Use nonblocking write

[okkez]

No description provided.

[okkez]

I've not able to produce the situation explaining in #30 because fluentd is very fast and robust.
I've tested this PR using following scripts.

Run fake-server.rb and t.rb.

In previous version,
fake-server.rb cannot process so many requests and may block the request sometimes.
t.rb blocks while writing logs sometimes.

In this PR, t.rb does not block while writing logs anymore.
But set :wait_writeable to false, fluent-logger raises an error when detect IO::EAGAINWaitWritable.

fake-server.rb:

require "socket"

server = TCPServer.open("localhost", 24224)
addr = server.addr
addr.shift
puts "server is on #{addr.join(":")}"

loop do
  Thread.start(server.accept) do |s|
    puts "#{s} is accepted"
    while s.gets
      print "#{$_.size}/"
      sleep 30
    end
    puts "#{s} is gone"
    s.close
  end
end

t.rb:

require "fluent-logger"

Fluent::Logger::FluentLogger.open(nil, :host=>'localhost', :port=>24224, :wait_writeable => true)

a = []

start = Time.now

100.times do |i|
  a << Thread.start(i, j = 0) do
    loop do
      Fluent::Logger.post("myapp.access", ENV.to_hash)
      j += 1
      #puts "#{i},#{j}" if j % 1000 == 0
      print "#{i},#{j}/"
    end
  end
end

a.each(&:join)

p :done
p Time.now - start

[theindra]

+1
Hi, we ran into the same problem. Our ruby web app hangs after about 5 minutes and the profiler tells us that most of the time is spent in fluent-logger.
I think all available threads are waiting for the logger. When are you planing to release a fix for this issue

[repeatedly]

Does anyone test this patch?
We want to know this patch resolves blocking issue properly.

[dCSeven]

Are there any updates or plans to apply this patch?
I'm facing a similar problem concerning the blocking of fluentd-logger, where it would help.

[repeatedly]

We wait a response from users but no response.
So we merge this patch and release rc version soon.

[dCSeven]

Thank you

[repeatedly]

Release v0.8.0. Check https://github.com/fluent/fluent-logger-ruby#nonblocking-write