package cmd import ( "fmt" "io" "os" "strings" "text/tabwriter" "github.com/urfave/cli" ) func createDNSHelp() cli.Command { return cli.Command{ Name: "dnshelp", Usage: "Shows additional help for the '--dns' global option", Action: dnsHelp, Flags: []cli.Flag{ cli.StringFlag{ Name: "code, c", Usage: fmt.Sprintf("DNS code: %s", allDNSCodes()), }, }, } } func dnsHelp(ctx *cli.Context) error { code := ctx.String("code") if code == "" { w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0) ew := &errWriter{w: w} ew.writeln(`Credentials for DNS providers must be passed through environment variables.`) ew.writeln() ew.writeln(`To display the documentation for a DNS providers:`) ew.writeln() ew.writeln("\t$ lego dnshelp -c code") ew.writeln() ew.writeln("All DNS codes:") ew.writef("\t%s\n", allDNSCodes()) ew.writeln() ew.writeln("More information: https://go-acme.github.io/lego/dns") if ew.err != nil { return ew.err } return w.Flush() } return displayDNSHelp(strings.ToLower(code)) } type errWriter struct { w io.Writer err error } func (ew *errWriter) writeln(a ...interface{}) { if ew.err != nil { return } _, ew.err = fmt.Fprintln(ew.w, a...) } func (ew *errWriter) writef(format string, a ...interface{}) { if ew.err != nil { return } _, ew.err = fmt.Fprintf(ew.w, format, a...) }