aconf

aconf

HOCON format reading/parsing library written in golang

Motivation

Storing configuration information in human friendly format is a requirement common across projects of all sizes.
The HOCON format, made popular by the Akka project, provides a specification which describes a configuration file format for precisely this purpose.
There are many popular config file formats/API's in the world of golang - most popular being TOML, YAML, INI, etc. While these formats are popular, I believe none provide the flexibility provided by the HOCON format.
The aconf library has been designed with the aim of attempting to allow Golang developers make full use of the HOCON configuration format using an extremely simple API.

Getting the library

go get -u github.com/en-vee/aconf

Features

• Similar to the encoding/json library, one can Unmarshal/Decode a HOCON file into a go struct
• Specify config properties as Units such as duration and size.
• Specify config properties as Arrays of primitives or arrays of objects

API Usage

• Define the HOCON Configuration file. All property keys will need to start with a capital letter

A {
    B = 10
    T = 25 seconds
    C = [1, 2, 3, 4]
}

• Create a HOCON parser by providing an io.Reader to read the file

reader, err := os.Open("/path/to/configFilename.conf")
parser := &aconf.HoconParser{}

• Declare a go struct to match the configuration file format. Note that all the members of the go struct need to be exported/capitalized and the field names within the struct should exactly match the field names in the HOCON config file.
• Struct Tags are also supported with the key being hocon. An example is shown below. The tag key must be hocon

type ConfigFile struct {
    A struct {
        B int `hocon:"b"`
        T time.Duration
        C []int
    }
}

• Call the Parse method to decode the Configuration file contents into the pointer to the struct

var appConfig = &ConfigFile{}
if err := parser.Parse(reader, appConfig); err != nil {
			fmt.Printf("Error %v", err)
}

• If the Parse method returns without errors, the appConfig pointer in the example above will be populated with the values from the config file. For example, appConfig.B = 10 or appConfig.T = 25s
• Be sure to have a look at the parser_test.go file for various examples of Config file formats