Working ConnectionPool disconnect! on fork callbacks.

README.rdoc

@@ -1,6 +1,39 @@
 = rails_is_forked
 
-Description goes here.
+Rails does not clear ConnectionPool in Process.fork children:
+
+  puts "Parent #{$$}: #{ActiveRecord::Base.connection.object_id}"
+  fork { puts "Child: #{$$}: #{ActiveRecord::Base.connection.object_id}" }
+  Thread.new { puts "Thread: #{ActiveRecord::Base.connection.object_id}" }
+
+Sample Output:
+
+  Parent 27282: 153210860
+  Child: 29777: 153210860
+  Thread: 153076390
+
+Note that Threads get their own connections, but subprocesses do not.
+
+A ConnectionPool exists for each ActiveRecord::Base subclass that has been sent :establish_connection.
+
+  puts "Parent #{$$}: #{ActiveRecord::Base.connection_pool.object_id}"
+  fork { puts "Child: #{$$}: #{ActiveRecord::Base.connection_pool.object_id}" }
+  Thread.new { puts "Thread: #{ActiveRecord::Base.connection_pool.object_id}" }
+
+Sample Output:
+
+Parent 30003: 102371950
+Child: 30053: 102371950
+Thread: 102371950
+
+Note that ConnectionPools are only uniq per process.
+
+This gem adds: 
+
+* RailsIsForked::ForkCallback:
+** Callbacks in children (and parents) of Process.fork (and Kernel.fork).  This is useful for non-Rails apps.
+* RailsIsForked::Rails:
+** Calls ActiveRecord::ConnectionAdapters::ConnectionPool#disconnect! for all instances in forked children.  See ActiveRecord::Base.connection_handler.connection_pools.
 
 == Contributing to rails_is_forked
 

cabar.yml

@@ -0,0 +1,16 @@
+cabar:
+  version: v1.0
+
+  component:
+    version: v1.0
+    description: 'rails_is_forked - Create new DB connections in forked children.'
+
+  provides:
+    bin: true
+    lib/ruby: lib
+    cnu_config_path: true
+    tests: spec
+
+  requires:
+    component:
+      ruby: true

lib/rails_is_forked/rails.rb

@@ -0,0 +1,28 @@
+require 'rails_is_forked/fork_callback'
+
+require 'active_record/connection_adapters/abstract/connection_pool'
+
+module RailsIsForked
+  module ConnectionPoolDisconnectOnFork
+    @@once = false
+
+    def self.included target
+      super
+
+      return if @@once
+      @@once = true
+
+      # Register callback to call ConnectionPool#disconnect! on all instances.
+      proc = RailsIsForked::ForkCallback.add_callback_in_child! do | child_pid |
+        ActiveRecord::Base.connection_handler.connection_pools.each_value do | pool |
+          # $stderr.puts "#{$$}: #{pool}.disconnect!"
+          pool.disconnect!
+        end
+      end
+      # $stderr.puts "Registered callback #{proc}"
+    end
+
+   ::ActiveRecord::ConnectionAdapters::ConnectionPool.send(:include, self)
+  end
+end
+