class Lumberjack::Logger
Logger is a thread safe logging object. It has a compatible API with the Ruby standard library Logger class, the Log4r gem, and ActiveSupport::BufferedLogger.
Example¶ ↑
logger = Lumberjack::Logger.new logger.info("Starting processing") logger.debug("Processing options #{options.inspect}") logger.fatal("OMG the application is on fire!")
Log entries are written to a logging Device if their severity meets or exceeds the log level.
Devices may use buffers internally and the log entries are not guaranteed
to be written until you call the flush
method. Sometimes this
can result in problems when trying to track down extraordinarily long
running sections of code since it is likely that none of the messages
logged before the long running code will appear in the log until the entire
process finishes. You can set the :flush_seconds
option on the
constructor to force the device to be flushed periodically. This will
create a new monitoring thread, but its use is highly recommended.
Each log entry records the log message and severity along with the time it was logged, the program name, process id, and unit of work id. The message will be converted to a string, but otherwise, it is up to the device how these values are recorded. Messages are converted to strings using a Formatter associated with the logger.
Attributes
The device being written to.
The time that the device was last flushed.
The name of the program associated with log messages.
Set silencer
to false to disable silencing the log.
Public Class Methods
Create a new logger to log to a Device.
The device
argument can be in any one of several formats.
If it is a Device object, that object will be
used. If it has a write
method, it will be wrapped in a Device::Writer class. If it is
:null
, it will be a Null device that won't record any
output. Otherwise, it will be assumed to be file path and wrapped in a Device::LogFile class.
This method can take the following options:
-
:level
- The logging level below which messages will be ignored. -
:progname
- The name of the program that will be recorded with each log entry. -
:flush_seconds
- The maximum number of seconds between flush calls. -
:roll
- If the log device is a file path, it will be a Device::DateRollingLogFile if this is set. -
:max_size
- If the log device is a file path, it will be a Device::SizeRollingLogFile if this is set.
All other options are passed to the device constuctor.
# File lib/lumberjack/logger.rb, line 58 def initialize(device = STDOUT, options = {}) @thread_settings = {} options = options.dup self.level = options.delete(:level) || INFO self.progname = options.delete(:progname) max_flush_seconds = options.delete(:flush_seconds).to_f @device = open_device(device, options) @_formatter = Formatter.new @lock = Mutex.new @last_flushed_at = Time.now @silencer = true create_flusher_thread(max_flush_seconds) if max_flush_seconds > 0 end
Public Instance Methods
Add a message to the log with a given severity. The message can be either
passed in the message
argument or supplied with a block. This
method is not normally called. Instead call one of the helper functions
fatal
, error
, warn
,
info
, or debug
.
The severity can be passed in either as one of the Severity constants, or as a Severity label.
Example¶ ↑
logger.add(Lumberjack::Severity::ERROR, exception) logger.add(Lumberjack::Severity::INFO, "Request completed") logger.add(:warn, "Request took a long time") logger.add(Lumberjack::Severity::DEBUG){"Start processing with options #{options.inspect}"}
# File lib/lumberjack/logger.rb, line 100 def add(severity, message = nil, progname = nil) severity = Severity.label_to_level(severity) if severity.is_a?(String) || severity.is_a?(Symbol) return unless severity && severity >= level time = Time.now if message.nil? if block_given? message = yield else message = progname progname = nil end end message = @_formatter.format(message) progname ||= self.progname entry = LogEntry.new(time, severity, message, progname, $$, Lumberjack.unit_of_work_id) begin device.write(entry) rescue => e $stderr.puts("#{e.class.name}: #{e.message}#{' at ' + e.backtrace.first if e.backtrace}") $stderr.puts(entry.to_s) end nil end
Close the logging device.
# File lib/lumberjack/logger.rb, line 138 def close flush @device.close if @device.respond_to?(:close) end
Log a DEBUG
message. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 184 def debug(message = nil, progname = nil, &block) add(DEBUG, message, progname, &block) end
Return true
if DEBUG
messages are being logged.
# File lib/lumberjack/logger.rb, line 189 def debug? level <= DEBUG end
Log an ERROR
message. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 154 def error(message = nil, progname = nil, &block) add(ERROR, message, progname, &block) end
Return true
if ERROR
messages are being logged.
# File lib/lumberjack/logger.rb, line 159 def error? level <= ERROR end
Log a FATAL
message. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 144 def fatal(message = nil, progname = nil, &block) add(FATAL, message, progname, &block) end
Return true
if FATAL
messages are being logged.
# File lib/lumberjack/logger.rb, line 149 def fatal? level <= FATAL end
Flush the logging device. Messages are not guaranteed to be written until this method is called.
# File lib/lumberjack/logger.rb, line 131 def flush device.flush @last_flushed_at = Time.now nil end
Get the Formatter object used to convert messages into strings.
# File lib/lumberjack/logger.rb, line 76 def formatter @_formatter end
Log an INFO
message. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 174 def info(message = nil, progname = nil, &block) add(INFO, message, progname, &block) end
Return true
if INFO
messages are being logged.
# File lib/lumberjack/logger.rb, line 179 def info? level <= INFO end
Get the level of severity of entries that are logged. Entries with a lower severity level will be ignored.
# File lib/lumberjack/logger.rb, line 82 def level thread_local_value(:lumberjack_logger_level) || @level end
Set the minimum level of severity of messages to log.
# File lib/lumberjack/logger.rb, line 202 def level=(severity) if severity.is_a?(Fixnum) @level = severity else @level = Severity.label_to_level(severity) end end
Get the program name associated with log messages.
# File lib/lumberjack/logger.rb, line 238 def progname thread_local_value(:lumberjack_logger_progname) || @progname end
Set the program name that is associated with log messages. If a block is given, the program name will be valid only within the block.
# File lib/lumberjack/logger.rb, line 229 def set_progname(value, &block) if block push_thread_local_value(:lumberjack_logger_progname, value, &block) else self.progname = value end end
Silence the logger by setting a new log level inside a block. By default,
only ERROR
or FATAL
messages will be logged.
Example¶ ↑
logger.level = Lumberjack::Severity::INFO logger.silence do do_something # Log level inside the block is +ERROR+ end
# File lib/lumberjack/logger.rb, line 219 def silence(temporary_level = ERROR, &block) if silencer push_thread_local_value(:lumberjack_logger_level, temporary_level, &block) else yield end end
Log a message when the severity is not known. Unknown messages will always
appear in the log. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 195 def unknown(message = nil, progname = nil, &block) add(UNKNOWN, message, progname, &block) end
Log a WARN
message. The message can be passed in either the
message
argument or in a block.
# File lib/lumberjack/logger.rb, line 164 def warn(message = nil, progname = nil, &block) add(WARN, message, progname, &block) end
Return true
if WARN
messages are being logged.
# File lib/lumberjack/logger.rb, line 169 def warn? level <= WARN end