::Logging::Layout
This layout will produce parseable log output in either JSON or YAML format. This makes it much easier for machines to parse log files and perform analysis on those logs.
The information about the log event can be configured when the layout is created. Any or all of the following labels can be set as the items to log:
'logger' Used to output the name of the logger that generated the log event. 'timestamp' Used to output the timestamp of the log event. 'level' Used to output the level of the log event. 'message' Used to output the application supplied message associated with the log event. 'file' Used to output the file name where the logging request was issued. 'line' Used to output the line number where the logging request was issued. 'method' Used to output the method name where the logging request was issued. 'pid' Used to output the process ID of the currently running program. 'millis' Used to output the number of milliseconds elapsed from the construction of the Layout until creation of the log event. 'thread_id' Used to output the object ID of the thread that generated the log event. 'thread' Used to output the name of the thread that generated the log event. Name can be specified using Thread.current[:name] notation. Output empty string if name not specified. This option helps to create more human readable output for multithread application logs.
These items are supplied to the layout as an array of strings. The items ‘file’, ‘line’, and ‘method’ will only work if the Logger generating the events is configured to generate tracing information. If this is not the case these fields will always be empty.
When configured to output log events in YAML format, each log message will be formatted as a hash in it’s own YAML document. The hash keys are the name of the item, and the value is what you would expect it to be. Therefore, for the default set of times log message would appear as follows:
--- timestamp: 2009-04-17 16:15:42 level: INFO logger: Foo::Bar message: this is a log message --- timestamp: 2009-04-17 16:15:43 level: ERROR logger: Foo message: <RuntimeError> Oooops!!
The output order of the fields is not guaranteed to be the same as the order specified in the items list. This is because Ruby hashes are not ordered by default (unless you’re running this in Ruby 1.9).
When configured to output log events in JSON format, each log message will be formatted as an object (in the JSON sense of the word) on it’s own line in the log output. Therefore, to parse the output you must read it line by line and parse the individual objects. Taking the same example above the JSON output would be:
{"timestamp":"2009-04-17 16:15:42","level":"INFO","logger":"Foo::Bar","message":"this is a log message"} {"timestamp":"2009-04-17 16:15:43","level":"ERROR","logger":"Foo","message":"<RuntimeError> Oooops!!"}
The output order of the fields is guaranteed to be the same as the order specified in the items list.
Create a new Parseable layout that outputs log events using JSON style formatting. See the initializer documentation for available options.
# File lib/logging/layouts/parseable.rb, line 156 156: def self.json( opts = {} ) 157: opts[:style] = 'json' 158: new(opts) 159: end
Creates a new Parseable layout using the following options:
:style => :json or :yaml :items => %w[timestamp level logger message]
# File lib/logging/layouts/parseable.rb, line 180 180: def initialize( opts = {} ) 181: super 182: @created_at = Time.now 183: @style = opts.getopt(:style, 'json').to_s.intern 184: self.items = opts.getopt(:items, ]timestamp level logger message]) 185: end
Create a new Parseable layout that outputs log events using YAML style formatting. See the initializer documentation for available options.
# File lib/logging/layouts/parseable.rb, line 167 167: def self.yaml( opts = {} ) 168: opts[:style] = 'yaml' 169: new(opts) 170: end
Set the log event items that will be formatted by this layout. These items, and only these items, will appear in the log output.
# File lib/logging/layouts/parseable.rb, line 195 195: def items=( ary ) 196: @items = Array(ary).map {|name| name.to_s.downcase} 197: valid = DIRECTIVE_TABLE.keys 198: @items.each do |name| 199: raise ArgumentError, "unknown item - #{name.inspect}" unless valid.include? name 200: end 201: create_format_method 202: end
Call the appropriate class level create format method based on the style of this parseable layout.
# File lib/logging/layouts/parseable.rb, line 219 219: def create_format_method 220: case @style 221: when :json; Parseable.create_json_format_method(self) 222: when :yaml; Parseable.create_yaml_format_method(self) 223: else raise ArgumentError, "unknown format style '#@style'" end 224: end
Take the given value and format it into a JSON compatible string.
# File lib/logging/layouts/parseable.rb, line 208 208: def format_as_json( value ) 209: case value 210: when String, Integer, Float; value.inspect 211: when nil; 'null' 212: when Time; %{"#{iso8601_format(value)}"} 213: else %{"#{value.inspect}"} end 214: end
Convert the given time value into an ISO8601 formatted time string.
# File lib/logging/layouts/parseable.rb, line 228 228: def iso8601_format( value ) 229: str = value.strftime('%Y-%m-%dT%H:%M:%S') 230: str << ('.%06d' % value.usec) 231: 232: offset = value.gmt_offset.abs 233: return str << 'Z' if offset == 0 234: 235: offset = sprintf('%02d:%02d', offset / 3600, offset % 3600 / 60) 236: return str << (value.gmt_offset < 0 ? '-' : '+') << offset 237: end
Disabled; run with --debug to generate this.
Generated with the Darkfish Rdoc Generator 1.1.6.