go-envcfg – src.euxane.eu

Branches: master 2015-02-14

envcfg

Package envcfg provides environment variable mapping to structs.

It can be used to read configuration parameters from the environment.

Fields for which environment variables can be found are overwritten, otherwise they are left to their previous value.

This package can be used, for example, after gcfg to override settings provided in a configuration file.

import "github.com/Pacien/envcfg"

Documentation

Package documentation can be found on GoDoc

Usage example

Set environment variables:

export PORT=8080
export USER_PASSWORD="S3cUrE"

Create a struct optionally with tagged fields and/or already set values, then call the ReadInto function to read the values set in the environment variables.

package main

import (
    "fmt"
    "github.com/Pacien/envcfg"
)

type Config struct {
    Server struct {
        Port        int `env:"PORT" absenv:"true"`
    }
    User struct {
        Username    string
        Password    string
    }
}

var cnf Config

func (c *Config) setDefaults() *Config {
    c.User.Username = "root"
    c.User.Password = "password"
    return c
}

func init() {
    cnf.setDefaults()

    _, errs := envcfg.ReadInto(&cnf)
    if len(errs) != 0 {
        fmt.Println(errs)
    }
}

func main() {
    fmt.Println(cnf)
}

Output of the previous program:

{{8080} {root S3cUrE}}

See tests for other examples.

License

This program is published under the MIT License. See the LICENSE.txt file.

Other documents

LICENSE.txt

The MIT License (MIT)

Copyright (c) 2015 Pacien TRAN-GIRARD

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.