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/
help.go
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/
help.go
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// Copyright 2014 CoreOS, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"flag"
"fmt"
"strings"
"text/template"
"github.com/coreos/fleet/version"
)
const (
// used to indicate flag usage should not be printed
hidden = "hidden"
)
var (
cmdHelp = &Command{
Name: "help",
Summary: "Show a list of commands or help for one command",
Usage: "[COMMAND]",
Description: "Show a list of commands or detailed help for one command",
Run: runHelp,
}
globalUsageTemplate *template.Template
commandUsageTemplate *template.Template
templFuncs = template.FuncMap{
"descToLines": func(s string) []string {
// trim leading/trailing whitespace and split into slice of lines
return strings.Split(strings.Trim(s, "\n\t "), "\n")
},
"printOption": func(name, defvalue, usage string) string {
if usage == hidden {
return ""
}
prefix := "--"
if len(name) == 1 {
prefix = "-"
}
return fmt.Sprintf("\n\t%s%s=%s\t%s", prefix, name, defvalue, usage)
},
}
)
func init() {
globalUsageTemplate = template.Must(template.New("global_usage").Funcs(templFuncs).Parse(`
NAME:
{{printf "\t%s - %s" .Executable .Description}}
USAGE:
{{printf "\t%s" .Executable}} [global options] <command> [command options] [arguments...]
VERSION:
{{printf "\t%s" .Version}}
COMMANDS:{{range .Commands}}
{{printf "\t%s\t%s" .Name .Summary}}{{end}}
GLOBAL OPTIONS:{{range .Flags}}{{printOption .Name .DefValue .Usage}}{{end}}
Global options can also be configured via upper-case environment variables prefixed with "FLEETCTL_"
For example, "some-flag" => "FLEETCTL_SOME_FLAG"
Run "{{.Executable}} help <command>" for more details on a specific command.
`[1:]))
commandUsageTemplate = template.Must(template.New("command_usage").Funcs(templFuncs).Parse(`
NAME:
{{printf "\t%s - %s" .Cmd.Name .Cmd.Summary}}
USAGE:
{{printf "\t%s %s %s" .Executable .Cmd.Name .Cmd.Usage}}
DESCRIPTION:
{{range $line := descToLines .Cmd.Description}}{{printf "\t%s" $line}}
{{end}}
{{if .CmdFlags}}OPTIONS:{{range .CmdFlags}}
{{printOption .Name .DefValue .Usage}}{{end}}
{{end}}For help on global options run "{{.Executable}} help"
`[1:]))
}
func runHelp(args []string) (exit int) {
if len(args) < 1 {
printGlobalUsage()
return
}
var cmd *Command
for _, c := range commands {
if c.Name == args[0] {
cmd = c
break
}
}
if cmd == nil {
stderr("Unrecognized command: %s", args[0])
return 1
}
printCommandUsage(cmd)
return
}
func printGlobalUsage() {
globalUsageTemplate.Execute(out, struct {
Executable string
Commands []*Command
Flags []*flag.Flag
Description string
Version string
}{
cliName,
commands,
getAllFlags(),
cliDescription,
version.Version,
})
out.Flush()
}
func printCommandUsage(cmd *Command) {
commandUsageTemplate.Execute(out, struct {
Executable string
Cmd *Command
CmdFlags []*flag.Flag
}{
cliName,
cmd,
getFlags(&cmd.Flags),
})
out.Flush()
}