configparser

Parse a json or yaml file and unmarshal the content to a struct type

To set the values of the struct members from environment variables, you can define an "env" struct tag which defines the name of the envvar to set the value from and call configparser.SetValuesFromEnvironmentTag on the already parsed struct or use configparser.SetValuesFromEnvironment to lookup the envvar by the name of the fields.

Example

This is the config yaml

name: sebidude
age: 99
species: unknown
street: see address
address:
street: homestreet
city: donk city
limit: 10

Define a stuct type

type Address struct {
Street string `json:"street" env:"USER_ADDRESS_STREET"`
City string `json:"city"`
}
type User struct {
Name string `json:"name" env:"USER_NAME"`
Age int `json:"age" env:"USER_AGE"`
Species string `json:"species" env:"USER_SPECIES"`
Street string `json:"street" env:"USER_STREET"`
NoEnv string `json:"noenv"`
Address Address `json:"address"`
Limit int `json:"limit"`
}

Parse the configfile

...
var user User
configparser.ParseYaml("config.yaml",&user)
...

Use environment variables

Set values from env var using struct tags

configparser.SetValuesFromEnvironmentTag(&user)

The env vars stated in the tags will be looked up and set if not empty

To set the values from env vars without defining a struct tag, use a matching name for the variable and set the values with configparser.SetValuesFromEnvironment("CONFIG",&user)

Example

export CONFIG_ADDRESS_CITY="Londinium"

configparser.SetValuesFromEnvironment("CONFIG",&user)
fmt.Println(user.Address.City)