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rconfig/README.md
Knut Ahlers 4c83f34ecf
README: Fix test instruction
Signed-off-by: Knut Ahlers <knut@ahlers.me>
2021-09-06 19:06:13 +02:00

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[![Go Report Card](https://goreportcard.com/badge/github.com/Luzifer/rconfig)](https://goreportcard.com/report/github.com/Luzifer/rconfig)
[![Documentation](https://badges.fyi/static/godoc/reference/5272B4)](https://pkg.go.dev/github.com/Luzifer/rconfig/v2)
![](https://badges.fyi/github/license/Luzifer/rconfig)
![](https://badges.fyi/github/latest-tag/Luzifer/rconfig)
## Description
> Package rconfig implements a CLI configuration reader with struct-embedded defaults, environment variables and posix compatible flag parsing using the [pflag](https://github.com/spf13/pflag) library.
## Installation
Install by running:
```
go get -u github.com/Luzifer/rconfig/v2
```
Run tests by running in the checkout folder:
```
go test -v -race -cover ./...
```
## Usage
A very simple usecase is to just configure a struct inside the vars section of your `main.go` and to parse the commandline flags from the `main()` function:
```go
package main
import (
"fmt"
"github.com/Luzifer/rconfig/v2"
)
var (
cfg = struct {
Username string `default:"unknown" flag:"user" description:"Your name"`
Details struct {
Age int `default:"25" flag:"age" env:"age" description:"Your age"`
}
}{}
)
func main() {
rconfig.Parse(&cfg)
fmt.Printf("Hello %s, happy birthday for your %dth birthday.",
cfg.Username,
cfg.Details.Age)
}
```
### Provide variable defaults by using a file
Given you have a file `~/.myapp.yml` containing some secrets or usernames (for the example below username is assumed to be "luzifer") as a default configuration for your application you can use this source code to load the defaults from that file using the `vardefault` tag in your configuration struct.
The order of the directives (lower number = higher precedence):
1. Flags provided in command line
1. Environment variables
1. Variable defaults (`vardefault` tag in the struct)
1. `default` tag in the struct
```go
var cfg = struct {
Username string `vardefault:"username" flag:"username" description:"Your username"`
}
func main() {
rconfig.SetVariableDefaults(rconfig.VarDefaultsFromYAMLFile("~/.myapp.yml"))
rconfig.Parse(&cfg)
fmt.Printf("Username = %s", cfg.Username)
// Output: Username = luzifer
}
```
## More info
You can see the full reference documentation of the rconfig package [at pkg.go.dev](https://pkg.go.dev/github.com/Luzifer/rconfig/v2)