class SocketBuffer(StateMachine):
def __init__(self, sock, max_buffer):
StateMachine.__init__(self, 'reading')
self._sock = sock
self._max_buffer = max_buffer
def __repr__(self):
return '<SocketBuffer at 0x%x: socket %s max_buffer %i>' % (
id(self), self._sock, self._max_buffer)
def setup(self):
src = self._src = SocketEventSource(self._sock)
src.stop_writing() # We'll start writing when we need to.
self.mainloop.add_event_source(src)
self._wbuf = StringBuffer()
spec = [
# state, source, event_class, new_state, callback
('reading', src, SocketReadable, 'reading', self._fill),
('reading', self, _WriteBufferNotEmpty, 'rw',
self._start_writing),
('reading', self, SocketBufferEof, 'idle', None),
('reading', self, _Close, None, self._really_close),
('rw', src, SocketReadable, 'rw', self._fill),
('rw', src, SocketWriteable, 'rw', self._flush),
('rw', self, _WriteBufferIsEmpty, 'reading', self._stop_writing),
('rw', self, SocketBufferEof, 'w', None),
('rw', self, _Close, 'wc', None),
('idle', self, _WriteBufferNotEmpty, 'w', self._start_writing),
('idle', self, _Close, None, self._really_close),
('w', src, SocketWriteable, 'w', self._flush),
('w', self, _WriteBufferIsEmpty, 'idle', self._stop_writing),
('wc', src, SocketWriteable, 'wc', self._flush),
('wc', self, _WriteBufferIsEmpty, None, self._really_close),
]
self.add_transitions(spec)
def write(self, data):
'''Put data into write queue.'''
was_empty = len(self._wbuf) == 0
self._wbuf.add(data)
if was_empty and len(self._wbuf) > 0:
self._start_writing(None, None)
self.mainloop.queue_event(self, _WriteBufferNotEmpty())
def close(self):
'''Tell state machine to terminate.'''
self.mainloop.queue_event(self, _Close())
def _report_error(self, event_source, event):
logging.error(str(event))
def _fill(self, event_source, event):
try:
data = event.sock.read(self._max_buffer)
except (IOError, OSError), e:
logging.debug(
'%s: _fill(): Exception %s from sock.read()', self, e)
return [SocketError(event.sock, e)]
if data:
self.mainloop.queue_event(self, SocketBufferNewData(data))
else:
event_source.stop_reading()
self.mainloop.queue_event(self, SocketBufferEof())
class JsonMachine(StateMachine):
'''A state machine for sending/receiving JSON messages across TCP.'''
max_buffer = 16 * 1024
def __init__(self, conn):
StateMachine.__init__(self, 'rw')
self.conn = conn
self.debug_json = False
def __repr__(self):
return '<JsonMachine at 0x%x: socket %s, max_buffer %s>' % \
(id(self), self.conn, self.max_buffer)
def setup(self):
sockbuf = self.sockbuf = SocketBuffer(self.conn, self.max_buffer)
self.mainloop.add_state_machine(sockbuf)
self._eof = False
self.receive_buf = StringBuffer()
spec = [
# state, source, event_class, new_state, callback
('rw', sockbuf, SocketBufferNewData, 'rw', self._parse),
('rw', sockbuf, SocketBufferEof, 'w', self._send_eof),
('rw', self, _Close2, None, self._really_close),
('w', self, _Close2, None, self._really_close),
]
self.add_transitions(spec)
def send(self, msg):
'''Send a message to the other side.'''
if self.debug_json:
logging.debug('JsonMachine: Sending message %s' % repr(msg))
s = json.dumps(yaml.safe_dump(msg))
if self.debug_json:
logging.debug('JsonMachine: As %s' % repr(s))
self.sockbuf.write('%s\n' % s)
def close(self):
'''Tell state machine it should shut down.
The state machine will vanish once it has flushed any pending
writes.
'''
self.mainloop.queue_event(self, _Close2())
def _parse(self, event_source, event):
data = event.data
self.receive_buf.add(data)
if self.debug_json:
logging.debug('JsonMachine: Received: %s' % repr(data))
while True:
line = self.receive_buf.readline()
if line is None:
break
line = line.rstrip()
if self.debug_json:
logging.debug('JsonMachine: line: %s' % repr(line))
msg = yaml.load(json.loads(line))
self.mainloop.queue_event(self, JsonNewMessage(msg))
def _send_eof(self, event_source, event):
self.mainloop.queue_event(self, JsonEof())
def _really_close(self, event_source, event):
self.sockbuf.close()
self._send_eof(event_source, event)
class SocketBuffer(StateMachine):
def __init__(self, sock, max_buffer):
StateMachine.__init__(self, 'reading')
self._sock = sock
self._max_buffer = max_buffer
def __repr__(self):
return '<SocketBuffer at 0x%x: socket %s max_buffer %i>' % (
id(self), self._sock, self._max_buffer)
def setup(self):
src = self._src = SocketEventSource(self._sock)
src.stop_writing() # We'll start writing when we need to.
self.mainloop.add_event_source(src)
self._wbuf = StringBuffer()
spec = [
# state, source, event_class, new_state, callback
('reading', src, SocketReadable, 'reading', self._fill),
('reading', self, _WriteBufferNotEmpty, 'rw', self._start_writing),
('reading', self, SocketBufferEof, 'idle', None),
('reading', self, _Close, None, self._really_close),
('rw', src, SocketReadable, 'rw', self._fill),
('rw', src, SocketWriteable, 'rw', self._flush),
('rw', self, _WriteBufferIsEmpty, 'reading', self._stop_writing),
('rw', self, SocketBufferEof, 'w', None),
('rw', self, _Close, 'wc', None),
('idle', self, _WriteBufferNotEmpty, 'w', self._start_writing),
('idle', self, _Close, None, self._really_close),
('w', src, SocketWriteable, 'w', self._flush),
('w', self, _WriteBufferIsEmpty, 'idle', self._stop_writing),
('wc', src, SocketWriteable, 'wc', self._flush),
('wc', self, _WriteBufferIsEmpty, None, self._really_close),
]
self.add_transitions(spec)
def write(self, data):
'''Put data into write queue.'''
was_empty = len(self._wbuf) == 0
self._wbuf.add(data)
if was_empty and len(self._wbuf) > 0:
self._start_writing(None, None)
self.mainloop.queue_event(self, _WriteBufferNotEmpty())
def close(self):
'''Tell state machine to terminate.'''
self.mainloop.queue_event(self, _Close())
def _report_error(self, event_source, event):
logging.error(str(event))
def _fill(self, event_source, event):
try:
data = event.sock.read(self._max_buffer)
except (IOError, OSError), e:
logging.debug('%s: _fill(): Exception %s from sock.read()', self,
e)
return [SocketError(event.sock, e)]
if data:
self.mainloop.queue_event(self, SocketBufferNewData(data))
else:
event_source.stop_reading()
self.mainloop.queue_event(self, SocketBufferEof())
