w)
 	t.SetHeader([]string{
 		"Name",
@@ -50,18 +49,44 @@ func WriteBindingList(w io.Writer, bindings ...v1beta1.ServiceBinding) {
 		"Status",
 	})
 
-	for _, binding := range bindings {
+	for _, binding := range bindingList.Items {
 		t.Append([]string{
 			binding.Name,
 			binding.Namespace,
 			binding.Spec.ServiceInstanceRef.Name,
 			getBindingStatusShort(binding.Status),
 		})
 	}
-
 	t.Render()
 }
 
+// WriteBindingList prints a list of bindings in the specified output format.
+func WriteBindingList(w io.Writer, outputFormat string, bindingList *v1beta1.ServiceBindingList) {
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, bindingList)
+	case formatYAML:
+		writeYAML(w, bindingList, 0)
+	case formatTable:
+		writeBindingListTable(w, bindingList)
+	}
+}
+
+// WriteBinding prints a single bindings in the specified output format.
+func WriteBinding(w io.Writer, outputFormat string, binding v1beta1.ServiceBinding) {
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, binding)
+	case formatYAML:
+		writeYAML(w, binding, 0)
+	case formatTable:
+		l := v1beta1.ServiceBindingList{
+			Items: []v1beta1.ServiceBinding{binding},
+		}
+		writeBindingListTable(w, &l)
+	}
+}
+
 // WriteBindingDetails prints details for a single binding.
 func WriteBindingDetails(w io.Writer, binding *v1beta1.ServiceBinding) {
 	t := NewDetailsTable(w)

cmd/svcat/output/broker.go

@@ -40,8 +40,7 @@ func getBrokerStatusFull(status v1beta1.ClusterServiceBrokerStatus) string {
 	return formatStatusFull(string(lastCond.Type), lastCond.Status, lastCond.Reason, lastCond.Message, lastCond.LastTransitionTime)
 }
 
-// WriteBrokerList prints a list of brokers.
-func WriteBrokerList(w io.Writer, brokers ...v1beta1.ClusterServiceBroker) {
+func writeBrokerListTable(w io.Writer, brokers []v1beta1.ClusterServiceBroker) {
 	t := NewListTable(w)
 	t.SetHeader([]string{
 		"Name",
@@ -58,6 +57,33 @@ func WriteBrokerList(w io.Writer, brokers ...v1beta1.ClusterServiceBroker) {
 	t.Render()
 }
 
+// WriteBrokerList prints a list of brokers in the specified output format.
+func WriteBrokerList(w io.Writer, outputFormat string, brokers ...v1beta1.ClusterServiceBroker) {
+	l := v1beta1.ClusterServiceBrokerList{
+		Items: brokers,
+	}
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, l)
+	case formatYAML:
+		writeYAML(w, l, 0)
+	case formatTable:
+		writeBrokerListTable(w, brokers)
+	}
+}
+
+// WriteBroker prints a broker in the specified output format.
+func WriteBroker(w io.Writer, outputFormat string, broker v1beta1.ClusterServiceBroker) {
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, broker)
+	case formatYAML:
+		writeYAML(w, broker, 0)
+	case formatTable:
+		writeBrokerListTable(w, []v1beta1.ClusterServiceBroker{broker})
+	}
+}
+
 // WriteParentBroker prints identifying information for a parent broker.
 func WriteParentBroker(w io.Writer, broker *v1beta1.ClusterServiceBroker) {
 	fmt.Fprintln(w, "\nBroker:")

cmd/svcat/output/class.go

@@ -17,10 +17,12 @@ limitations under the License.
 package output
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"strings"
 
+	"github.com/ghodss/yaml"
 	"github.com/kubernetes-incubator/service-catalog/pkg/apis/servicecatalog/v1beta1"
 )
 
@@ -31,8 +33,7 @@ func getClassStatusText(status v1beta1.ClusterServiceClassStatus) string {
 	return statusActive
 }
 
-// WriteClassList prints a list of classes.
-func WriteClassList(w io.Writer, classes ...v1beta1.ClusterServiceClass) {
+func writeClassListTable(w io.Writer, classes []v1beta1.ClusterServiceClass) {
 	t := NewListTable(w)
 	t.SetHeader([]string{
 		"Name",
@@ -49,6 +50,49 @@ func WriteClassList(w io.Writer, classes ...v1beta1.ClusterServiceClass) {
 	t.Render()
 }
 
+func writeClassListJSON(w io.Writer, classes []v1beta1.ClusterServiceClass) {
+	classList := v1beta1.ClusterServiceClassList{
+		Items: classes,
+	}
+	j, _ := json.MarshalIndent(classList, "", "   ")
+	w.Write(j)
+}
+
+func writeClassListYAML(w io.Writer, classes []v1beta1.ClusterServiceClass) {
+	classList := v1beta1.ClusterServiceClassList{
+		Items: classes,
+	}
+	y, _ := yaml.Marshal(classList)
+	w.Write(y)
+}
+
+// WriteClassList prints a list of classes in the specified output format.
+func WriteClassList(w io.Writer, outputFormat string, classes ...v1beta1.ClusterServiceClass) {
+	classList := v1beta1.ClusterServiceClassList{
+		Items: classes,
+	}
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, classList)
+	case formatYAML:
+		writeYAML(w, classList, 0)
+	case formatTable:
+		writeClassListTable(w, classes)
+	}
+}
+
+// WriteClass prints a single class in the specified output format.
+func WriteClass(w io.Writer, outputFormat string, class v1beta1.ClusterServiceClass) {
+	switch outputFormat {
+	case formatJSON:
+		writeJSON(w, class)
+	case formatYAML:
+		writeYAML(w, class, 0)
+	case formatTable:
+		writeClassListTable(w, []v1beta1.ClusterServiceClass{class})
+	}
+}
+
 // WriteParentClass prints identifying information for a parent class.
 func WriteParentClass(w io.Writer, class *v1beta1.ClusterServiceClass) {
 	fmt.Fprintln(w, "\nClass:")