confighelper

Generic Configuration Package

This package provides a generic configuration system using the Viper library, allowing users to define their own configuration prefix and provide default configuration.

Usage

Step 1: Create a default YAML configuration file

Create a YAML file that contains the default configuration for your project. For example, let's call it defaults.yaml:

db:
  host: "localhost"
  user: "postgres"
  # password: "" # no default, panic if not set
  name: "cc_terrarium"
  port: 5432
  ssl_mode: false

Step 2: Initialize the configuration

Import the config package and initialize the configuration by providing the prefix and default YAML configuration data:

package main

import (
  "fmt"
  "embed"
  "log"

  "github.com/<username>/<package>/config"
)

//go:embed defaults.yaml
var defaultsYamlFile embed.FS

func main() {
  defaultsYaml, err := defaultsYamlFile.ReadFile("defaults.yaml")
  if err != nil {
    log.Fatal(err)
  }

  defaultsMap := map[string]interface{}{}
  err = yaml.Unmarshal(defaultsYaml, &defaultsMap)
  if err != nil {
    log.Fatal(err)
  }

  cfg, err := config.LoadDefaults(defaultsMap, "TR")
  if err != nil {
    log.Fatal(err)
  }

  // Use the configuration...
  host := viper.GetString("db.host")
  fmt.Println("Host:", host)
}

Step 3: Set configuration values using environment variables

To override the default configuration values, you can set environment variables using the defined prefix and underscore separator. For example, to override the db.host configuration value, you can set the environment variable TR_DB_HOST.

Step 4: Use the configuration values

You can access the configuration values using the Viper library and dot notation. For example, to access the db.host value, use:

host := viper.GetString("db.host")

Refer to the Viper library documentation for more information on accessing configuration values.

Panic if not set

Use the Must... helper functions to panic if the value is not set. This is specially useful to help assert that the required values are set by the user. Example:

host := config.MustGetString("db.host")