ContainerSSH Logging Library

This library provides internal logging for ContainerSSH. Its functionality is very similar to how syslog does logging.

Note: This is a developer documentation.
The user documentation for ContainerSSH is located at containerssh.github.io.

Getting a logger

The main interface provided by this library is the Logger interface, which is described in logger.go.

You could use it like this:

type MyModule struct {
    logger log.Logger 
}

func (m * MyModule) DoSomething() {
    m.logger.Debug("This is a debug message")
}

The logger provides logging functions for the following levels:

• Debug
• Info
• Notice
• Warning
• Error
• Critical
• Alert
• Emergency

Each of these functions have the following 4 variants:

• Debug logs a string message
• Debuge logs an error
• Debugd logs an arbitrary data structure (interface{})
• Debugf performs a string formating with fmt.Sprintf before logging

In addition, the logger also provides a generic Log(...interface{}) function for compatibility that logs in the info log level.

Creating logger

The simplest way to create a logger is to use the convenience functions:

logger := standard.New()
loggerFactory := standard.NewFactory()

You can also create a custom pipeline if you wish:

writer          := os.Stdout
minimumLogLevel := log.LevelInfo
logFormatter    := ljson.NewLJsonLogFormatter()
p := pipeline.NewLoggerPipeline(minimumLogLevel, logFormatter, writer)
p.Warning("test") 

This will create a pipeline that writes log messages to the standard output in newline-delimited JSON format. You can, of course, also implement your own log formatter by implementing the interface in formatter/formatter.go.

Plugging the go logger in

This package also provides the facility to plug in the go logger. This can be done by creating a logger as follows:

goLogWriter := log.NewGoLogWriter(logger)
goLogger := goLog.New(goLogWriter, "", 0)
goLogger.Println("Hello world!")

If you want to change the log facility globally:

goLogWriter := log.NewGoLogWriter(logger)
log.SetOutput(goLogWriter)
log.Println("Hello world!")