Introduction

config is a simple golang library and designed to read configurations from JSON, Yaml files, environment variables and command line. config depends on go-yaml to anlayze Yaml file and uses built-in golang library to handle JSON file.

Installation

1. Install Yaml library first:

go get gopkg.in/yaml.v2

2. Install config library:

go get github.com/eschao/config

Usage

I. Data types

Like JSON, Yaml, config uses tags to define configurations. It supports the following golang data types:

• bool
• string
• int8, int16, int, int32, int64
• uint8, uint16, uint, uint32, uint64
• float32, float64
• slice type. e.g: []string, []int ...

II. Defines default values

Using default keyword in structure tags to define default value. Example codes:

  type Log struct {
    Path  string `default:"/var/logs"`
    Level string `default:"debug"`
  }

After that, calls config.ParseDefault(interface{}) to set structure instance with default values. Example codes:

  logConfig := Log{}
  config.ParseDefault(&logConfig)

III. Reads configurations from JSON and Yaml files

1. Using json to define configuration name

  type Database struct {
    Host string     `json:"host"`
    Port int        `json:"port"`
    Username string `json:"username" default:"admin"`
    Password string `json:"password" default:"admin"`
    Log Log         `json:"log"`
  }

2. Using yaml to define configuration name

  type Database struct {
    Host string     `yaml:"host"`
    Port int        `yaml:"port"`
    Username string `yaml:"username" default:"admin"`
    Password string `yaml:"password" default:"admin"`
    Log Log         `yaml:"log"`
  }

Parsing configurations from JSON:

  dbConfig := Database{}
  config.ParseConfigFile(&dbConfig, "config.json")