Merge pull request #1 from ivey/required_flags

Required flags

app.go

@@ -87,14 +87,25 @@ func (a *App) Run(arguments []string) error {
 	set.SetOutput(ioutil.Discard)
 	err := set.Parse(arguments[1:])
 	nerr := normalizeFlags(a.Flags, set)
+	cerr := checkRequiredFlags(a.Flags, set)
+
+	context := NewContext(a, set, set)
+
 	if nerr != nil {
 		fmt.Println(nerr)
-		context := NewContext(a, set, set)
+		fmt.Println("")
 		ShowAppHelp(context)
 		fmt.Println("")
 		return nerr
 	}
-	context := NewContext(a, set, set)
+
+	if cerr != nil {
+		fmt.Println(cerr)
+		fmt.Println("")
+		ShowAppHelp(context)
+		fmt.Println("")
+		return cerr
+	}
 
 	if err != nil {
 		fmt.Printf("Incorrect Usage.\n\n")
@@ -164,10 +175,13 @@ func (a *App) RunAsSubcommand(ctx *Context) error {
 	set.SetOutput(ioutil.Discard)
 	err := set.Parse(ctx.Args().Tail())
 	nerr := normalizeFlags(a.Flags, set)
+	cerr := checkRequiredFlags(a.Flags, set)
+
 	context := NewContext(a, set, ctx.globalSet)
 
 	if nerr != nil {
 		fmt.Println(nerr)
+		fmt.Println("")
 		if len(a.Commands) > 0 {
 			ShowSubcommandHelp(context)
 		} else {
@@ -177,6 +191,20 @@ func (a *App) RunAsSubcommand(ctx *Context) error {
 		return nerr
 	}
 
+	if cerr != nil {
+		fmt.Println(cerr)
+		fmt.Println("")
+		if len(a.Commands) > 0 {
+			ShowSubcommandHelp(context)
+			fmt.Println("subcommands")
+		} else {
+			ShowCommandHelp(ctx, context.Args().First())
+			fmt.Println("commands")
+		}
+		fmt.Println("")
+		return cerr
+	}
+
 	if err != nil {
 		fmt.Printf("Incorrect Usage.\n\n")
 		ShowSubcommandHelp(context)

command.go

@@ -88,6 +88,16 @@ func (c Command) Run(ctx *Context) error {
 		fmt.Println("")
 		return nerr
 	}
+
+	cerr := checkRequiredFlags(c.Flags, set)
+	if cerr != nil {
+		fmt.Println(cerr)
+		fmt.Println("")
+		ShowCommandHelp(ctx, c.Name)
+		fmt.Println("")
+		return cerr
+	}
+
 	context := NewContext(ctx.App, set, ctx.globalSet)
 
 	if checkCommandCompletions(context, c.Name) {

context.go

@@ -3,6 +3,7 @@ package cli
 import (
 	"errors"
 	"flag"
+	"fmt"
 	"strconv"
 	"strings"
 	"time"
@@ -337,3 +338,20 @@ func normalizeFlags(flags []Flag, set *flag.FlagSet) error {
 	}
 	return nil
 }
+
+func checkRequiredFlags(flags []Flag, set *flag.FlagSet) error {
+	visited := make(map[string]bool)
+	set.Visit(func(f *flag.Flag) {
+		visited[f.Name] = true
+	})
+
+	for _, f := range flags {
+		if f.IsRequired() {
+			key := strings.Split(f.getName(), ",")[0]
+			if !visited[key] {
+				return fmt.Errorf("Required flag %s not set", f.getName())
+			}
+		}
+	}
+	return nil
+}

flag.go

@@ -34,6 +34,7 @@ type Flag interface {
 	// Apply Flag settings to the given flag set
 	Apply(*flag.FlagSet)
 	getName() string
+	IsRequired() bool
 }
 
 func flagSet(name string, flags []Flag) *flag.FlagSet {
@@ -61,14 +62,15 @@ type Generic interface {
 
 // GenericFlag is the flag type for types implementing Generic
 type GenericFlag struct {
-	Name   string
+	Name     string
-	Value  Generic
+	Value    Generic
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f GenericFlag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s%s %v\t`%v` %s", prefixFor(f.Name), f.Name, f.Value, "-"+f.Name+" option -"+f.Name+" option", f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s%s %v\t`%v` %s", prefixFor(f.Name), f.Name, f.Value, "-"+f.Name+" option -"+f.Name+" option", f.Usage))
 }
 
 func (f GenericFlag) Apply(set *flag.FlagSet) {
@@ -88,6 +90,10 @@ func (f GenericFlag) getName() string {
 	return f.Name
 }
 
+func (f GenericFlag) IsRequired() bool {
+	return f.Required
+}
+
 type StringSlice []string
 
 func (f *StringSlice) Set(value string) error {
@@ -104,16 +110,17 @@ func (f *StringSlice) Value() []string {
 }
 
 type StringSliceFlag struct {
-	Name   string
+	Name     string
-	Value  *StringSlice
+	Value    *StringSlice
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f StringSliceFlag) String() string {
 	firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
 	pref := prefixFor(firstName)
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
 }
 
 func (f StringSliceFlag) Apply(set *flag.FlagSet) {
@@ -136,6 +143,10 @@ func (f StringSliceFlag) getName() string {
 	return f.Name
 }
 
+func (f StringSliceFlag) IsRequired() bool {
+	return f.Required
+}
+
 type IntSlice []int
 
 func (f *IntSlice) Set(value string) error {
@@ -158,16 +169,17 @@ func (f *IntSlice) Value() []int {
 }
 
 type IntSliceFlag struct {
-	Name   string
+	Name     string
-	Value  *IntSlice
+	Value    *IntSlice
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f IntSliceFlag) String() string {
 	firstName := strings.Trim(strings.Split(f.Name, ",")[0], " ")
 	pref := prefixFor(firstName)
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), pref+firstName+" option "+pref+firstName+" option", f.Usage))
 }
 
 func (f IntSliceFlag) Apply(set *flag.FlagSet) {
@@ -193,14 +205,19 @@ func (f IntSliceFlag) getName() string {
 	return f.Name
 }
 
+func (f IntSliceFlag) IsRequired() bool {
+	return f.Required
+}
+
 type BoolFlag struct {
-	Name   string
+	Name     string
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f BoolFlag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
 }
 
 func (f BoolFlag) Apply(set *flag.FlagSet) {
@@ -223,14 +240,19 @@ func (f BoolFlag) getName() string {
 	return f.Name
 }
 
+func (f BoolFlag) IsRequired() bool {
+	return f.Required
+}
+
 type BoolTFlag struct {
-	Name   string
+	Name     string
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f BoolTFlag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s\t%v", prefixedNames(f.Name), f.Usage))
 }
 
 func (f BoolTFlag) Apply(set *flag.FlagSet) {
@@ -253,11 +275,16 @@ func (f BoolTFlag) getName() string {
 	return f.Name
 }
 
+func (f BoolTFlag) IsRequired() bool {
+	return f.Required
+}
+
 type StringFlag struct {
-	Name   string
+	Name     string
-	Value  string
+	Value    string
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f StringFlag) String() string {
@@ -270,7 +297,7 @@ func (f StringFlag) String() string {
 		fmtString = "%s %v\t%v"
 	}
 
-	return withEnvHint(f.EnvVar, fmt.Sprintf(fmtString, prefixedNames(f.Name), f.Value, f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf(fmtString, prefixedNames(f.Name), f.Value, f.Usage))
 }
 
 func (f StringFlag) Apply(set *flag.FlagSet) {
@@ -289,15 +316,20 @@ func (f StringFlag) getName() string {
 	return f.Name
 }
 
+func (f StringFlag) IsRequired() bool {
+	return f.Required
+}
+
 type IntFlag struct {
-	Name   string
+	Name     string
-	Value  int
+	Value    int
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f IntFlag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
 }
 
 func (f IntFlag) Apply(set *flag.FlagSet) {
@@ -319,15 +351,20 @@ func (f IntFlag) getName() string {
 	return f.Name
 }
 
+func (f IntFlag) IsRequired() bool {
+	return f.Required
+}
+
 type DurationFlag struct {
-	Name   string
+	Name     string
-	Value  time.Duration
+	Value    time.Duration
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f DurationFlag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
 }
 
 func (f DurationFlag) Apply(set *flag.FlagSet) {
@@ -349,15 +386,20 @@ func (f DurationFlag) getName() string {
 	return f.Name
 }
 
+func (f DurationFlag) IsRequired() bool {
+	return f.Required
+}
+
 type Float64Flag struct {
-	Name   string
+	Name     string
-	Value  float64
+	Value    float64
-	Usage  string
+	Usage    string
-	EnvVar string
+	EnvVar   string
+	Required bool
 }
 
 func (f Float64Flag) String() string {
-	return withEnvHint(f.EnvVar, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
+	return withHints(f.EnvVar, f.Required, fmt.Sprintf("%s '%v'\t%v", prefixedNames(f.Name), f.Value, f.Usage))
 }
 
 func (f Float64Flag) Apply(set *flag.FlagSet) {
@@ -379,6 +421,10 @@ func (f Float64Flag) getName() string {
 	return f.Name
 }
 
+func (f Float64Flag) IsRequired() bool {
+	return f.Required
+}
+
 func prefixFor(name string) (prefix string) {
 	if len(name) == 1 {
 		prefix = "-"
@@ -408,3 +454,15 @@ func withEnvHint(envVar, str string) string {
 	}
 	return str + envText
 }
+
+func withRequiredHint(isRequired bool, str string) string {
+	if isRequired {
+		return str + " (required)"
+	}
+
+	return str
+}
+
+func withHints(envVar string, isRequired bool, str string) string {
+	return withRequiredHint(isRequired, withEnvHint(envVar, str))
+}

required_flags_test.go

@@ -0,0 +1,60 @@
+package cli
+
+import (
+	"flag"
+	"testing"
+)
+
+func TestContext_CheckRequiredFlagsSuccess(t *testing.T) {
+	flags := []Flag{
+		StringFlag{
+			Name:     "required",
+			Required: true,
+		},
+		StringFlag{
+			Name: "optional",
+		},
+	}
+
+	set := flag.NewFlagSet("test", 0)
+	for _, f := range flags {
+		f.Apply(set)
+	}
+
+	e := set.Parse([]string{"--required", "foo"})
+	if e != nil {
+		t.Errorf("Expected no error parsing but there was one: %s", e)
+	}
+
+	err := checkRequiredFlags(flags, set)
+	if err != nil {
+		t.Error("Expected flag parsing to be successful")
+	}
+}
+
+func TestContext_CheckRequiredFlagsFailure(t *testing.T) {
+	flags := []Flag{
+		StringFlag{
+			Name:     "required",
+			Required: true,
+		},
+		StringFlag{
+			Name: "optional",
+		},
+	}
+
+	set := flag.NewFlagSet("test", 0)
+	for _, f := range flags {
+		f.Apply(set)
+	}
+
+	e := set.Parse([]string{"--optional", "foo"})
+	if e != nil {
+		t.Errorf("Expected no error parsing but there was one: %s", e)
+	}
+
+	err := checkRequiredFlags(flags, set)
+	if err == nil {
+		t.Error("Expected flag parsing to be unsuccessful")
+	}
+}