CODEWITHSUNDEEP
rubylogging
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Reputation: 5070

ruby Logger formatter change message only

I want to change only the msg part of the default_formatter in Ruby 1.9.3 Logger. How can I do this?

I know that I can do

logger.formatter = proc do |severity, datetime, progname, msg|
   "[mymessage] #{msg}\n"
end

but then I lose the other default formatting of severity, datetime, progname.

Ideally I'd like to just do msg = "[mymessage] " + msg and then execute the default formatter with this new msg.

Upvotes: 1

Views: 496

Answers (1)

Wand Maker
Wand Maker

Reputation: 18762

Based on the example in documentation, one can do the following:

require 'logger'
logger = Logger.new(STDOUT)

original_formatter = Logger::Formatter.new
logger.formatter = proc { |severity, datetime, progname, msg|
  original_formatter.call(severity, datetime, progname, "[mymessage] #{msg}\n")
}

logger.debug("I am a debug msg")
logger.info("I am an info msg")

Output of program:

D, [2016-01-13T12:45:47.354261 #11512] DEBUG -- : [mymessage] I am a debug msg

I, [2016-01-13T12:45:47.354261 #11512]  INFO -- : [mymessage] I am an info msg

Upvotes: 1

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