Module: SilentStream::Extracted

Defined in:
lib/silent_stream.rb

Overview

Extracted from:
https://github.com/rails/rails/blob/4-2-stable/activesupport/lib/active_support/core_ext/kernel/reporting.rb

Constant Summary collapse

SILENT_STREAM_NULL_DEVICE = 
if defined?(IO::NULL)
  IO::NULL
else
  # :nocov:
  Gem.win_platform? ? "NUL:" : "/dev/null"
  # :nocov:
end

Instance Method Summary collapse

Instance Method Details

#capture(stream) ⇒ Object

Captures the given stream and returns it:

stream = capture(:stdout) { puts ‘notice’ }
stream # => “notice\n”

stream = capture(:stderr) { warn ‘error’ }
stream # => “error\n”

even for subprocesses:

stream = capture(:stdout) { system(‘echo notice’) }
stream # => “notice\n”

stream = capture(:stderr) { system(‘echo error 1>&2’) }
stream # => “error\n”

This method is not thread-safe.



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# File 'lib/silent_stream.rb', line 120

def capture(stream)
  stream = stream.to_s
  captured_stream = Tempfile.new(stream)
  stream_io = eval("$#{stream}")
  origin_stream = stream_io.dup
  stream_io.reopen(captured_stream)

  yield

  stream_io.rewind
  captured_stream.read
ensure
  captured_stream.close
  captured_stream.unlink
  stream_io.reopen(origin_stream)
end

#quietly(&block) ⇒ Object

Silences both STDOUT and STDERR, even for subprocesses.

quietly { system ‘bundle install’ }

This method is not thread-safe.



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# File 'lib/silent_stream.rb', line 145

def quietly(&block)
  silence_stream(STDOUT) do
    silence_stream(STDERR, &block)
  end
end

#silence_stderr(&block) ⇒ Object

This method is not thread-safe.



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# File 'lib/silent_stream.rb', line 76

def silence_stderr(&block)
  silence_stream(STDERR, &block)
end

#silence_stream(stream) ⇒ Object

Silences any stream for the duration of the block.

silence_stream(STDOUT) do
puts ‘This will never be seen’
end

puts ‘But this will’

This method is not thread-safe.



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# File 'lib/silent_stream.rb', line 89

def silence_stream(stream)
  old_stream = stream.dup
  begin
    stream.reopen(SILENT_STREAM_NULL_DEVICE, "a+")
  rescue Exception => e
    stream.puts "[SilentStream] Unable to silence. #{e.class}: #{e.message}"
  end
  stream.sync = true
  yield
ensure
  stream.reopen(old_stream)
  old_stream.close
end