gonfigs

Assign environment, argument and/or default values to struct variables using Golang tags.

Description

Gonfigs parses a *struct for "gonfigs" tags like argName, envName, default and using them to set the value of the corresponding fields.

If more than one gonfigs tag are matching for a field, the priority for setting the value is:

argName > envName > default

Tags:

• argName looks for a flag.Flag (command line argument) with the name corresponding to the tag value. Will be listed, when using '--help'
• envName looks for an environment variable with the name corresponding to the tag value
• default will use the tags value for the field
• description the description of the field. For documentation and/or if argName is although set, it will be shown in the usage field when using --help in the command line.

Struct fields will be set only, if their current values are zero (Value.IsZero()==true).

At the moment, the following struct fields types are supported: unit, *uint, string and *string

Gonfigs will panic, if the config is not a struct, config is not a pointer and the tags are used on unsupported field types.

Example

import (
  "github.com/Someone0nEarth/gonfigs"
)

...

type DatabaseConfig struct {
	User         *string `envName:"DB_USER"          argName:"db_user"                         
	Password     string  `envName:"DB_USER_PASSWORD" argName:"db_user_password"`
	Host         *string `envName:"DB_HOST"          argName:"db_host"           default:"localhost"`
	Port         *uint   `envName:"DB_PORT"          argName:"db_port"           default:"3306"`
	RootPassword string  `envName:"DB_ROOT_PASSWORD" argName:"db_root_password"                       description:"Will be used for creating the database if necessary."`
	DatabaseName *string `envName:"DB_NAME"          argName:"db_name"           default:"fancy_app"  description:"Database with this name will be created if not already existing."`
}

...

dbConfig := DatabaseConfig{}

gonfigs.Parse(&dbConfig)

...

Similar Projects

If gonfigs is not fitting your needs, maybe one of the following projects will do it:

• https://github.com/caarlos0/env
• https://github.com/tkanos/gonfig (I "created" the name gonfigs before I knew about gonfig ;-)
• https://github.com/spf13/viper

Feedback

Feel free to suggests, fork, contribute, request, improve, criticize and so on :)

Have fun,

someone.earth