package cli
|
|
import (
|
"bytes"
|
"fmt"
|
"log"
|
"sort"
|
"strings"
|
)
|
|
// HelpFunc is the type of the function that is responsible for generating
|
// the help output when the CLI must show the general help text.
|
type HelpFunc func(map[string]CommandFactory) string
|
|
// BasicHelpFunc generates some basic help output that is usually good enough
|
// for most CLI applications.
|
func BasicHelpFunc(app string) HelpFunc {
|
return func(commands map[string]CommandFactory) string {
|
var buf bytes.Buffer
|
buf.WriteString(fmt.Sprintf(
|
"Usage: %s [--version] [--help] <command> [<args>]\n\n",
|
app))
|
buf.WriteString("Available commands are:\n")
|
|
// Get the list of keys so we can sort them, and also get the maximum
|
// key length so they can be aligned properly.
|
keys := make([]string, 0, len(commands))
|
maxKeyLen := 0
|
for key := range commands {
|
if len(key) > maxKeyLen {
|
maxKeyLen = len(key)
|
}
|
|
keys = append(keys, key)
|
}
|
sort.Strings(keys)
|
|
for _, key := range keys {
|
commandFunc, ok := commands[key]
|
if !ok {
|
// This should never happen since we JUST built the list of
|
// keys.
|
panic("command not found: " + key)
|
}
|
|
command, err := commandFunc()
|
if err != nil {
|
log.Printf("[ERR] cli: Command '%s' failed to load: %s",
|
key, err)
|
continue
|
}
|
|
key = fmt.Sprintf("%s%s", key, strings.Repeat(" ", maxKeyLen-len(key)))
|
buf.WriteString(fmt.Sprintf(" %s %s\n", key, command.Synopsis()))
|
}
|
|
return buf.String()
|
}
|
}
|
|
// FilteredHelpFunc will filter the commands to only include the keys
|
// in the include parameter.
|
func FilteredHelpFunc(include []string, f HelpFunc) HelpFunc {
|
return func(commands map[string]CommandFactory) string {
|
set := make(map[string]struct{})
|
for _, k := range include {
|
set[k] = struct{}{}
|
}
|
|
filtered := make(map[string]CommandFactory)
|
for k, f := range commands {
|
if _, ok := set[k]; ok {
|
filtered[k] = f
|
}
|
}
|
|
return f(filtered)
|
}
|
}
|
