| 129 | `)) |
| 130 | |
| 131 | func displayProgramUsage(components Components) func() { |
| 132 | return func() { |
| 133 | // Structure program usage sections |
| 134 | type programUsage struct { |
| 135 | Build string |
| 136 | ExecName string |
| 137 | Defaults string |
| 138 | Components Components |
| 139 | } |
| 140 | |
| 141 | // Capture command argument defaults |
| 142 | var defaultsBuilder strings.Builder |
| 143 | flag.CommandLine.SetOutput(&defaultsBuilder) |
| 144 | flag.PrintDefaults() |
| 145 | |
| 146 | // Inject program usage data into message template |
| 147 | if err := programUsageTemplate.Execute(os.Stderr, &programUsage{ |
| 148 | ExecName: os.Args[0], |
| 149 | Defaults: defaultsBuilder.String(), |
| 150 | Components: components, |
| 151 | }); err != nil { |
| 152 | panic(err) |
| 153 | } |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | // checkHostPort checks that addr ("host:port" format) is a free tcp port |
| 158 | // suitable for binding a listener. |