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Editing: cdesc-Logger.yaml
--- !ruby/object:RI::ClassDescription attributes: - !ruby/object:RI::Attribute comment: - !ruby/struct:SM::Flow::P body: Logging formatter. formatter#call is invoked with 4 arguments; severity, time, progname and msg for each log. Bear in mind that time is a Time and msg is an Object that user passed and it could not be a String. It is expected to return a logdev#write-able Object. Default formatter is used when no formatter is set. name: formatter rw: RW - !ruby/object:RI::Attribute comment: - !ruby/struct:SM::Flow::P body: Logging severity threshold (e.g. <tt>Logger::INFO</tt>). name: level rw: RW - !ruby/object:RI::Attribute comment: - !ruby/struct:SM::Flow::P body: Logging program name. name: progname rw: RW class_methods: - !ruby/object:RI::MethodSummary name: new comment: - !ruby/struct:SM::Flow::P body: Simple logging utility. - !ruby/object:SM::Flow::LIST contents: - !ruby/struct:SM::Flow::LI label: "Author:" body: NAKAMURA, Hiroshi <nakahiro@sarion.co.jp> - !ruby/struct:SM::Flow::LI label: "Documentation:" body: NAKAMURA, Hiroshi and Gavin Sinclair - !ruby/struct:SM::Flow::LI label: "License:" body: You can redistribute it and/or modify it under the same terms of Ruby's license; either the dual license version in 2003, or any later version. - !ruby/struct:SM::Flow::LI label: "Revision:" body: "$Id: logger.rb 31806 2011-05-30 02:08:57Z nahi $" type: :NOTE - !ruby/struct:SM::Flow::H level: 2 text: Description - !ruby/struct:SM::Flow::P body: The Logger class provides a simple but sophisticated logging utility that anyone can use because it's included in the Ruby 1.8.x standard library. - !ruby/struct:SM::Flow::P body: "The HOWTOs below give a code-based overview of Logger's usage, but the basic concept is as follows. You create a Logger object (output to a file or elsewhere), and use it to log messages. The messages will have varying levels (<tt>info</tt>, <tt>error</tt>, etc), reflecting their varying importance. The levels, and their meanings, are:" - !ruby/object:SM::Flow::LIST contents: - !ruby/struct:SM::Flow::LI label: "+FATAL+:" body: an unhandleable error that results in a program crash - !ruby/struct:SM::Flow::LI label: "+ERROR+:" body: a handleable error condition - !ruby/struct:SM::Flow::LI label: "+WARN+:" body: a warning - !ruby/struct:SM::Flow::LI label: "+INFO+:" body: generic (useful) information about system operation - !ruby/struct:SM::Flow::LI label: "+DEBUG+:" body: low-level information for developers type: :NOTE - !ruby/struct:SM::Flow::P body: So each message has a level, and the Logger itself has a level, which acts as a filter, so you can control the amount of information emitted from the logger without having to remove actual messages. - !ruby/struct:SM::Flow::P body: For instance, in a production system, you may have your logger(s) set to <tt>INFO</tt> (or <tt>WARN</tt> if you don't want the log files growing large with repetitive information). When you are developing it, though, you probably want to know about the program's internal state, and would set them to <tt>DEBUG</tt>. - !ruby/struct:SM::Flow::H level: 3 text: Example - !ruby/struct:SM::Flow::P body: "A simple example demonstrates the above explanation:" - !ruby/struct:SM::Flow::VERB body: " log = Logger.new(STDOUT)\n log.level = Logger::WARN\n\n log.debug("Created logger")\n log.info("Program started")\n log.warn("Nothing to do!")\n\n begin\n File.each_line(path) do |line|\n unless line =~ /^(\\w+) = (.*)$/\n log.error("Line in wrong format: #{line}")\n end\n end\n rescue => err\n log.fatal("Caught exception; exiting")\n log.fatal(err)\n end\n" - !ruby/struct:SM::Flow::P body: Because the Logger's level is set to <tt>WARN</tt>, only the warning, error, and fatal messages are recorded. The debug and info messages are silently discarded. - !ruby/struct:SM::Flow::H level: 3 text: Features - !ruby/struct:SM::Flow::P body: There are several interesting features that Logger provides, like auto-rolling of log files, setting the format of log messages, and specifying a program name in conjunction with the message. The next section shows you how to achieve these things. - !ruby/struct:SM::Flow::H level: 2 text: HOWTOs - !ruby/struct:SM::Flow::H level: 3 text: How to create a logger - !ruby/struct:SM::Flow::P body: The options below give you various choices, in more or less increasing complexity. - !ruby/object:SM::Flow::LIST contents: - !ruby/struct:SM::Flow::LI label: "1." body: Create a logger which logs messages to STDERR/STDOUT. - !ruby/struct:SM::Flow::VERB body: " logger = Logger.new(STDERR)\n logger = Logger.new(STDOUT)\n" - !ruby/struct:SM::Flow::LI label: "2." body: Create a logger for the file which has the specified name. - !ruby/struct:SM::Flow::VERB body: " logger = Logger.new('logfile.log')\n" - !ruby/struct:SM::Flow::LI label: "3." body: Create a logger for the specified file. - !ruby/struct:SM::Flow::VERB body: " file = File.open('foo.log', File::WRONLY | File::APPEND)\n # To create new (and to remove old) logfile, add File::CREAT like;\n # file = open('foo.log', File::WRONLY | File::APPEND | File::CREAT)\n logger = Logger.new(file)\n" - !ruby/struct:SM::Flow::LI label: "4." body: Create a logger which ages logfile once it reaches a certain size. Leave 10 "old log files" and each file is about 1,024,000 bytes. - !ruby/struct:SM::Flow::VERB body: " logger = Logger.new('foo.log', 10, 1024000)\n" - !ruby/struct:SM::Flow::LI label: "5." body: Create a logger which ages logfile daily/weekly/monthly. - !ruby/struct:SM::Flow::VERB body: " logger = Logger.new('foo.log', 'daily')\n logger = Logger.new('foo.log', 'weekly')\n logger = Logger.new('foo.log', 'monthly')\n" type: :NUMBER - !ruby/struct:SM::Flow::H level: 3 text: How to log a message - !ruby/struct:SM::Flow::P body: Notice the different methods (<tt>fatal</tt>, <tt>error</tt>, <tt>info</tt>) being used to log messages of various levels. Other methods in this family are <tt>warn</tt> and <tt>debug</tt>. <tt>add</tt> is used below to log a message of an arbitrary (perhaps dynamic) level. - !ruby/object:SM::Flow::LIST contents: - !ruby/struct:SM::Flow::LI label: "1." body: Message in block. - !ruby/struct:SM::Flow::VERB body: " logger.fatal { "Argument 'foo' not given." }\n" - !ruby/struct:SM::Flow::LI label: "2." body: Message as a string. - !ruby/struct:SM::Flow::VERB body: " logger.error "Argument #{ @foo } mismatch."\n" - !ruby/struct:SM::Flow::LI label: "3." body: With progname. - !ruby/struct:SM::Flow::VERB body: " logger.info('initialize') { "Initializing..." }\n" - !ruby/struct:SM::Flow::LI label: "4." body: With severity. - !ruby/struct:SM::Flow::VERB body: " logger.add(Logger::FATAL) { 'Fatal error!' }\n" type: :NUMBER - !ruby/struct:SM::Flow::H level: 3 text: How to close a logger - !ruby/struct:SM::Flow::VERB body: " logger.close\n" - !ruby/struct:SM::Flow::H level: 3 text: Setting severity threshold - !ruby/object:SM::Flow::LIST contents: - !ruby/struct:SM::Flow::LI label: "1." body: Original interface. - !ruby/struct:SM::Flow::VERB body: " logger.sev_threshold = Logger::WARN\n" - !ruby/struct:SM::Flow::LI label: "2." body: Log4r (somewhat) compatible interface. - !ruby/struct:SM::Flow::VERB body: " logger.level = Logger::INFO\n\n DEBUG < INFO < WARN < ERROR < FATAL < UNKNOWN\n" type: :NUMBER - !ruby/struct:SM::Flow::H level: 2 text: Format - !ruby/struct:SM::Flow::P body: "Log messages are rendered in the output stream in a certain format. The default format and a sample are shown below:" - !ruby/struct:SM::Flow::P body: "Log format:" - !ruby/struct:SM::Flow::VERB body: " SeverityID, [Date Time mSec #pid] SeverityLabel -- ProgName: message\n" - !ruby/struct:SM::Flow::P body: "Log sample:" - !ruby/struct:SM::Flow::VERB body: " I, [Wed Mar 03 02:34:24 JST 1999 895701 #19074] INFO -- Main: info.\n" - !ruby/struct:SM::Flow::P body: "You may change the date and time format in this manner:" - !ruby/struct:SM::Flow::VERB body: " logger.datetime_format = "%Y-%m-%d %H:%M:%S"\n # e.g. "2004-01-03 00:54:26"\n" - !ruby/struct:SM::Flow::P body: There is currently no supported way to change the overall format, but you may have some luck hacking the Format constant. constants: - !ruby/object:RI::Constant comment: name: VERSION value: "\"1.2.6\"" - !ruby/object:RI::Constant comment: name: ProgName value: "\"#{File.basename(__FILE__)}/#{VERSION}\"" - !ruby/object:RI::Constant comment: - !ruby/struct:SM::Flow::P body: Severity label for logging. (max 5 char) name: SEV_LABEL value: "%w(DEBUG INFO WARN ERROR FATAL ANY)" full_name: Logger includes: - !ruby/object:RI::IncludedModule name: Severity instance_methods: - !ruby/object:RI::MethodSummary name: "<<" - !ruby/object:RI::MethodSummary name: add - !ruby/object:RI::MethodSummary name: close - !ruby/object:RI::MethodSummary name: datetime_format - !ruby/object:RI::MethodSummary name: datetime_format= - !ruby/object:RI::MethodSummary name: debug - !ruby/object:RI::MethodSummary name: debug? - !ruby/object:RI::MethodSummary name: error - !ruby/object:RI::MethodSummary name: error? - !ruby/object:RI::MethodSummary name: fatal - !ruby/object:RI::MethodSummary name: fatal? - !ruby/object:RI::MethodSummary name: format_message - !ruby/object:RI::MethodSummary name: format_severity - !ruby/object:RI::MethodSummary name: info - !ruby/object:RI::MethodSummary name: info? - !ruby/object:RI::MethodSummary name: log - !ruby/object:RI::MethodSummary name: unknown - !ruby/object:RI::MethodSummary name: warn - !ruby/object:RI::MethodSummary name: warn? name: Logger superclass: Object
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