confucius

confucius is forked from kkyr/fig project. fig is a tiny library for loading an application's config file and its environment into a Go struct. Individual fields can have default values defined or be marked as required.

I added extra features in project and send a PR. But they were not accepted. That reason I was forked that project.

Why confucius?

• Define your configuration, validations and defaults in a single location
• Optionally load from the environment as well
• Optionally profiles as well
• You can use go:embed file system. You can find example usage in examples/embed folder
• Set environment variable in config file with default value
• Only 4 external dependencies
• Full support fortime.Time & time.Duration
• Tiny API
• Decoders for .yaml, .json and .toml files
• Set String and Reader options for reference config. You can find example usage in examples/reader folder
• Added logger support

Getting Started

$ go get -d github.com/netologist/confucius

Define your config file:

# config.yaml

build: "2020-01-09T12:30:00Z"

server:
    ports:
      - "${SERVER_PORT:8080}"
    cleanup: 1h

logger:
    level: "warn"
    trace: true

Define your struct along with validations or defaults:

package main

import (
  "fmt"

  "github.com/netologist/confucius"
)

type Config struct {
  Build  time.Time `conf:"build" validate:"required"`
  Server struct {
    Host    string        `conf:"host" default:"127.0.0.1"`
    Ports   []int         `conf:"ports" default:"[80,443]"`
    Cleanup time.Duration `conf:"cleanup" default:"30m"`
  }
  Logger struct {
    Level string `conf:"level" default:"info"`
    Trace bool   `conf:"trace"`
  }
}

func main() {
  var cfg Config
  err := confucius.Load(&cfg)
  // handle your err
  
  fmt.Printf("%+v\n", cfg)
  // Output: {Build:2019-12-25 00:00:00 +0000 UTC Server:{Host:127.0.0.1 Ports:[8080] Cleanup:1h0m0s} Logger:{Level:warn Trace:true}}
}

If a field is not set and is marked as required then an error is returned. If a default value is defined instead then that value is used to populate the field.

Fig searches for a file named config.yaml in the directory it is run from. Change the lookup behaviour by passing additional parameters to Load():

confucius.Load(&cfg,
  confucius.File("settings.json"),
  confucius.Dirs(".", "/etc/myapp", "/home/user/myapp"),
) // searches for ./settings.json, /etc/myapp/settings.json, /home/user/myapp/settings.json

Profiles

You can use profiles for other environments.

confucius.Load(&cfg,
  confucius.File("settings.json"),
  confucius.Profiles("test", "integration")
  confucius.ProfileLayout("config-test.yaml") // DEFAULT: config.test.yaml
) // searches settings-test.json, settings-integration.json

String and Reader

You can use string or reader for configuration

confucius.Load(&cfg, 
  confucius.String(`{"application": {"port": 9000}}`, confucius.DecoderJSON),
)

configReader := strings.NewReader(`{"application": {"port": 9000}}`)
confucius.Load(&cfg,
  confucius.Reader(configReader, confucius.DecoderJSON),
)

go:embed support

You can use go:embed file system for config files

//go:embed config
var fs embed.FS

confucius.Load(&cfg,
  confucius.EmbedFS(fs),
)

Logger support

You can integrate with your log library confucius's logs

confucius.Load(&cfg,
  confucius.Logger(
    confucius.SetLevel(confucius.ErrorLevel),
    confucius.SetOutput(os.Stdout),
    confucius.Callback(func(level confucius.LogLevel, message, file string, line int) {
      // log callback for logrus, zap or etc...
    }),
  ),
)

Environment

Need to additionally fill fields from the environment? It's as simple as:

confucius.Load(&cfg, confucius.UseEnv("MYAPP"))

Usage

See usage examples.

Documentation

See go.dev for detailed documentation.

Contributing

PRs are welcome! Please explain your motivation for the change in your PR and ensure your change is properly tested and documented.