Logging

Kocha provides a level-based logger.

Basics

Logging feature is provided by Application.Logger.

Usage:

In controller:

func (r *Root) GET(c *kocha.Context) error {
    c.App.Logger.Info("This is a root")
    return c.Render(nil)
}

Configurations

Logger configurations is in config/app.go.

// Logger settings.
Logger: &kocha.LoggerConfig{
    Writer:    os.Stdout,
    Formatter: &log.LTSVFormatter{},
    Level:     log.INFO,
}

The definition of LoggerConfig is following.

// LoggerConfig represents the configuration of the logger.
type LoggerConfig struct {
    Writer    io.Writer     // output destination for the logger.
    Formatter log.Formatter // formatter for log entry.
    Level     log.Level     // log level.
}

Log levels

The log levels are following.

log.NONE (godoc)
log.DEBUG (godoc)
log.INFO (godoc)
log.WARN (godoc)
log.ERROR (godoc)
log.FATAL (godoc)
log.PANIC (godoc)

You can set a log level to Logger by some ways below.

Set log level to LoggerConfig.Level in config/app.go configuration file.
Use log.Logger.SetLevel API

Suppress the output by log level

For example, when log level set to log.INFO.

Logger.Debug("debug log")

It won't be output because log level of Logger.Debug() has a log.DEBUG, and lower than log.INFO.

Logger.Info("info log")
Logger.Error("error log")

It will be output because Logger.Info() and Logger.Error have a log level which equal or upper than log.INFO.

Formatter

Logger has a formatter that format to specific log format.

Built-in formatter

Kocha provides formatter below.

LTSVFormatter (godoc)

A formatter of Labeled Tab-separated Values (LTSV).
This is the default formatter of Kocha if you haven't specified the formatter.
See http://ltsv.org/ for more details of LTSV.

level:INFO  time:2014-07-30T17:45:40.419347835+09:00    method:GET  protocol:HTTP/1.1   status:200  uri:/
level:INFO  time:2014-07-30T17:45:48.238892704+09:00    method:GET  protocol:HTTP/1.1   status:404  uri:/user

Custom formatter

You can define your own custom formatter.

Implements the log.Format interface.
It set to AppConfig.Logger.Formatter in config/app.go.