GopherCon 2019 - Design Command-Line Tools that People Love

conference, golang, gophercon2019, notes

These are some notes from my experiences at the GopherCon 2019. I don’t expect these will be laid out in any particularly useful way; I am mostly taking them so I can remember some of the bits I found most useful in the future.

  • Presenter likes subcommands that read like sentences (cmd verb noun [name] [–flags])

    • Saying things out loud and it sounding good is a nice guide
  • Follow precendent in naming when it makes sense (easier transitions)

  • Always machine output format option (json)

  • Default human first output

  • Multiple positional args only when order doesn’t matter

  • go-humanize for relative datetimes, byte sizes, plurals, etc

  • Good help text (examples)

  • Aliases / shortcuts / good defaults are nice for humans (e.g., skip verbs or nouns when it makes sense)

  • Task-bundled commands are nice for humans

  • Needs high quality code behind it

    • Reliable
    • Good error messages / help
    • Maintainable and testable
  • Recommends cobra

    • But still have to think about testing etc
  • Design package(s), not just a cli

  • Pro-tip: keep viper isolated

  • cobra helper PreRunE – called after flags but before run