configflag

Documentation

Overview

Package configflag provides a utility for registering config related command line options with the stdlib flag package.

Index

• type FlagStringSlice
  • func (i *FlagStringSlice) Set(value string) error
  • func (i *FlagStringSlice) String() string
• type Options
  • func (opts *Options) MainLoad(target interface{}, loadOpts config.Options) error
  • func (opts *Options) Register()
  • func (opts *Options) RegisterFlagSet(cmd *flag.FlagSet)

Examples

• FlagStringSlice

Types

type FlagStringSlice

type FlagStringSlice struct {
	Value []string
	// contains filtered or unexported fields
}

FlagStringSlice represents a slice of strings. When used as a flag variable, it allows for multiple string values. For example, it can be used like this:

var configFiles FlagStringSlice
flag.Var(&configFiles, "f", "configuration file(s)")

Then it can be invoked like this:

./app -f file1.yaml -f file2.yaml -f valueN.yaml

Finally, when the flags are parsed, the variable contains all the values.

Example

The FlagStringSlice allows for multiple values when used as a flag variable.

package main

import (
	"flag"
	"fmt"

	"github.com/m3db/m3/src/x/config/configflag"
)

func main() {
	var configFiles configflag.FlagStringSlice
	fs := flag.NewFlagSet("config", flag.PanicOnError)
	fs.Var(&configFiles, "f", "config files")
	noError(fs.Parse([]string{"-f", "file1.yaml", "-f", "file2.yaml", "-f", "file3.yaml"}))

	fmt.Println("Config files:", configFiles.Value)
}

func noError(err error) {
	if err != nil {
		panic(err.Error())
	}
}

Output:

Config files: [file1.yaml file2.yaml file3.yaml]

func (*FlagStringSlice) Set

func (i *FlagStringSlice) Set(value string) error

Set appends a string value to the slice.

func (*FlagStringSlice) String

func (i *FlagStringSlice) String() string

String() returns a string implementation of the slice.

type Options

type Options struct {
	// set by commandline flags
	// ConfigFiles (-f) is a list of config files to load
	ConfigFiles FlagStringSlice

	// ShouldDumpConfigAndExit (-d) causes MainLoad to print config to stdout,
	// and then exit.
	ShouldDumpConfigAndExit bool
	// contains filtered or unexported fields
}

Options represents the values of config command line flags

func (*Options) MainLoad

func (opts *Options) MainLoad(target interface{}, loadOpts config.Options) error

MainLoad is a convenience method, intended for use in main(), which handles all config commandline options. It:

• Dumps config and exits if -d was passed.
• Loads configuration otherwise.

Users who want a subset of this behavior should call individual methods.

func (*Options) Register

func (opts *Options) Register()

Register registers commandline options with the default flagset.

func (*Options) RegisterFlagSet

func (opts *Options) RegisterFlagSet(cmd *flag.FlagSet)

RegisterFlagSet registers commandline options with the given flagset.