A collection of CLI argument types for the Go `flag` package.

Overview

flagvar

Test

A collection of CLI argument types for the flag package.

import "github.com/sgreben/flagvar"

Or just copy & paste what you need. It's public domain.

Example

package main

import (
	"flag"
	"fmt"
	"github.com/sgreben/flagvar"
)

var (
	fruit    = flagvar.Enum{Choices: []string{"apple", "banana"}}
	urls     flagvar.URLs
	settings flagvar.Assignments
)

func main() {
	flag.Var(&fruit, "fruit", fmt.Sprintf("set a fruit (%s)", fruit.Help()))
	flag.Var(&urls, "url", "add a URL")
	flag.Var(&settings, "set", fmt.Sprintf("specify a setting (%s)", settings.Help()))
	flag.Parse()
}
$ go run main.go -set abc=xyz -url https://github.com
# no error

$ go run main.go -set abc=xyz -url ://github.com
invalid value "://github.com" for flag -url: parse ://github.com: missing protocol scheme

$ go run main.go -fruit kiwi
invalid value "kiwi" for flag -fruit: "kiwi" must be one of [apple banana]

$ go run main.go -h
Usage:
  -fruit value
        set a fruit (one of [apple banana])
  -set value
        specify a setting (a key/value pair KEY=VALUE)
  -url value
        add a URL

Conventions

  • Pluralized argument types (e.g. Strings, Assignments) can be specified repeatedly, the values are collected in a slice.
  • The resulting value is stored in .Value for singular types and in .Values for plural types
  • The original argument string is stored in .Text for singular types and in .Texts for plural types
  • -Set types (EnumSet, StringSet) de-duplicate provided values.
  • -CSV types (IntsCSV, EnumsCSV) accept comma-separated values and accumulate values across flag instances if their .Accumulate field is set to true.
  • Most types implement interface{ Help() string }, which produces a string suitable for inclusion in a help message.

Types

Here's a compact overview:

flagvar type example CLI arg type of resulting Go value
Alternative
Assignment KEY=VALUE struct{Key,Value}
Assignments KEY=VALUE []struct{Key,Value}
AssignmentsMap KEY=VALUE map[string]string
CIDR 127.0.0.1/24 struct{IPNet,IP}
CIDRs 127.0.0.1/24 []struct{IPNet,IP}
CIDRsCSV 127.0.0.1/16,10.1.2.3/8 []struct{IPNet,IP}
Enum apple string
Enums apple []string
EnumsCSV apple,banana []string
EnumSet apple []string
EnumSetCSV apple,banana []string
File ./README.md string
Files ./README.md []string
Floats 1.234 []float64
FloatsCSV 1.234,5.0 []float64
Glob src/**.js glob.Glob
Globs src/**.js []glob.Glob
Ints 1002 []int64
IntsCSV 123,1002 []int64
IP 127.0.0.1 net.IP
IPs 127.0.0.1 []net.IP
IPsCSV 127.0.0.1,10.1.2.3 []net.IP
JSON '{"a":1}' interface{}
JSONs '{"a":1}' []interface{}
Regexp [a-z]+ *regexp.Regexp
Regexps [a-z]+ []*regexp.Regexp
Strings "xyxy" []string
StringSet "xyxy" []string
StringSetCSV y,x,y []string
TCPAddr 127.0.0.1:10 net.TCPAddr
TCPAddrs 127.0.0.1:10 []net.TCPAddr
TCPAddrsCSV 127.0.0.1:10,:123 []net.TCPAddr
Template "{{.Size}}" *template.Template
Templates "{{.Size}}" []*template.Template
TemplateFile "/path/to/template.file" string
Time "10:30 AM" time.Time
Times "10:30 AM" []time.Time
TimeFormat "RFC3339" string
UDPAddr 127.0.0.1:10 net.UDPAddr
UDPAddrs 127.0.0.1:10 []net.UDPAddr
UDPAddrsCSV 127.0.0.1:10,:123 []net.UDPAddr
UnixAddr /example.sock net.UnixAddr
UnixAddrs /example.sock []net.UnixAddr
UnixAddrsCSV /example.sock,/other.sock []net.UnixAddr
URL https://github.com *url.URL
URLs https://github.com []*url.URL
Wrap
WrapCSV
WrapFunc
WrapPointer

Goals / design principles

  • Help avoid dependencies
    • Self-contained > DRY
    • Explicitly support copy & paste workflow
    • Copyable units should be easy to determine
    • Anonymous structs > shared types
  • "Code-you-own" feeling, even when imported as a package
    • No private fields / methods
    • No magic
    • Simple built-in types used wherever possible
    • Avoid introducing new concepts
  • Support "blind" usage
    • Zero values should be useful
    • Avoid introducing failure cases, handle any combination of parameters gracefully.
    • All "obvious things to try" should work.
Releases(v1.10.0)
Owner
Sergey Grebenshchikov
non-stop through desert, salisbury steak sweater
Sergey Grebenshchikov
Golang library with POSIX-compliant command-line UI (CLI) and Hierarchical-configuration. Better substitute for stdlib flag.

cmdr cmdr is a POSIX-compliant, command-line UI (CLI) library in Golang. It is a getopt-like parser of command-line options, be compatible with the ge

hz 109 Jun 28, 2022
The standard library flag package with its missing features

cmd Package cmd is a minimalistic library that enables easy sub commands with the standard flag library. This library extends the standard library fla

Eyal Posener 33 Sep 23, 2021
Drop-in replacement for Go's flag package, implementing POSIX/GNU-style --flags.

Description pflag is a drop-in replacement for Go's flag package, implementing POSIX/GNU-style --flags. pflag is compatible with the GNU extensions to

Steve Francia 1.8k Jun 29, 2022
Struct-based argument parsing in Go

go-arg Struct-based argument parsing for Go Declare command line arguments for your program by defining a struct. var args struct { Foo string Bar b

Alex Flint 1.4k Jun 30, 2022
minigli is a tiny command argument parser for Go.

minigli is a tiny command argument parser for Go.

hitoshi44 0 Jan 29, 2022
command argument completion generator for spf13/cobra

Command argument completion generator for cobra. You can read more about it here: A pragmatic approach to shell completion.

null 39 Jun 9, 2022
Argparse for golang. Just because `flag` sucks

Golang argparse Let's be honest -- Go's standard command line arguments parser flag terribly sucks. It cannot come anywhere close to the Python's argp

Alexey Kamenskiy 433 Jun 25, 2022
Flag is a simple but powerful command line option parsing library for Go support infinite level subcommand

Flag Flag is a simple but powerful commandline flag parsing library for Go. Documentation Documentation can be found at Godoc Supported features bool

null 119 Jun 28, 2022
CONTRIBUTIONS ONLY: A Go (golang) command line and flag parser

CONTRIBUTIONS ONLY What does this mean? I do not have time to fix issues myself. The only way fixes or new features will be added is by people submitt

Alec Thomas 3.2k Jun 28, 2022
Go binding configuration and command flag made easy✨✨

✨ Binding configuration and command flag made easy! ✨ You can use multiple keys tag to simplify the look like this (supported feature**): // single ta

Ii64人 13 Mar 2, 2022
CLI for exploring AWS EC2 Spot inventory. Inspect AWS Spot instance types, saving, price, and interruption frequency.

spotinfo The spotinfo is a command-line tool that helps you determine AWS Spot instance types with the least chance of interruption and provides the s

Alexei Ledenev 64 Jul 1, 2022
CLI tool to convert many common document types to plane text.

Textify. CLI tool to convert many common document types to plane text. Goals. SO many different document types exist today. PDFs, EPUB books, Microsof

Quin 1 Nov 19, 2021
A collection of terminal-based widgets for richer Golang CLI apps.

Flinch A collection of terminal-based widgets for richer Golang CLI apps. Ships with a library to build your own widgets/TUIs too. Warning: This modul

Liam Galvin 34 Jun 28, 2022
A personal collection of handy CLI tools

Toolkit A personal collection of handy CLI tools Installation 1.) Download and extract the ZIP package for the the latest release 2.) Copy the appropr

Luke Johnson 0 Nov 8, 2021
Marshallable - Make generic data types marshallable

Marshallable Make generic data types marshallable! Features Implement methods: S

null 3 Feb 15, 2022
Elegant CLI wrapper for kubeseal CLI

Overview This is a wrapper CLI ofkubeseal CLI, specifically the raw mode. If you just need to encrypt your secret on RAW mode, this CLI will be the ea

Elm 4 Jan 8, 2022
CLI to run a docker image with R. CLI built using cobra library in go.

BlueBeak Installation Guide Task 1: Building the CLI The directory structure looks like Fastest process: 1)cd into bbtools 2)cd into bbtools/bin 3)I h

Aniruddha Chattopadhyay 0 Dec 20, 2021
A wrapper of aliyun-cli subcommand alidns, run aliyun-cli in Declarative mode.

aliyun-dns A wrapper of aliyun-cli subcommand alidns, run aliyun-cli in Declarative mode. Installation Install aliyun-cli. Usage $ aliyun-dns -h A wra

许嘉华 0 Dec 21, 2021
Symfony-cli - The Symfony CLI tool For Golang

Symfony CLI Install To install Symfony CLI, please download the appropriate vers

Symfony CLI 330 Jun 30, 2022