feat: Unify command output format flag

cmd/common/flags.go

@@ -3,26 +3,65 @@ package common
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	flag "github.com/spf13/pflag"
 
 	consensus "github.com/oasisprotocol/oasis-core/go/consensus/api"
 )
 
 var (
-	selectedHeight int64
-	force          bool
-	answerYes      bool
+	// HeightFlag is the flag for specifying block height.
+	HeightFlag *flag.FlagSet
+
+	// ForceFlag is a force mode switch.
+	ForceFlag *flag.FlagSet
+
+	// AnswerYesFlag answers yes to all questions.
+	AnswerYesFlag *flag.FlagSet
+
+	// FormatFlag specifies the command's output format (text/json).
+	FormatFlag *flag.FlagSet
 )
 
-// HeightFlag is the flag for specifying block height.
-var HeightFlag *flag.FlagSet
+// FormatType specifies the type of format for output of commands.
+type FormatType string
 
-// ForceFlag is a force mode switch.
-var ForceFlag *flag.FlagSet
+// Supported output formats for the format flag.
+const (
+	// Output plain text.
+	FormatText FormatType = "text"
+	// Output JSON.
+	FormatJSON FormatType = "json"
+)
+
+// String returns a string representation of the output format type.
+func (f *FormatType) String() string {
+	return string(*f)
+}
 
-// AnswerYesFlag answers yes to all questions.
-var AnswerYesFlag *flag.FlagSet
+// Set sets the value of the type to the argument given.
+func (f *FormatType) Set(v string) error {
+	switch strings.ToLower(v) {
+	case string(FormatText), string(FormatJSON):
+		*f = FormatType(v)
+		return nil
+	default:
+		return fmt.Errorf("unknown output format type, must be one of: %s", strings.Join([]string{string(FormatText), string(FormatJSON)}, ", "))
+	}
+}
+
+// Type returns the type of the flag.
+func (f *FormatType) Type() string {
+	return "FormatType"
+}
+
+var (
+	selectedHeight int64
+	force          bool
+	answerYes      bool
+	outputFormat   = FormatText
+)
 
 // GetHeight returns the user-selected block height.
 func GetHeight() int64 {
@@ -34,11 +73,17 @@ func IsForce() bool {
 	return force
 }
 
-// IsForce returns force mode.
+// GetAnswerYes returns whether all interactive questions should be answered
+// with yes.
 func GetAnswerYes() bool {
 	return answerYes
 }
 
+// OutputFormat returns the format of the command's output.
+func OutputFormat() FormatType {
+	return outputFormat
+}
+
 // GetActualHeight returns the user-selected block height if explicitly
 // specified, or the current latest height.
 func GetActualHeight(
@@ -65,4 +110,7 @@ func init() {
 
 	AnswerYesFlag = flag.NewFlagSet("", flag.ContinueOnError)
 	AnswerYesFlag.BoolVarP(&answerYes, "yes", "y", false, "answer yes to all questions")
+
+	FormatFlag = flag.NewFlagSet("", flag.ContinueOnError)
+	FormatFlag.Var(&outputFormat, "format", "output format ["+strings.Join([]string{string(FormatText), string(FormatJSON)}, ",")+"]")
 }

cmd/network/show.go

@@ -9,7 +9,6 @@ import (
 	"strings"
 
 	"github.com/spf13/cobra"
-	flag "github.com/spf13/pflag"
 
 	"github.com/oasisprotocol/oasis-core/go/common/crypto/signature"
 	consensusPretty "github.com/oasisprotocol/oasis-core/go/common/prettyprint"
@@ -428,7 +427,7 @@ func showParameters(ctx context.Context, npa *common.NPASelection, height int64,
 	doc := make(map[string]interface{})
 
 	doSection := func(name string, params interface{}) {
-		if outputFormat == formatJSON {
+		if common.OutputFormat() == common.FormatJSON {
 			doc[name] = params
 		} else {
 			fmt.Printf("=== %s PARAMETERS ===\n", strings.ToUpper(name))
@@ -446,18 +445,15 @@ func showParameters(ctx context.Context, npa *common.NPASelection, height int64,
 	doSection("beacon", beaconParams)
 	doSection("governance", governanceParams)
 
-	if outputFormat == formatJSON {
+	if common.OutputFormat() == common.FormatJSON {
 		pp, err := json.MarshalIndent(doc, "", "  ")
 		cobra.CheckErr(err)
 		fmt.Printf("%s\n", pp)
 	}
 }
 
 func init() {
-	formatFlag := flag.NewFlagSet("", flag.ContinueOnError)
-	formatFlag.StringVar(&outputFormat, "format", formatText, "output format ["+strings.Join([]string{formatText, formatJSON}, ",")+"]")
-	showCmd.Flags().AddFlagSet(formatFlag)
-
 	showCmd.Flags().AddFlagSet(common.SelectorNFlags)
 	showCmd.Flags().AddFlagSet(common.HeightFlag)
+	showCmd.Flags().AddFlagSet(common.FormatFlag)
 }