Object
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.
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.
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 61 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
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.
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 98 def add(severity, message = nil, progname = nil) severity = Severity.label_to_level(severity) if severity.is_a?(String) || severity.is_a?(Symbol) if severity && severity >= level time = Time.now message = yield if message.nil? && block_given? message = @formatter.format(message) entry = LogEntry.new(time, severity, message, progname || self.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 end nil end
Close the logging device.
# File lib/lumberjack/logger.rb, line 125 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 171 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 176 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 141 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 146 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 131 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 136 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 118 def flush device.flush @last_flushed_at = Time.now nil 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 161 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 166 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 80 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 189 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 225 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 216 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.
logger.level = Lumberjack::Severity::INFO logger.silence do do_something # Log level inside the block is +ERROR+ end
# File lib/lumberjack/logger.rb, line 206 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 182 def unknown(message = nil, progname = nil, &block) add(UNKNOWN, message, progname, &block) end
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