Skip to content
Permalink
Branch: master
Find file Copy path
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
347 lines (293 sloc) 8.33 KB
package cli
import (
"flag"
"fmt"
"io/ioutil"
"reflect"
"runtime"
"strconv"
"strings"
"syscall"
)
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
// FlagFileHinter annotates flag help message with the environment variable
// details. This is used by the default FlagStringer.
var FlagFileHinter FlagFileHintFunc = withFileHint
// 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 lexicographicLess(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
}
// RequiredFlag is an interface that allows us to mark flags as required
// it allows flags required flags to be backwards compatible with the Flag interface
type RequiredFlag interface {
Flag
IsRequired() bool
}
// DocGenerationFlag is an interface that allows documentation generation for the flag
type DocGenerationFlag interface {
Flag
// TakesValue returns true of the flag takes a value, otherwise false
TakesValue() bool
// GetUsage returns the usage string for the flag
GetUsage() string
// GetValue returns the flags value as string representation and an empty
// string if the flag takes no value at all.
GetValue() 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)
}
}
set.SetOutput(ioutil.Discard)
return set, nil
}
func eachName(longName string, fn func(string)) {
parts := strings.Split(longName, ",")
for _, name := range parts {
name = strings.Trim(name, " ")
fn(name)
}
}
func visibleFlags(fl []Flag) []Flag {
var visible []Flag
for _, f := range fl {
field := flagValue(f).FieldByName("Hidden")
if !field.IsValid() || !field.Bool() {
visible = append(visible, f)
}
}
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 = " [" + prefix + strings.Join(strings.Split(envVar, ","), sep) + suffix + "]"
}
return str + envText
}
func withFileHint(filePath, str string) string {
fileText := ""
if filePath != "" {
fileText = fmt.Sprintf(" [%s]", filePath)
}
return str + fileText
}
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 FlagFileHinter(
fv.FieldByName("FilePath").String(),
FlagEnvHinter(
fv.FieldByName("EnvVar").String(),
stringifyIntSliceFlag(f.(IntSliceFlag)),
),
)
case Int64SliceFlag:
return FlagFileHinter(
fv.FieldByName("FilePath").String(),
FlagEnvHinter(
fv.FieldByName("EnvVar").String(),
stringifyInt64SliceFlag(f.(Int64SliceFlag)),
),
)
case StringSliceFlag:
return FlagFileHinter(
fv.FieldByName("FilePath").String(),
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(usage + defaultValueString)
return FlagFileHinter(
fv.FieldByName("FilePath").String(),
FlagEnvHinter(
fv.FieldByName("EnvVar").String(),
FlagNamePrefixer(fv.FieldByName("Name").String(), placeholder)+"\t"+usageWithDefault,
),
)
}
func stringifyIntSliceFlag(f IntSliceFlag) string {
var defaultVals []string
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, i := range f.Value.Value() {
defaultVals = append(defaultVals, strconv.Itoa(i))
}
}
return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}
func stringifyInt64SliceFlag(f Int64SliceFlag) string {
var defaultVals []string
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, i := range f.Value.Value() {
defaultVals = append(defaultVals, strconv.FormatInt(i, 10))
}
}
return stringifySliceFlag(f.Usage, f.Name, defaultVals)
}
func stringifyStringSliceFlag(f StringSliceFlag) string {
var defaultVals []string
if f.Value != nil && len(f.Value.Value()) > 0 {
for _, s := range f.Value.Value() {
if len(s) > 0 {
defaultVals = append(defaultVals, strconv.Quote(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(usage + defaultVal)
return FlagNamePrefixer(name, placeholder) + "\t" + usageWithDefault
}
func flagFromFileEnv(filePath, envName string) (val string, ok bool) {
for _, envVar := range strings.Split(envName, ",") {
envVar = strings.TrimSpace(envVar)
if envVal, ok := syscall.Getenv(envVar); ok {
return envVal, true
}
}
for _, fileVar := range strings.Split(filePath, ",") {
if data, err := ioutil.ReadFile(fileVar); err == nil {
return string(data), true
}
}
return "", false
}
You can’t perform that action at this time.