| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 ( |
| "fmt" |
| "os" |
| ) |
| |
| type command interface { |
| usage() |
| run(args []string) |
| } |
| |
| var ( |
| cmds = map[string]command{} |
| ) |
| |
| func registerCommand(name string, cmd command) { |
| if cmd == nil { |
| panic("empty command") |
| } |
| |
| _, ok := cmds[name] |
| if ok { |
| panic(fmt.Sprintf("%s command existed", name)) |
| } |
| |
| cmds[name] = cmd |
| } |
| |
| func usage() { |
| println(os.Args[0] + " commandName [...]") |
| for _, cmd := range cmds { |
| cmd.usage() |
| } |
| } |
| |
| // go run *.go [command name] [command args] |
| func main() { |
| if len(os.Args) < 2 { |
| println("error:lack cmd name\n") |
| usage() |
| return |
| } |
| |
| name := os.Args[1] |
| cmd, ok := cmds[name] |
| if !ok { |
| fmt.Printf("command %s is not supported\n", name) |
| usage() |
| return |
| } |
| |
| cmd.run(os.Args[2:]) |
| } |