cfg

Convenient configuration builder. Inject data straight to your configuration struct from various input source (env, flags, files, you name it!)

Example

The simplest way to use upfluence/cfg is:

package main

import (
  "context"
  "fmt"
  "os"

  "github.com/upfluence/cfg"
)

type config struct {
  Arg1 string `env:"ARG_1" flag:"arg1"`
  Arg2 string `env:"ARG_2" flag:"arg2"`
}

func main() {
  var (
    c config

    ctx = context.Background()
  )

  if err := cfg.NewDefaultConfigurator().Populate(ctx, &c); err != nil {
    fmt.Fprintf(os.Stderr, "cannot populate config: %s\n", err.Error())
    os.Exit(1)
  }

  fmt.Printf("Arg1: %s, Arg2: %s\n", c.Arg1, c.Arg2)
}

By default only the env and flags providers are used.

You can now provide configuration to your application through:

• env:

$ ARG_1=foo ARG_2 ./example
Arg1: foo, Arg2: bar

• flags:

$ ./example --arg1 foo --arg2 bar
Arg1: foo, Arg2: bar

• flags:booleans:

$ ./example --arg1 --no-arg2
Arg1: TRUE, Arg2: FALSE

Provider

Implemented providers:

Environment

TODO

Flags

TODO

JSON input

TODO

Static

TODO

Create your own

TODO

Roadmap

So far the implementation is pretty minimal. There is two main kinds of improvement.

Field parsing

The current implementation parses:

• string
• all int and float types
• bool
• time.Duration using time.ParseDuration
• time.Time based on the format 2006-01-02T15:04:05
• sub structs
• slices
• maps
• All the value or pointer to a value that implements:
  • json.Unmarshaler
  • encoding.TextUnmarshaler
  • interface { Parse(string) error }

Other provider

A few more provider are on the roadmap.

• More file types. We could include YAML and TOML file parsing provider