You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

137 lines
3.1 KiB

package cli
import (
"flag"
"fmt"
"os"
"strings"
)
// BashCompletionFlag - This flag enables bash-completion for all commands and subcommands
// it is hidden by default
var BashCompletionFlag = BoolFlag{
Name: "generate-bash-completion",
Hide: true,
}
// VersionFlag - This flag prints the version for the application
var VersionFlag = BoolFlag{
Name: "version, v",
Usage: "print the version",
}
// HelpFlay - This flag 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) it is hidden by default
var HelpFlag = BoolFlag{
Name: "help, h",
Usage: "show help",
Hide: true,
}
// Flag is a common interface related to parsing flags in cli.
// For more advanced flag parsing techniques, it is recomended that
// this interface be implemented.
type Flag interface {
fmt.Stringer
// Apply Flag settings to the given flag set
Apply(*flag.FlagSet)
getName() string
isNotHidden() bool
}
func flagSet(name string, flags []Flag) *flag.FlagSet {
set := flag.NewFlagSet(name, flag.ContinueOnError)
for _, f := range flags {
f.Apply(set)
}
return set
}
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
}
// GenericFlag is the flag type for types implementing Generic
type GenericFlag struct {
Name string
Value Generic
Usage string
EnvVar string
Hide bool
}
// String returns the string representation of the generic flag to display the
// help text to the user (uses the String() method of the generic flag to show
// the value)
func (f GenericFlag) String() string {
return withEnvHint(f.EnvVar, fmt.Sprintf("%s%s \"%v\"\t%v", prefixFor(f.Name), f.Name, f.Value, f.Usage))
}
// Apply 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) Apply(set *flag.FlagSet) {
val := f.Value
if f.EnvVar != "" {
for _, envVar := range strings.Split(f.EnvVar, ",") {
envVar = strings.TrimSpace(envVar)
if envVal := os.Getenv(envVar); envVal != "" {
val.Set(envVal)
break
}
}
}
eachName(f.Name, func(name string) {
set.Var(f.Value, name, f.Usage)
})
}
func (f GenericFlag) getName() string {
return f.Name
}
func (f GenericFlag) isNotHidden() bool {
return !f.Hide
}
func prefixFor(name string) (prefix string) {
if len(name) == 1 {
prefix = "-"
} else {
prefix = "--"
}
return
}
func prefixedNames(fullName string) (prefixed string) {
parts := strings.Split(fullName, ",")
for i, name := range parts {
name = strings.Trim(name, " ")
prefixed += prefixFor(name) + name
if i < len(parts)-1 {
prefixed += ", "
}
}
return
}
func withEnvHint(envVar, str string) string {
envText := ""
if envVar != "" {
envText = fmt.Sprintf(" [$%s]", strings.Join(strings.Split(envVar, ","), ", $"))
}
return str + envText
}