Config

A go package for creating default configuration variables that can be overridden by environment variables.

Install

go get github.com/bjubes/config

Usage

1. Create a struct with fields that match your environment variables, and create an instance set to your defaults.

   type MyConfig struct {
   	DB_HOST  string
   	DB_PORT  int
   	PROD     bool
   	COOLDOWN float64
   }
   var myConfig config.Configurator = MyConfig{
   	DB_HOST:  "localhost",
   	DB_PORT:  5432,
   	PROD:     false,
   	COOLDOWN: 0.3,
   }

2. Make your custom struct implements the Configurator interface using the following code (just copy and paste)

   func (c MyConfig) GetEnvString(field string) string {
   	return config.GetEnvString(c, field)
   }
   func (c MyConfig) GetEnvBool(field string) bool {
   	return config.GetEnvBool(c, field)
   }
   func (c MyConfig) GetEnvInt(field string) int {
   	return config.GetEnvInt(c, field)
   }
   func (c MyConfig) GetEnvFloat(field string) float64 {
   	return config.GetEnvFloat(c, field)
   }

3. Retrieve a value using the methods on your config instance

   host := myConfig.GetEnvString("DB_HOST")
   port := myConfig.GetEnvInt("DB_PORT")
   prod := myConfig.GetEnvBool("PROD")
   cool := myConfig.GetEnvFloat("COOLDOWN")

Values will default to what they are set to in the struct instance, but will be overridden by environment variables if they are set. Environment variables must match the type specified. For specifics, see type matching rules below.

Since the myConfig instance has a type of Configurator, none of the public fields are accesssable. This forces retreiving values through the GetEnv methods, so you never accidentally grab the default value without checking for the environment variable first.

Type matching rules

If the environment variable doesn't meet these rules the default value will be used instead.

string - Environment value will be used as long as it is set, even if its an empty string.

bool - Environment value will be used if the value is a bool, as determined by strconv.ParseBool. Accepted values are: 1, t, T, TRUE, true, True, 0, f, F, FALSE, false, False.

int - Environment value will be used if the value is an integer, as determined by strconv.Atoi.

float - Environment value will be used if the value is a float, as determined by strconv.ParseFloat.