Module: Daemon::Utils::Process

Defined in:
lib/onapp/engine/utils/process.rb

Class Method Summary (collapse)

Class Method Details

+ (Object) block_and_fork(prepare_block, timeout = 3, &block)

Spawn new fork, execute prepare_block within fork while blocking parent process

Purpose of this method:

  1. Parent process should wait while prepare_block executed

  2. Execute prepare_block only within fork

  3. Return pid and error. Error should be not-nil if prepare_block failed or timeout exceeded



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# File 'lib/onapp/engine/utils/process.rb', line 29

def block_and_fork(prepare_block, timeout = 3, &block)
  unless prepare_block.is_a?(Proc)
    raise TypeError,
      "Need a Proc for prepare_block for #{self}.#{__method__}"
  end
  r, w = IO.pipe
  pid = ::Process.fork do
    begin
      prepare_block.call
      w.puts('ok')
      block.call
    ensure
      exit! 1
    end
  end
  error = nil
  Timeout.timeout(timeout) do
    message = r.readline.strip
    error = message if message != 'ok'
  end
  [pid, error]
rescue Timeout::Error
  [pid, "#{timeout} seconds timeout exceeded!"]
ensure
  r.close if r
  w.close if w
end

+ (Object) find(cmd, name = nil, exclude_self: true) 



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# File 'lib/onapp/engine/utils/process.rb', line 9

def find(cmd, name = nil, exclude_self: true)
  ::Sys::ProcTable.ps
    .select do |p|
      res = p.comm == cmd
      res &&= p.cmdline.to_s.strip.match(/#{name}/) unless name.nil?
      res &&= ![::Process.ppid, ::Process.pid].include?(p.pid) if exclude_self
      res
    end
    .map(&:pid)
end