[ANN] unicorn 3.6.0 - HTTP server for fast clients and Unix

ruby-talk
1

Unicorn is an HTTP server for Rack applications designed to only serve
fast clients on low-latency, high-bandwidth connections and take
advantage of features in Unix/Unix-like kernels. Slow clients should
only be served by placing a reverse proxy capable of fully buffering
both the the request and response in between Unicorn and slow clients.

* http://unicorn.bogomips.org/
* mongrel-unicorn@rubyforge.org
* git://bogomips.org/unicorn.git

Changes: small fixes, PRNG workarounds

Mainly small fixes, improvements, and workarounds for fork() issues
with pseudo-random number generators shipped with Ruby (Kernel#rand,
OpenSSL::Random (used by SecureRandom and also by Rails).

The PRNG issues are documented in depth here (and links to Ruby Redmine):

  http://bogomips.org/unicorn.git/commit?id=1107ede7
  http://bogomips.org/unicorn.git/commit?id=b3241621

If you're too lazy to upgrade, you can just do this in your after_fork
hooks:

  after_fork do |server,worker|
    tmp = srand
    OpenSSL::Random.seed(tmp.to_s) if defined?(OpenSSL::Random)
  end

There are also small log reopening (SIGUSR1) improvements:

* relative paths may also be reopened, there's a small chance this
  will break with a handful of setups, but unlikely. This should
  make configuration easier especially since the "working_directory"
  configurator directive exists. Brought up by Matthew Kocher:
  http://thread.gmane.org/gmane.comp.lang.ruby.unicorn.general/900

* workers will just die (and restart) if log reopening fails for
  any reason (including user error). This is to workaround the issue
  reported by Emmanuel Gomez:
  http://thread.gmane.org/gmane.comp.lang.ruby.unicorn.general/906

···

--
Eric Wong

2

That was broken and made the problem worse, do this instead (or upgrade
to 3.6.1):

  after_fork do |server,worker|
    srand
    OpenSSL::Random.seed(rand.to_s) if defined?(OpenSSL::Random)
  end

This is why ruby-core should fix these problems because application
authors like me are too clumsy to be trusted :slight_smile:

···

Eric Wong <normalperson@yhbt.net> wrote:

If you're too lazy to upgrade, you can just do this in your after_fork
hooks:

  after_fork do |server,worker|
    tmp = srand
    OpenSSL::Random.seed(tmp.to_s) if defined?(OpenSSL::Random)
  end

--
Eric Wong