Module: Gitlab::Popen

Extended by:
Popen
Included in:
Popen
Defined in:
lib/gitlab/popen.rb,
lib/gitlab/popen/runner.rb

Defined Under Namespace

Classes: Result, Runner

Instance Method Summary collapse

Instance Method Details

#popen(cmd, path = nil, vars = {}, &block) ⇒ Object

Returns [stdout + stderr, status] status is either the exit code or the signal that killed the process


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# File 'lib/gitlab/popen.rb', line 14

def popen(cmd, path = nil, vars = {}, &block)
  result = popen_with_detail(cmd, path, vars, &block)

  # Process#waitpid returns Process::Status, which holds a 16-bit value.
  # The higher-order 8 bits hold the exit() code (`exitstatus`).
  # The lower-order bits holds whether the process was terminated.
  # If the process didn't exit normally, `exitstatus` will be `nil`,
  # but we still want a non-zero code, even if the value is
  # platform-dependent.
  status = result.status&.exitstatus || result.status.to_i

  ["#{result.stdout}#{result.stderr}", status]
end

#popen_with_detail(cmd, path = nil, vars = {}) ⇒ Object

Returns Result


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# File 'lib/gitlab/popen.rb', line 29

def popen_with_detail(cmd, path = nil, vars = {})
  unless cmd.is_a?(Array)
    raise "System commands must be given as an array of strings"
  end

  path ||= Dir.pwd
  vars['PWD'] = path
  options = { chdir: path }

  unless File.directory?(path)
    FileUtils.mkdir_p(path)
  end

  cmd_stdout = ''
  cmd_stderr = ''
  cmd_status = nil
  start = Time.now

  Open3.popen3(vars, *cmd, options) do |stdin, stdout, stderr, wait_thr|
    # stderr and stdout pipes can block if stderr/stdout aren't drained: https://bugs.ruby-lang.org/issues/9082
    # Mimic what Ruby does with capture3: https://github.com/ruby/ruby/blob/1ec544695fa02d714180ef9c34e755027b6a2103/lib/open3.rb#L257-L273
    out_reader = Thread.new { stdout.read }
    err_reader = Thread.new { stderr.read }

    yield(stdin) if block_given?
    stdin.close

    cmd_stdout = out_reader.value
    cmd_stderr = err_reader.value
    cmd_status = wait_thr.value
  end

  Result.new(cmd, cmd_stdout, cmd_stderr, cmd_status, Time.now - start)
end