Logger

class Logger

• Logger
• Reference
• Object

Overview

The Logger class provides a simple but sophisticated logging utility that you can use to output messages-

The messages have associated levels, such as INFO or ERROR that indicate their importance. You can then give the Logger a level, and only messages at that level of higher will be printed-

For instance, in a production system, you may have your Logger set to INFO or even WARN. When you are developing the system, however, you probably want to know about the program’s internal state, and would set the Logger to DEBUG.

If logging to multiple locations is required, an IO::MultiWriter can be used.

Example

require "logger"

log = Logger.new(STDOUT)
log.level = Logger::WARN

log.debug("Created logger")
log.info("Program started")
log.warn("Nothing to do!")

begin
  File.each_line("/foo/bar.log") do |line|
    unless line =~ /^(\w+) = (.*)$/
      log.error("Line in wrong format: #{line}")
    end
  end
rescue err
  log.fatal("Caught exception; exiting")
  log.fatal(err)
end

Defined in:

Constant Summary

DEBUG = Severity::DEBUG

ERROR = Severity::ERROR

FATAL = Severity::FATAL

INFO = Severity::INFO

UNKNOWN = Severity::UNKNOWN

WARN = Severity::WARN

Class Method Summary

• .new(io : IO?)

  Creates a new logger that will log to the given io.

Instance Method Summary

• #close

  Calls the close method on the object passed to initialize.

• #debug(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to DEBUG.

• #debug(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to DEBUG.

• #debug?

  Returns true if the logger's current severity is lower or equal to DEBUG.

• #error(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to ERROR.

• #error(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to ERROR.

• #error?

  Returns true if the logger's current severity is lower or equal to ERROR.

• #fatal(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to FATAL.

• #fatal(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to FATAL.

• #fatal?

  Returns true if the logger's current severity is lower or equal to FATAL.

• #formatter : String, Time, String, String, IO -> Nil
• #formatter=(formatter)
• #info(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to INFO.

• #info(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to INFO.

• #info?

  Returns true if the logger's current severity is lower or equal to INFO.

• #level : Severity
• #level=(level : Severity)
• #log(severity, message, progname = nil)

  Logs message if severity is higher or equal with the logger's current severity.

• #log(severity, progname = nil, &block)

  Logs the message as returned from the given block if severity is higher or equal with the loggers current severity.

• #progname : String
• #progname=(progname : String)
• #unknown(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to UNKNOWN.

• #unknown(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to UNKNOWN.

• #unknown?

  Returns true if the logger's current severity is lower or equal to UNKNOWN.

• #warn(progname = nil, &block)

  Logs the message as returned from the given block if the logger's current severity is lower or equal to WARN.

• #warn(message, progname = nil)

  Logs message if the logger's current severity is lower or equal to WARN.

• #warn?

  Returns true if the logger's current severity is lower or equal to WARN.

Class Method Detail

Instance Method Detail