config

Abstract

Package log15-config enables configuration of log15 from some arbitrary maps. It does not read any config files, you can use your favourite way of configuring your application. This is a deliberate design decition in order to decouple reading of a configuration from the act of instantiating Handlers and Loggers from this configuration.

Usage

See this example. Detailed examples for all Handlers can be found in the tests. Also please check log15's documentation for the behaviour of the individual handlers.

func getMapFromConfiguration(config string) (map[string]interface{}, error) {
	configMap := make(map[string]interface{})
	err := yaml.Unmarshal([]byte(config), &configMap)
	if err != nil {
		return nil, err
	}
	return configMap, err
}

func Example() {
	var exampleConfiguration = `
  # default for all handlers
  level: INFO
  bufsize: 100  # buffer up to 100 messages before blocking
  extra:
      mark: test
      user: alice

  handlers:
    - kind: stdout  # determines the Handler used
      format: terminal

    - kind: stderr
      format: json
      level: warn	# don't show

    - kind: stdout
      format: logfmt
      level: debug
`

	configMap, err := getMapFromConfiguration(exampleConfiguration)
	if err != nil {
		panic(err)
	}

	log, err := config.Logger(configMap)
	if err != nil {
		panic(err)
	}

	log.Info("Hello, world!")
	log.Debug("user1", "user", "bob")

	l1 := log.New("user", "carol") // issue in log15! won't override, but use both!
	l1.Debug("about user")
}

Look at the Examples for more handler configurations

The kinds for the Handlers are:

• stdout: StreamHandler to os.Stdout

  • format: see Formats below

• stderr: StreamHandler to os.Stderr

  • format: see Formats below

• file: FileHandler to a file

  • format: see Formats below
  • path: path to file

• syslog. SyslogHandler

  • tag: testing
  • facility: local6

also implemented: MatchFilterHandler, MultiHandler, BufferedHandler,FailoverHandler

Format:

one of "terminal","json","logfmt" or a key of a custom format as shown below

Adding a Handler

This is accomplished with the help of mapstructure-hooks. You need:

1. A struct that will hold your config and implements HandlerConfig. Use LevelHandlerConfig for proper level handling.

type AwesomeHandlerConfig struct {
        LevelHandlerConfig `mapstructure:",squash"`
        AwesomeData string // an example for your data
}

Take care that alle fields are exported, otherwise reflection in mapstruct will fail!

1. A function to create an empty config to be filled by mapstruct:

func NewAwesomeHandlerConfig() interface{}{
        return &AwesomeHandlerConfig{}
}

1. Register from init() function

add to config/handler.go's Init():

hooks.Register(HandlerConfigType, "gelf", NewGelfConfig)

Adding a Format

Register the format with AddFormat:

	// add the testingformat to the options
	config.AddFormat("test", func() log15.Format {
		//excludes := []string{"called", "testing", "testrun"}
		excludes := []string{}
		return TerminalTestFormat(excludes)
	})

License

Licensed under Apache 2.0 License