Module: Datadog::Profiling::Ext::Forking

Defined in:
lib/datadog/profiling/ext/forking.rb

Overview

Monkey patches ‘Kernel#fork`, adding a `Kernel#at_fork` callback mechanism which is used to restore profiling abilities after the VM forks.

Known limitations: Does not handle ‘BasicObject`s that include `Kernel` directly; e.g. `Class.new(BasicObject) { include(::Kernel); def call; fork { }; end }.new.call`.

This will be fixed once we moved to hooking into ‘Process._fork`

Defined Under Namespace

Modules: Kernel, ProcessDaemonPatch

Class Method Summary collapse

Class Method Details

.apply! ⇒ Object 



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# File 'lib/datadog/profiling/ext/forking.rb', line 16

def self.apply!
  return false unless supported?

  [
    ::Process.singleton_class, # Process.fork
    ::Kernel.singleton_class,  # Kernel.fork
    ::Object,                  # fork without explicit receiver (it's defined as a method in ::Kernel)
    # Note: Modifying Object as we do here is irreversible. During tests, this
    # change will stick around even if we otherwise stub `Process` and `Kernel`
  ].each { |target| target.prepend(Kernel) }

  ::Process.singleton_class.prepend(ProcessDaemonPatch)
end

.supported? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/datadog/profiling/ext/forking.rb', line 12

def self.supported?
  Process.respond_to?(:fork)
end