TOML parser and encoder library for Golang

Notice

This is an modification version of toml parser to be used in configo, Use the original project if you do not need configo.

TOML parser and encoder library for Golang.

This library is compatible with TOML version v0.4.0.

Installation

go get -u github.com/naoina/toml

Usage

The following TOML save as example.toml.

# This is a TOML document. Boom.

title = "TOML Example"

[owner]
name = "Lance Uppercut"
dob = 1979-05-27T07:32:00-08:00 # First class dates? Why not?

[database]
server = "192.168.1.1"
ports = [ 8001, 8001, 8002 ]
connection_max = 5000
enabled = true

[servers]

  # You can indent as you please. Tabs or spaces. TOML don't care.
  [servers.alpha]
  ip = "10.0.0.1"
  dc = "eqdc10"

  [servers.beta]
  ip = "10.0.0.2"
  dc = "eqdc10"

[clients]
data = [ ["gamma", "delta"], [1, 2] ]

# Line breaks are OK when inside arrays
hosts = [
  "alpha",
  "omega"
]

Then above TOML will mapping to tomlConfig struct using toml.Unmarshal.

package main

import (
    "io/ioutil"
    "os"
    "time"

    "github.com/naoina/toml"
)

type tomlConfig struct {
    Title string
    Owner struct {
        Name string
        Dob  time.Time
    }
    Database struct {
        Server        string
        Ports         []int
        ConnectionMax uint
        Enabled       bool
    }
    Servers map[string]Server
    Clients struct {
        Data  [][]interface{}
        Hosts []string
    }
}

type Server struct {
    IP string
    DC string
}

func main() {
    f, err := os.Open("example.toml")
    if err != nil {
        panic(err)
    }
    defer f.Close()
    buf, err := ioutil.ReadAll(f)
    if err != nil {
        panic(err)
    }
    var config tomlConfig
    if err := toml.Unmarshal(buf, &config); err != nil {
        panic(err)
    }
    // then to use the unmarshaled config...
}

Mappings

A key and value of TOML will map to the corresponding field. The fields of struct for mapping must be exported.

The rules of the mapping of key are following:

Exact matching

timeout_seconds = 256

type Config struct {
	Timeout_seconds int
}

Camelcase matching

server_name = "srv1"

type Config struct {
	ServerName string
}

Uppercase matching

ip = "10.0.0.1"

type Config struct {
	IP string
}

See the following examples for the value mappings.

String

val = "string"

type Config struct {
	Val string
}

Integer

val = 100

type Config struct {
	Val int
}

All types that can be used are following:

• int8 (from -128 to 127)
• int16 (from -32768 to 32767)
• int32 (from -2147483648 to 2147483647)
• int64 (from -9223372036854775808 to 9223372036854775807)
• int (same as int32 on 32bit environment, or int64 on 64bit environment)
• uint8 (from 0 to 255)
• uint16 (from 0 to 65535)
• uint32 (from 0 to 4294967295)
• uint64 (from 0 to 18446744073709551615)
• uint (same as uint on 32bit environment, or uint64 on 64bit environment)

Float

val = 3.1415

type Config struct {
	Val float32
}

All types that can be used are following:

• float32
• float64

Boolean

val = true

type Config struct {
	Val bool
}

Datetime

val = 2014-09-28T21:27:39Z

type Config struct {
	Val time.Time
}

Array

val = ["a", "b", "c"]

type Config struct {
	Val []string
}

Also following examples all can be mapped:

val1 = [1, 2, 3]
val2 = [["a", "b"], ["c", "d"]]
val3 = [[1, 2, 3], ["a", "b", "c"]]
val4 = [[1, 2, 3], [["a", "b"], [true, false]]]

type Config struct {
	Val1 []int
	Val2 [][]string
	Val3 [][]interface{}
	Val4 [][]interface{}
}

Table

[server]
type = "app"

  [server.development]
  ip = "10.0.0.1"

  [server.production]
  ip = "10.0.0.2"

type Config struct {
	Server map[string]Server
}

type Server struct {
	IP string
}

You can also use the following struct instead of map of struct.

type Config struct {
	Server struct {
		Development Server
		Production Server
	}
}

type Server struct {
	IP string
}

Array of Tables

[[fruit]]
  name = "apple"

  [fruit.physical]
    color = "red"
    shape = "round"

  [[fruit.variety]]
    name = "red delicious"

  [[fruit.variety]]
    name = "granny smith"

[[fruit]]
  name = "banana"

  [[fruit.variety]]
    name = "plantain"

type Config struct {
	Fruit []struct {
		Name string
		Physical struct {
			Color string
			Shape string
		}
		Variety []struct {
			Name string
		}
	}
}

Using toml.UnmarshalTOML interface

duration = "10s"

import time

type Config struct {
	Duration Duration
}

type Duration struct {
	time.Duration
}

func (d *Duration) UnmarshalTOML(data []byte) error {
	d.Duration, err := time.ParseDuration(string(data))
	return err
}

API documentation

See Godoc.

License

MIT