Fang, the CLI Starter Kit

147 points by bewuethr 333 days ago | 32 comments

csomar 333 days ago |

I’ve been maintaining rust-starter[!] for quite sometime now. It is kind of the equivalent of fang but for Rust. It uses Clap which is the equivalent of Cobra; though I don’t think Clap has the same kind of fancy output?

Throughout these years, I have found that cross-compiling is the most challenging part of creating a CLI. When you are building a web back-end, you control the execution environment (usually linux). For CLIs, your users could be on Linux, macOS or Windows. You need to get three x2 binaries (so a total of 6) to have a fair coverage.

I’ve tried cross, but for Windows and macOS you need licenses. There is no straightforward way to give your users Docker images and have them running in a few commands. You can compile on GitHub action machines, but that’s a very slow feedback loop. I wonder if things are better in Go land.

!: https://github.com/rust-starter/rust-starter

neomantra 333 days ago | |

Golang itself bundles a toolchain and can cross compile to a many target OSes and architectures. I use Goreleaser [1] to create GitHub releases, Homebrew packages, Docker images, and Linux packages. Goreleaser Pro can also create MSI packages.

ETA since I just saw Christian chime in: the Goreleaser author works at Charm.sh =)

[1] https://goreleaser.com

christianrocha 333 days ago | | |

GoReleaser is indeed an awesome tool and we use it for every applicable project.

And actually Carlos, who builds GoReleaser, is the true author of Fang and took it from concept to execution.

christianrocha 333 days ago | |

I feel your pain. That said, cross compiling from Go is pretty trivial, as long as everything is pure Go, which it most often is. That’s one if the reasons we invested in jt.

(Hello from Charm! I’m one of the authors of this library.)

threemux 333 days ago | |

Wow TIL cross compilation is a bit of a pain in Rust. I assumed it was as easy as Go. I can confirm as long as you're using pure Go (no cgo), it's as easy as setting $GOOS and $GOARCH appropriately.

paulddraper 333 days ago | | |

The difficulty is due to Rust dynamically linking and Go statically linking. The former requires the system libs.

That said, I am unfamiliar with any licensing for Windows builds.

MacOS has some niche (usually discarded) technicalities like you can only use the SDK on Apple hardware.

rmac 333 days ago | |

I looked into how rust does does it for rustup, and they have a pretty amazing set of gh actions to build for their architectures, I can't find the GH link now tho

for speed you can look for vendors like https://depot.dev/

mootoday 333 days ago | |

This is great, lots I learned by looking at your code and the dependencies you use!

I started a similar thing, although not as feature-rich as yours. My goal was to follow CLI best practices and add all the boilerplate one needs to build a Rust CLI.

https://github.com/mootoday/cli-template

masfuerte 333 days ago | |

I configure github actions to build each version in its natural habitat.

Though my motivation for this was getting the builds off my machine. I didn't want to be shipping binaries I had built locally.

johnisgood 333 days ago |

I just ran across "gum"[1] from charmbracelet which I intend to use! I just want to replace dialog. I came across whiptail, too, but gum seems nicer.

They have a TUI framework, too, among a lot of other related things. Some of their projects are Go libraries, some are a CLI tool, such as gum.

[1] https://github.com/charmbracelet/gum

nodesocket 333 days ago | |

Gum looks awesome. Gonna keep it in-mind next time I need to write a shell CLI.

bbkane 333 days ago |

It would be really cool if Fang could generate a TUI form for your app with https://github.com/charmbracelet/huh (by the same org). Is something like that on the roadmap?

I've wanted to do TUI form generation for my own CLI framework since 2023 ( https://github.com/bbkane/warg/issues/71 ), but I still haven't gotten around to it

jmsdnns 333 days ago |

This is awesome! Love the work the charm bracelet team is doing.

christianrocha 333 days ago | |

Thank you for the very kind words. Hello from Charm!

jonpalmisc 333 days ago |

Stubborn complaint (and maybe a hot take): I dislike CLIs that try to be overly pretty. I don't receive any tangible benefit as the user from the "fancy" (their words) help output. I'd much rather simple plain text output that looks like all the other tools I already use.

aranw 333 days ago |

It's probably more accurate to say it's a Go Cobra CLI Starter Kit rather just a generic CLI Starter kit. I personally find Cobra bit OTT and bloated and try to avoid it where I can but this could be a nice starter point for my own similar library to suit my needs

RSHEPP 333 days ago |

Just re-wrote an internal CLI to urfave from custom, but having issues with v3 autocomplete scripts. Might just take the time to switch over to cobra and use this.

syvolt 333 days ago | |

I think kong[1] is better than both options although cobra is by far the most popular. Might be worth a look.

Definitely won't look as pretty as the parent project though but I prefer kong in terms of the actual code you need to write.

[1] https://github.com/alecthomas/kong

bbkane 333 days ago | | |

OP said they want completion support, which Kong doesn't include. https://github.com/jotaen/kong-completion exists, but the last commit was 2 years ago.

Cthulhu_ 333 days ago |

That's pretty neat, although it's little more than a coloring wrapper around Cobra. That said, I wrote a small tool for a hackathon and just dropped this in for a bit of whimsy.

Z$ ./example/run --name '' ERROR Flag needs an argument: --name. Try --help for usage.

Z$ ./example/run '' You ran the root command. Now try --help. Z$ ./example/run 'x' ERROR Unknown command "x" for "example". Try --help for usage.

Z$ ./example/run sub "multi-word quoted string" --flag "another quoted string" Ran the sub command! Z$ ./example/run --help A little example program! It doesn’t really do anything, but that’s the point.™ USAGE example [command] [args] [--flags] EXAMPLES # Run it: example # Run it with some arguments: example --name=Carlos -a -s Becker -a # Run a subcommand with an argument: example sub --async --foo=xyz --async arguments # Run with a quoted string: example sub "quoted string" # Mix and match: example sub "multi-word quoted string" --flag "another quoted string" COMMANDS help [command] Help about any command sub [command] [args] [--flags] An example subcommand throw Throws an error FLAGS -a --async Run async -h --help Help for example --name Your name (jane) -s --surname Your surname (doe) -v --version Version for example Z$ ./example/run sub "multi-word quoted string" --flag "another quoted string" zsh: command not found: example sub multi-word quoted string --flag another quoted string