How to handle configuration in Go [closed]

Answer 1

I tried JSON. It worked. But I hate having to create the struct of the exact fields and types I might be setting. To me that was a pain. I noticed it was the method used by all the configuration options I could find. Maybe my background in dynamic languages makes me blind to the benefits of such verboseness. I made a new simple config file format, and a more dynamic-ish lib for reading it out.

https://github.com/chrisftw/ezconf

I am pretty new to the Go world, so it might not be the Go way. But it works, it is pretty quick, and super simple to use.

Pros

• Super simple
• Less code

Cons

• No Arrays or Map types
• Very flat file format
• Non-standard conf files
• Does have a little convention built-in, which I now if frowned upon in general in Go community. (Looks for config file in the config directory)

Answer 2

The JSON format worked for me quite well. The standard library offers methods to write the data structure indented, so it is quite readable.

See also this golang-nuts thread.

The benefits of JSON are that it is fairly simple to parse and human readable/editable while offering semantics for lists and mappings (which can become quite handy), which is not the case with many ini-type config parsers.

Example usage:

conf.json:

{
    "Users": ["UserA","UserB"],
    "Groups": ["GroupA"]
}

Program to read the configuration

import (
    "encoding/json"
    "os"
    "fmt"
)

type Configuration struct {
    Users    []string
    Groups   []string
}

file, _ := os.Open("conf.json")
defer file.Close()
decoder := json.NewDecoder(file)
configuration := Configuration{}
err := decoder.Decode(&configuration)
if err != nil {
  fmt.Println("error:", err)
}
fmt.Println(configuration.Users) // output: [UserA, UserB]

Answer 3

https://github.com/spf13/viper and https://github.com/zpatrick/go-config are a pretty good libraries for configuration files.

Answer 4

Another option is to use TOML, which is an INI-like format created by Tom Preston-Werner. I built a Go parser for it that is extensively tested. You can use it like other options proposed here. For example, if you have this TOML data in something.toml

Age = 198
Cats = [ "Cauchy", "Plato" ]
Pi = 3.14
Perfection = [ 6, 28, 496, 8128 ]
DOB = 1987-07-05T05:45:00Z

Then you can load it into your Go program with something like

type Config struct {
    Age int
    Cats []string
    Pi float64
    Perfection []int
    DOB time.Time
}

var conf Config
if _, err := toml.DecodeFile("something.toml", &conf); err != nil {
    // handle error
}

Answer 5

Viper is a golang configuration management system that works with JSON, YAML, and TOML. It looks pretty interesting.

Answer 6

Just use standard go flags with iniflags.

Standard go flags have the following benefits:

• Idiomatic.
• Easy to use. Flags can be easily added and scattered across arbitrary packages your project uses.
• Flags have out-of-the-box support for default values and description.
• Flags provide standard 'help' output with default values and description.

The only drawback standard go flags have - is management problems when the number of flags used in your app becomes too large.

Iniflags elegantly solves this problem: just modify two lines in your main package and it magically gains support for reading flag values from ini file. Flags from ini files can be overriden by passing new values in command-line.

See also https://groups.google.com/forum/#!topic/golang-nuts/TByzyPgoAQE for details.