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|
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)
}
}
|
