Yet another Config Parser for go
This is a config parser most similar to Nginx, supports Json format, but with line-breaks, comments, etc. Also, like Nginx is more lenient.
Uses same syntax as https://github.com/vstakhov/libucl
Use SublimeText Nginx Plugin for formatting.
Credit to BurntSushi/Toml and Apcera/Gnatsd from which this was derived.
Other Options
There are a variety of options for config with comments in Go, this project started before some of them which are now probably better options:
- https://github.com/hjson/hjson-go
- Similar to above? https://github.com/tailscale/hujson
- https://github.com/lalamove/konfig
- https://github.com/hashicorp/hcl
Example
# nice, a config with comments!
# support the name = value format
title = "conf Example"
# support json semicolon
title2 : "conf example2"
# support omitting = or : because key starts a line
title3 "conf example"
# note, we do not have to have quotes
title4 = Without Quotes
# for Sections we can use brackets
hand {
name = "Tyrion"
organization = "Lannisters"
bio = "Imp" // comments on fields
dob = 1979-05-27T07:32:00Z # dates, and more comments on fields
}
// Note, double-slash comment
// section name/value that is quoted and json valid, including commas
address : {
"street" : "1 Sky Cell",
"city" : "Eyre",
"region" : "Vale of Arryn",
"country" : "Westeros"
}
# sections can omit the colon, equal before bracket
seenwith {
# nested section
# can be spaces or tabs for nesting
jaime : {
season = season1
episode = "episode1"
}
cersei = {
season = season1
episode = "episode1"
}
}
# Line breaks are OK when inside arrays
seasons = [
"season1",
"season2",
"season3",
"season4",
"???"
]
# long strings can use parens to allow multi-line
description (
we possibly
can have
multi line text with a block paren
block ends with end paren on new line
)
And the corresponding Go types are:
type Config struct {
Title string
Hand HandOfKing
Location *Address `confl:"address"`
Seenwith map[string]Character
Seasons []string
Description string
}
type HandOfKing struct {
Name string
Org string `json:"organization"` // Reads either confl, or json attributes
Bio string
DOB time.Time
Deceased bool
}
type Address struct {
Street string
City string
Region string
ZipCode int
}
type Character struct {
Episode string
Season string
}Note that a case insensitive match will be tried if an exact match can't be found.
A working example of the above can be found in _examples/example.{go,conf}.
Examples
This package works similarly to how the Go standard library handles XML
and JSON. Namely, data is loaded into Go values via reflection.
For the simplest example, consider a file as just a list of keys and values:
// Comments in Config
Age = 25
# another comment
Cats = [ "Cauchy", "Plato" ]
# now, using quotes on key
"Pi" = 3.14
Perfection = [ 6, 28, 496, 8128 ]
DOB = 1987-07-05T05:45:00Z
Which could be defined in Go as:
type Config struct {
Age int
Cats []string
Pi float64
Perfection []int
DOB time.Time
}And then decoded with:
var conf Config
if err := confl.Unmarshal(byteData, &conf); err != nil {
// handle error
}You can also use struct tags if your struct field name doesn't map to a confl key value directly:
some_key_NAME = "wat"
type Config struct {
ObscureKey string `confl:"some_key_NAME"`
}Using the encoding.TextUnmarshaler interface
Here's an example that automatically parses duration strings into
time.Duration values:
song [
{
name = "Thunder Road"
duration = "4m49s"
},
{
name = "Stairway to Heaven"
duration = "8m03s"
}
]
Which can be decoded with:
type song struct {
Name string
Duration duration
}
type songs struct {
Song []song
}
var favorites songs
if err := confl.Unmarshal(blob, &favorites); err != nil {
log.Fatal(err)
}
for _, s := range favorites.Song {
fmt.Printf("%s (%s)\n", s.Name, s.Duration)
}And you'll also need a duration type that satisfies the
encoding.TextUnmarshaler interface:
type duration struct {
time.Duration
}
func (d *duration) UnmarshalText(text []byte) error {
var err error
d.Duration, err = time.ParseDuration(string(text))
return err
}