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PORuby: Proxy pattern, reducing method calls
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copied!<p>How do I proxy the ruby logger and keep performance?</p> <p>So, we have an requirement at work, quite reasonable. When a program is sent the signal HUP the log is flushed and restarted. </p> <pre><code>class LocalObject attr_accessor :logger def initialize context # one less method call! Yea! performance++ @logger = context.logger end def something @logger.info "Hello world" end end </code></pre> <p>The problem, is that if context.logger is reset, then @logger still points to the old one.</p> <p>So, I thought I would proxy logger:</p> <pre><code>class LoggerProxy attr_accessor :logger def debug *args @logger.send :debug, args end def info *args @logger.send :info, args end end context.logger = LoggerProxy.new context.logger.logger = Logger.new 'my_file.log' Signal.trap('HUP') { context.logger.logger = Logger.new 'my_file.log' } ... @logger = context.logger @logger.info "Hello world" </code></pre> <p>This works fine, except I've traded one method call for 2 method calls (1 accessor; which returns the logger). I still have to call LoggerProxy.:debug, :info, ..., which in turn calls the original logger! Ergo, 2 methods calls, where there was one.</p> <p>I don't want to monkey with Logger class, or overload it, because I want to use other loggers in the future, syslog, roll my own, or some such.</p> <p>Is there a way reduce the number of method calls for performance?</p> <p>-daniel</p> <p>Update: in response to a question about performance, here is the sample test.</p> <pre><code>require 'logger' require 'benchmark'; class MyLogger attr_accessor :logger def info msg @logger.info msg end end myLogger = Logger.new '/dev/null' # dev null to avoid IO issues myLoggerProxy = MyLogger.new myLoggerProxy.logger = myLogger n = 100000 Benchmark.bm do | benchmarker | # plain logger benchmarker.report { n.times { myLogger.info 'opps' } } # via accessor benchmarker.report { n.times { myLoggerProxy.logger.info 'opps' } } # via proxy benchmarker.report { n.times { myLoggerProxy.info 'opps' } } end user system total real 1.580000 0.150000 1.730000 ( 1.734956) 1.600000 0.150000 1.750000 ( 1.747969) 1.610000 0.160000 1.770000 ( 1.767886) </code></pre>

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