configsrc

Go package for loading configuration information from an external source.

Motivation

TODO

Installation

$ go get github.com/ekyoung/configsrc

Usage

The general pattern is to:

1. Define a struct that represents all the configuration for your app.
2. Write a YAML file for each configuration you want to be able to load.
3. Set environment variables that tell configsrc where it should load a specific configuration file from.
4. Run your app.

configsrc looks for environment variables with a prefix containing a value you specify, plus _CONFIGSRC_. For example, given the prefix "my_app", configsrc looks for environment variables starting with "MY_APP_CONFIGSRC_". The remainder of the environment variable names vary for each supported type of source and are described below.

Sample main.go

package main

import (
	"log"

	"github.com/ekyoung/configsrc"
)

type AppConfig struct {
	MongoConnection string `yaml:"mongo_connection"`
	Mode            string
	Frequency       int
}

func main() {
	cfg := AppConfig{}

	err := configsrc.Load("my_app", &cfg)
	if err != nil {
		log.Fatalf("error: %v\n", err)
		return
	}

	log.Printf("[DEBUG] Config: %v\n", cfg)
}

YAML files are loaded with go-yaml. See the readme in that repo for struct tag options.

Sample config file

mongo_connection: mongodb://localhost/my-db
mode: Active
frequency: 5

S3

configsrc environment variables:

• S3_BUCKET
• S3_KEY

Additionaly, you should set the environment variables expected by the AWS SDK in order to access your S3 resources.

Example

Given a prefix of "my_app", and an AWS Profile named "ACME-Admin" stored in the central credentials file, set the following environment variables:

MY_APP_CONFIGSRC_S3_BUCKET=any-bucket-name
MY_APP_CONFIGSRC_S3_KEY=path/to/config.yaml
AWS_PROFILE=ACME-Admin
AWS_REGION=us-east-1