class Lumberjack::Device::Writer
This logging device writes log entries as strings to an IO stream. By
default, messages will be buffered and written to the stream in a batch
when the buffer is full or when flush
is called.
Constants
- DEFAULT_ADDITIONAL_LINES_TEMPLATE
- DEFAULT_FIRST_LINE_TEMPLATE
Attributes
The size of the internal buffer. Defaults to 32K.
Public Class Methods
Create a new device to write log entries to a stream. Entries are converted
to strings using a Template. The template
can be specified using the :template
option. This can either
be a Proc or a string that will compile into a Template object.
If the template is a Proc, it should accept an LogEntry as its only argument and output a string.
If the template is a template string, it will be used to create a Template. The :additional_lines
and :time_format
options will be passed through to the Template constuctor.
The default template is "[:time :severity :progname(:pid)
#:unit_of_work_id] :message"
with additional lines formatted as
"\n [#:unit_of_work_id] :message"
. The unit of work
id will only appear if it is present.
The size of the internal buffer in bytes can be set by providing
:buffer_size
(defaults to 32K).
# File lib/lumberjack/device/writer.rb, line 55 def initialize(stream, options = {}) @lock = Mutex.new @stream = stream @stream.sync = true if @stream.respond_to?(:sync=) @buffer = Buffer.new @buffer_size = (options[:buffer_size] || 0) template = (options[:template] || DEFAULT_FIRST_LINE_TEMPLATE) if template.respond_to?(:call) @template = template else additional_lines = (options[:additional_lines] || DEFAULT_ADDITIONAL_LINES_TEMPLATE) @template = Template.new(template, :additional_lines => additional_lines, :time_format => options[:time_format]) end end
Public Instance Methods
Set the buffer size in bytes. The device will only be physically written to when the buffer size is exceeded.
# File lib/lumberjack/device/writer.rb, line 72 def buffer_size=(value) @buffer_size = value flush end
Close the underlying stream.
# File lib/lumberjack/device/writer.rb, line 87 def close flush stream.close end
Flush the underlying stream.
# File lib/lumberjack/device/writer.rb, line 93 def flush @lock.synchronize do before_flush unless @buffer.empty? out = @buffer.join(Lumberjack::LINE_SEPARATOR) << Lumberjack::LINE_SEPARATOR begin stream.write(out) stream.flush rescue => e $stderr.write("#{e.class.name}: #{e.message}#{' at ' + e.backtrace.first if e.backtrace}") $stderr.write(out) $stderr.flush end @buffer.clear end end end
Write an entry to the stream. The entry will be converted into a string using the defined template.
# File lib/lumberjack/device/writer.rb, line 78 def write(entry) string = @template.call(entry) @lock.synchronize do @buffer << string end flush if @buffer.size >= buffer_size end
Protected Instance Methods
Callback method that will be executed before data is written to the stream. Subclasses can override this method if needed.
# File lib/lumberjack/device/writer.rb, line 115 def before_flush end
Get the underlying stream.
# File lib/lumberjack/device/writer.rb, line 124 def stream @stream end
Set the underlying stream.
# File lib/lumberjack/device/writer.rb, line 119 def stream=(stream) @stream = stream end