Class: PhusionPassenger::Utils::UnseekableSocket

Inherits:
Object
  • Object
show all
Defined in:
lib/phusion_passenger/utils/unseekable_socket.rb

Overview

Some frameworks (e.g. Merb) call seek and rewind on the input stream if it responds to these methods. In case of Phusion Passenger, the input stream is a socket, and altough socket objects respond to seek and rewind, calling these methods will raise an exception. We don’t want this to happen so in AbstractRequestHandler we wrap the client socket into an UnseekableSocket wrapper, which doesn’t respond to these methods.

We used to dynamically undef seek and rewind on sockets, but this blows the Ruby interpreter’s method cache and made things slower. Wrapping a socket is faster despite extra method calls.

Furthermore, all exceptions originating from the wrapped socket will be annotated. One can check whether a certain exception originates from the wrapped socket by calling #source_of_exception?

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.wrap(socket) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 44

def self.wrap(socket)
	return new.wrap(socket)
end

Instance Method Details

#addr ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 94

def addr
	@socket.addr
rescue => e
	raise annotate(e)
end

#binmode ⇒ Object

Already set to binary mode.



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 87

def binmode
end

#close ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 166

def close
	@socket.close
rescue => e
	raise annotate(e)
end

#close_read ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 172

def close_read
	@socket.close_read
rescue => e
	raise annotate(e)
end

#close_write ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 178

def close_write
	@socket.close_write
rescue => e
	raise annotate(e)
end

#closed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 160

def closed?
	@socket.closed?
rescue => e
	raise annotate(e)
end

#each(&block) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 154

def each(&block)
	@socket.each(&block)
rescue => e
	raise annotate(e)
end

#flush ⇒ Object

Socket is sync’ed so flushing shouldn’t do anything.



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 83

def flush
end

#gets ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 130

def gets
	@socket.gets
rescue => e
	raise annotate(e)
end

#puts(*args) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 124

def puts(*args)
	@socket.puts(*args)
rescue => e
	raise annotate(e)
end

#read(*args) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 136

def read(*args)
	@socket.read(*args)
rescue => e
	raise annotate(e)
end

#readline ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 148

def readline
	@socket.readline
rescue => e
	raise annotate(e)
end

#readpartial(*args) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 142

def readpartial(*args)
	@socket.readpartial(*args)
rescue => e
	raise annotate(e)
end

#source_of_exception?(exception) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 184

def source_of_exception?(exception)
	return exception.instance_variable_get(:"@from_unseekable_socket") == @socket.object_id
end

#sync=(value) ⇒ Object

Don’t allow disabling of sync.



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 79

def sync=(value)
end

#to_io ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 90

def to_io
	self
end

#wrap(socket) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 48

def wrap(socket)
	# Some people report that sometimes their Ruby (MRI/REE)
	# processes get stuck with 100% CPU usage. Upon further
	# inspection with strace, it turns out that these Ruby
	# processes are continuously calling lseek() on a socket,
	# which of course returns ESPIPE as error. gdb reveals
	# lseek() is called by fwrite(), which in turn is called
	# by rb_fwrite(). The affected socket is the
	# AbstractRequestHandler client socket.
	#
	# I inspected the MRI source code and didn't find
	# anything that would explain this behavior. This makes
	# me think that it's a glibc bug, but that's very
	# unlikely.
	#
	# The rb_fwrite() implementation takes an entirely
	# different code path if I set 'sync' to true: it will
	# skip fwrite() and use write() instead. So here we set
	# 'sync' to true in the hope that this will work around
	# the problem.
	socket.sync = true
	
	# There's no need to set the encoding for Ruby 1.9 because
	# abstract_request_handler.rb is tagged with 'encoding: binary'.
	
	@socket = socket
	
	return self
end

#write(string) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 100

def write(string)
	@socket.write(string)
rescue => e
	raise annotate(e)
end

#writev(components) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 106

def writev(components)
	@socket.writev(components)
rescue => e
	raise annotate(e)
end

#writev2(components, components2) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 112

def writev2(components, components2)
	@socket.writev2(components, components2)
rescue => e
	raise annotate(e)
end

#writev3(components, components2, components3) ⇒ Object 



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# File 'lib/phusion_passenger/utils/unseekable_socket.rb', line 118

def writev3(components, components2, components3)
	@socket.writev3(components, components2, components3)
rescue => e
	raise annotate(e)
end