urfave-cli/flag.go
rliebz 11d45572f9 Export funcs to configure flag prefix/env hints
This will allow users to customize the prefix section or env hint
section of the flag entries in the help menu without having to
reimplement the rest of the logic required in defining FlagStringer.
2017-09-18 00:00:27 -04:00

808 lines
20 KiB
Go

package cli
import (
"flag"
"fmt"
"reflect"
"runtime"
"strconv"
"strings"
"syscall"
"time"
)
const defaultPlaceholder = "value"
// BashCompletionFlag enables bash-completion for all commands and subcommands
var BashCompletionFlag Flag = BoolFlag{
Name: "generate-bash-completion",
Hidden: true,
}
// VersionFlag prints the version for the application
var VersionFlag Flag = BoolFlag{
Name: "version, v",
Usage: "print the version",
}
// HelpFlag prints the help for all commands and subcommands
// Set to the zero value (BoolFlag{}) to disable flag -- keeps subcommand
// unless HideHelp is set to true)
var HelpFlag Flag = BoolFlag{
Name: "help, h",
Usage: "show help",
}
// FlagStringer converts a flag definition to a string. This is used by help
// to display a flag.
var FlagStringer FlagStringFunc = stringifyFlag
// FlagNamePrefixer converts a full flag name and its placeholder into the help
// message flag prefix. This is used by the default FlagStringer.
var FlagNamePrefixer FlagNamePrefixFunc = prefixedNames
// FlagEnvHinter annotates flag help message with the environment variable
// details. This is used by the default FlagStringer.
var FlagEnvHinter FlagEnvHintFunc = withEnvHint
// FlagsByName is a slice of Flag.
type FlagsByName []Flag
func (f FlagsByName) Len() int {
return len(f)
}
func (f FlagsByName) Less(i, j int) bool {
return f[i].GetName() < f[j].GetName()
}
func (f FlagsByName) Swap(i, j int) {
f[i], f[j] = f[j], f[i]
}
// Flag is a common interface related to parsing flags in cli.
// For more advanced flag parsing techniques, it is recommended that
// this interface be implemented.
type Flag interface {
fmt.Stringer
// Apply Flag settings to the given flag set
Apply(*flag.FlagSet)
GetName() string
}
// errorableFlag is an interface that allows us to return errors during apply
// it allows flags defined in this library to return errors in a fashion backwards compatible
// TODO remove in v2 and modify the existing Flag interface to return errors
type errorableFlag interface {
Flag
ApplyWithError(*flag.FlagSet) error
}
func flagSet(name string, flags []Flag) (*flag.FlagSet, error) {
set := flag.NewFlagSet(name, flag.ContinueOnError)
for _, f := range flags {
//TODO remove in v2 when errorableFlag is removed
if ef, ok := f.(errorableFlag); ok {
if err := ef.ApplyWithError(set); err != nil {
return nil, err
}
} else {
f.Apply(set)
}
}
return set, nil
}
func eachName(longName string, fn func(string)) {
parts := strings.Split(longName, ",")
for _, name := range parts {
name = strings.Trim(name, " ")
fn(name)
}
}
// Generic is a generic parseable type identified by a specific flag
type Generic interface {
Set(value string) error
String() string
}
// Apply takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
// Ignores parsing errors
func (f GenericFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError takes the flagset and calls Set on the generic flag with the value
// provided by the user for parsing by the flag
func (f GenericFlag) ApplyWithError(set *flag.FlagSet) error {
val := f.Value
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
if err := val.Set(envVal); err != nil {
return fmt.Errorf("could not parse %s as value for flag %s: %s", envVal, f.Name, err)
}
break
}
}
}
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
return nil
}
// StringSlice is an opaque type for []string to satisfy flag.Value and flag.Getter
type StringSlice []string
// Set appends the string value to the list of values
func (f *StringSlice) Set(value string) error {
*f = append(*f, value)
return nil
}
// String returns a readable representation of this value (for usage defaults)
func (f *StringSlice) String() string {
return fmt.Sprintf("%s", *f)
}
// Value returns the slice of strings set by this flag
func (f *StringSlice) Value() []string {
return *f
}
// Get returns the slice of strings set by this flag
func (f *StringSlice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringSliceFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f StringSliceFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
newVal := &StringSlice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as string value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
break
}
}
}
eachName(f.Name, func(name string) {
if f.Value == nil {
f.Value = &StringSlice{}
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// IntSlice is an opaque type for []int to satisfy flag.Value and flag.Getter
type IntSlice []int
// Set parses the value into an integer and appends it to the list of values
func (f *IntSlice) Set(value string) error {
tmp, err := strconv.Atoi(value)
if err != nil {
return err
}
*f = append(*f, tmp)
return nil
}
// String returns a readable representation of this value (for usage defaults)
func (f *IntSlice) String() string {
return fmt.Sprintf("%#v", *f)
}
// Value returns the slice of ints set by this flag
func (f *IntSlice) Value() []int {
return *f
}
// Get returns the slice of ints set by this flag
func (f *IntSlice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntSliceFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f IntSliceFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
newVal := &IntSlice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as int slice value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
break
}
}
}
eachName(f.Name, func(name string) {
if f.Value == nil {
f.Value = &IntSlice{}
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// Int64Slice is an opaque type for []int to satisfy flag.Value and flag.Getter
type Int64Slice []int64
// Set parses the value into an integer and appends it to the list of values
func (f *Int64Slice) Set(value string) error {
tmp, err := strconv.ParseInt(value, 10, 64)
if err != nil {
return err
}
*f = append(*f, tmp)
return nil
}
// String returns a readable representation of this value (for usage defaults)
func (f *Int64Slice) String() string {
return fmt.Sprintf("%#v", *f)
}
// Value returns the slice of ints set by this flag
func (f *Int64Slice) Value() []int64 {
return *f
}
// Get returns the slice of ints set by this flag
func (f *Int64Slice) Get() interface{} {
return *f
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64SliceFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f Int64SliceFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
newVal := &Int64Slice{}
for _, s := range strings.Split(envVal, ",") {
s = strings.TrimSpace(s)
if err := newVal.Set(s); err != nil {
return fmt.Errorf("could not parse %s as int64 slice value for flag %s: %s", envVal, f.Name, err)
}
}
f.Value = newVal
break
}
}
}
eachName(f.Name, func(name string) {
if f.Value == nil {
f.Value = &Int64Slice{}
}
set.Var(f.Value, name, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f BoolFlag) ApplyWithError(set *flag.FlagSet) error {
val := false
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
if envVal == "" {
val = false
break
}
envValBool, err := strconv.ParseBool(envVal)
if err != nil {
return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
}
val = envValBool
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.BoolVar(f.Destination, name, val, f.Usage)
return
}
set.Bool(name, val, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f BoolTFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f BoolTFlag) ApplyWithError(set *flag.FlagSet) error {
val := true
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
if envVal == "" {
val = false
break
}
envValBool, err := strconv.ParseBool(envVal)
if err != nil {
return fmt.Errorf("could not parse %s as bool value for flag %s: %s", envVal, f.Name, err)
}
val = envValBool
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.BoolVar(f.Destination, name, val, f.Usage)
return
}
set.Bool(name, val, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f StringFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f StringFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
f.Value = envVal
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.StringVar(f.Destination, name, f.Value, f.Usage)
return
}
set.String(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f IntFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f IntFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseInt(envVal, 0, 64)
if err != nil {
return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
}
f.Value = int(envValInt)
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.IntVar(f.Destination, name, f.Value, f.Usage)
return
}
set.Int(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Int64Flag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f Int64Flag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseInt(envVal, 0, 64)
if err != nil {
return fmt.Errorf("could not parse %s as int value for flag %s: %s", envVal, f.Name, err)
}
f.Value = envValInt
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.Int64Var(f.Destination, name, f.Value, f.Usage)
return
}
set.Int64(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f UintFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f UintFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseUint(envVal, 0, 64)
if err != nil {
return fmt.Errorf("could not parse %s as uint value for flag %s: %s", envVal, f.Name, err)
}
f.Value = uint(envValInt)
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.UintVar(f.Destination, name, f.Value, f.Usage)
return
}
set.Uint(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Uint64Flag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f Uint64Flag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValInt, err := strconv.ParseUint(envVal, 0, 64)
if err != nil {
return fmt.Errorf("could not parse %s as uint64 value for flag %s: %s", envVal, f.Name, err)
}
f.Value = uint64(envValInt)
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.Uint64Var(f.Destination, name, f.Value, f.Usage)
return
}
set.Uint64(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f DurationFlag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f DurationFlag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValDuration, err := time.ParseDuration(envVal)
if err != nil {
return fmt.Errorf("could not parse %s as duration for flag %s: %s", envVal, f.Name, err)
}
f.Value = envValDuration
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.DurationVar(f.Destination, name, f.Value, f.Usage)
return
}
set.Duration(name, f.Value, f.Usage)
})
return nil
}
// Apply populates the flag given the flag set and environment
// Ignores errors
func (f Float64Flag) Apply(set *flag.FlagSet) {
f.ApplyWithError(set)
}
// ApplyWithError populates the flag given the flag set and environment
func (f Float64Flag) ApplyWithError(set *flag.FlagSet) error {
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
envValFloat, err := strconv.ParseFloat(envVal, 10)
if err != nil {
return fmt.Errorf("could not parse %s as float64 value for flag %s: %s", envVal, f.Name, err)
}
f.Value = float64(envValFloat)
break
}
}
}
eachName(f.Name, func(name string) {
if f.Destination != nil {
set.Float64Var(f.Destination, name, f.Value, f.Usage)
return
}
set.Float64(name, f.Value, f.Usage)
})
return nil
}
func visibleFlags(fl []Flag) []Flag {
visible := []Flag{}
for _, flag := range fl {
field := flagValue(flag).FieldByName("Hidden")
if !field.IsValid() || !field.Bool() {
visible = append(visible, flag)
}
}
return visible
}
func prefixFor(name string) (prefix string) {
if len(name) == 1 {
prefix = "-"
} else {
prefix = "--"
}
return
}
// Returns the placeholder, if any, and the unquoted usage string.
func unquoteUsage(usage string) (string, string) {
for i := 0; i < len(usage); i++ {
if usage[i] == '`' {
for j := i + 1; j < len(usage); j++ {
if usage[j] == '`' {
name := usage[i+1 : j]
usage = usage[:i] + name + usage[j+1:]
return name, usage
}
}
break
}
}
return "", usage
}
func prefixedNames(fullName, placeholder string) string {
var prefixed string
parts := strings.Split(fullName, ",")
for i, name := range parts {
name = strings.Trim(name, " ")
prefixed += prefixFor(name) + name
if placeholder != "" {
prefixed += " " + placeholder
}
if i < len(parts)-1 {
prefixed += ", "
}
}
return prefixed
}
func withEnvHint(envVar, str string) string {
envText := ""
if envVar != "" {
prefix := "$"
suffix := ""
sep := ", $"
if runtime.GOOS == "windows" {
prefix = "%"
suffix = "%"
sep = "%, %"
}
envText = fmt.Sprintf(" [%s%s%s]", prefix, strings.Join(strings.Split(envVar, ","), sep), suffix)
}
return str + envText
}
func flagValue(f Flag) reflect.Value {
fv := reflect.ValueOf(f)
for fv.Kind() == reflect.Ptr {
fv = reflect.Indirect(fv)
}
return fv
}
func stringifyFlag(f Flag) string {
fv := flagValue(f)
switch f.(type) {
case IntSliceFlag:
return FlagEnvHinter(fv.FieldByName("EnvVar").String(),
stringifyIntSliceFlag(f.(IntSliceFlag)))
case Int64SliceFlag:
return FlagEnvHinter(fv.FieldByName("EnvVar").String(),
stringifyInt64SliceFlag(f.(Int64SliceFlag)))
case StringSliceFlag:
return FlagEnvHinter(fv.FieldByName("EnvVar").String(),
stringifyStringSliceFlag(f.(StringSliceFlag)))
}
placeholder, usage := unquoteUsage(fv.FieldByName("Usage").String())
needsPlaceholder := false
defaultValueString := ""
if val := fv.FieldByName("Value"); val.IsValid() {
needsPlaceholder = true
defaultValueString = fmt.Sprintf(" (default: %v)", val.Interface())
if val.Kind() == reflect.String && val.String() != "" {
defaultValueString = fmt.Sprintf(" (default: %q)", val.String())
}
}
if defaultValueString == " (default: )" {
defaultValueString = ""
}
if needsPlaceholder && placeholder == "" {
placeholder = defaultPlaceholder
}
usageWithDefault := strings.TrimSpace(fmt.Sprintf("%s%s", usage, defaultValueString))
return FlagEnvHinter(fv.FieldByName("EnvVar").String(),
fmt.Sprintf("%s\t%s", FlagNamePrefixer(fv.FieldByName("Name").String(), placeholder), usageWithDefault))
}
func stringifyIntSliceFlag(f IntSliceFlag) string {
defaultVals := []string{}
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, i := range f.Value.Value() {
defaultVals = append(defaultVals, fmt.Sprintf("%d", i))
}
}
return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}
func stringifyInt64SliceFlag(f Int64SliceFlag) string {
defaultVals := []string{}
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, i := range f.Value.Value() {
defaultVals = append(defaultVals, fmt.Sprintf("%d", i))
}
}
return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}
func stringifyStringSliceFlag(f StringSliceFlag) string {
defaultVals := []string{}
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, s := range f.Value.Value() {
if len(s) > 0 {
defaultVals = append(defaultVals, fmt.Sprintf("%q", s))
}
}
}
return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}
func stringifySliceFlag(usage, name string, defaultVals []string) string {
placeholder, usage := unquoteUsage(usage)
if placeholder == "" {
placeholder = defaultPlaceholder
}
defaultVal := ""
if len(defaultVals) > 0 {
defaultVal = fmt.Sprintf(" (default: %s)", strings.Join(defaultVals, ", "))
}
usageWithDefault := strings.TrimSpace(fmt.Sprintf("%s%s", usage, defaultVal))
return fmt.Sprintf("%s\t%s", FlagNamePrefixer(name, placeholder), usageWithDefault)
}