Class: ACE::ForkUtil

Inherits:
Object
  • Object
show all
Defined in:
lib/ace/fork_util.rb

Class Method Summary collapse

Class Method Details

.isolate ⇒ Object

Forks and calls a function It is expected that the function returns a JSON response Throws an exception if JSON.generate fails to generate



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# File 'lib/ace/fork_util.rb', line 13

def self.isolate
  reader, writer = IO.pipe
  pid = fork {
    # :nocov:
    success = true
    begin
      response = yield
      writer.puts JSON.generate(response)
    rescue ACE::Error => e
      writer.puts({
        msg: e.message,
        kind: e.kind,
        details: {
          class: e.class,
          backtrace: e.backtrace
        }
      }.to_json)
      success = false
    rescue Exception => e # rubocop:disable Lint/RescueException
      writer.puts({
        msg: e.message,
        kind: e.class,
        details: {
          class: e.class,
          backtrace: e.backtrace
        }
      }.to_json)
      success = false
    ensure
      writer.flush
      Process.exit! success
    end
    # :nocov:
  }
  unless pid
    warn "Could not fork"
    exit 1
  end
  writer.close
  output = reader.readlines('')[0]
  Process.wait(pid)
  if $CHILD_STATUS != 0
    error = JSON.parse(output)
    raise ACE::Error.new(error['msg'], error['kind'], error['details'])
  elsif output.nil?
    raise ACE::Error.new('spawned process returned no result', 'puppetlabs/ace/fork_util', 'no details')
  else
    JSON.parse(output)
  end
end