136 lines
2.9 KiB
Go
136 lines
2.9 KiB
Go
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package main
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import (
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"flag"
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"fmt"
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"os"
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"strings"
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"text/tabwriter"
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"text/template"
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)
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var (
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cmdHelp = &command{
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Name: "help",
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Summary: "Show a list of commands or help for one command",
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Usage: "[COMMAND]",
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Run: runHelp,
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}
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globalUsageTemplate *template.Template
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commandUsageTemplate *template.Template
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templFuncs = template.FuncMap{
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"descToLines": func(s string) []string {
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// trim leading/trailing whitespace and split into slice of lines
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return strings.Split(strings.Trim(s, "\n\t "), "\n")
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},
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"printOption": func(name, defvalue, usage string) string {
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prefix := "--"
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if len(name) == 1 {
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prefix = "-"
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}
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return fmt.Sprintf("\n\t%s%s=%s\t%s", prefix, name, defvalue, usage)
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},
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}
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tabOut *tabwriter.Writer
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)
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func init() {
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tabOut = tabwriter.NewWriter(os.Stdout, 0, 8, 1, '\t', 0)
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commands = append(commands, cmdHelp)
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globalUsageTemplate = template.Must(template.New("global_usage").Funcs(templFuncs).Parse(`
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NAME:
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{{printf "\t%s - %s" .Executable .Description}}
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USAGE:
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{{printf "\t%s" .Executable}} [global options] <command> [command options] [arguments...]
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COMMANDS:{{range .Commands}}
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{{printf "\t%s\t%s" .Name .Summary}}{{end}}
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GLOBAL OPTIONS:{{range .Flags}}{{printOption .Name .DefValue .Usage}}{{end}}
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Global options can also be configured via upper-case environment variables prefixed with "DEXCTL_"
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For example, "some-flag" => "DEXCTL_SOME_FLAG"
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Run "{{.Executable}} help <command>" for more details on a specific command.
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`[1:]))
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commandUsageTemplate = template.Must(template.New("command_usage").Funcs(templFuncs).Parse(`
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NAME:
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{{printf "\t%s - %s" .Cmd.Name .Cmd.Summary}}
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USAGE:
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{{printf "\t%s %s %s" .Executable .Cmd.Name .Cmd.Usage}}
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DESCRIPTION:
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{{range $line := descToLines .Cmd.Description}}{{printf "\t%s" $line}}
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{{end}}
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{{if .CmdFlags}}OPTIONS:{{range .CmdFlags}}
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{{printOption .Name .DefValue .Usage}}{{end}}
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{{end}}For help on global options run "{{.Executable}} help"
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`[1:]))
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}
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func runHelp(args []string) (exit int) {
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if len(args) < 1 {
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printGlobalUsage()
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return
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}
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var cmd *command
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for _, c := range commands {
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if c.Name == args[0] {
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cmd = c
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break
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}
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}
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if cmd == nil {
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stderr("Unrecognized command: %s", args[0])
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return 1
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}
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printCommandUsage(cmd)
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return
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}
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func printGlobalUsage() {
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globalUsageTemplate.Execute(tabOut, struct {
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Executable string
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Commands []*command
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Flags []*flag.Flag
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Description string
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}{
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cliName,
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commands,
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getFlags(globalFS),
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cliDescription,
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})
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tabOut.Flush()
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}
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func printCommandUsage(cmd *command) {
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commandUsageTemplate.Execute(tabOut, struct {
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Executable string
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Cmd *command
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CmdFlags []*flag.Flag
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}{
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cliName,
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cmd,
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getFlags(&cmd.Flags),
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})
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tabOut.Flush()
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}
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func getFlags(flagset *flag.FlagSet) (flags []*flag.Flag) {
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flags = make([]*flag.Flag, 0)
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flagset.VisitAll(func(f *flag.Flag) {
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flags = append(flags, f)
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})
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return
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}
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