Is Ruby's stdlib Logger class thread-safe?

Question

In short, is the standard library Logger class in Ruby thread-safe? Only useful info Google turned up was someone on a forum saying it \"seems\" thread-safe. And I don\'t fe

Answer 1

source

Try if logs will be mixtures in multithreads

require 'logger'
require 'parallel'

logger = Logger.new("/tmp/test.log")

Parallel.map(['a','b'], :in_threads => 2) do |letter|
  1000.times do
    logger.info letter * 5000
  end
end

Testing the log file

egrep -e 'ab' -e 'ba' /tmp/test.log
[empty]

The reason why logs didn't get mixtured:

def write(message)
  @mutex.synchronize do
    ...    
    @dev.write(message)        
  end
end