define flagset with struct and reflect
- Builds pflag.FlagSet by struct definition
- Supports only a single use case (shorthand of flag package)
- Nested structure support (example, shared common option)
- Default envvar support
$ go get -v github.com/podhmo/flagstructpackage main
import (
"fmt"
"os"
"github.com/podhmo/flagstruct"
)
type Options struct {
Name string `flag:"name" help:"name of greeting"`
Verbose bool `flag:"verbose" short:"v"`
}
func main() {
options := &Options{Name: "foo"} // default value
flagstruct.Parse(options, func(b *flagstruct.Builder) {
b.Name = "hello"
b.EnvPrefix = "X_"
})
fmt.Printf("parsed: %#+v\n", options)
}default help message.
$ hello --help
Usage of hello:
--name string ENV: X_NAME name of greeting (default "foo")
-v, --verbose ENV: X_VERBOSE -
pflag: help requested
exit status 2run it.
$ hello --verbose
parsed: &main.Options{Name:"foo", Verbose:true}
$ hello -v --name bar
parsed: &main.Options{Name:"name", Verbose:true}
# envvar support
$ X_NAME=bar hello -v
parsed: &main.Options{Name:"bar", Verbose:true}see also ./examples