class Gateway(object):
_gateways = {}
_gateway_lock = RLock()
def __new__(cls, bootstrap_urls):
bootstrap_urls = tuple(sorted(bootstrap_urls))
result = cls._gateways.get(bootstrap_urls)
if result is None:
with cls._gateway_lock:
result = cls._gateways.get(bootstrap_urls)
if result is None:
result = cls._gateways[bootstrap_urls] = object.__new__(cls, bootstrap_urls)
return result
__slots__ = ('gateway_port', 'process', 'gateway', 'client', 'is_running', 'is_connected', 'output_process_thread', 'bootstrap_urls')
def _cleanup(self):
if self.process is not None:
logger.debug("Closing gateway connection to %d", getattr(self, 'gateway_port', '?'))
if self.client is not None:
try:
self.client.close()
except Exception as ex:
logger.debug("Error while closing gateway client: %s", getattr(ex, 'message', '') or str(ex))
if self.gateway is not None:
self.gateway.shutdown()
if self.process is not None:
try:
self.process.terminate()
self.process.wait()
except OSError:
pass # process already gone
self.is_connected = self.is_running = False
self.gateway_port = self.client = self.process = self.gateway = None
def _establish_connection(self, bootstrap_urls):
from . import JAVA_OPTS
self.bootstrap_urls = bootstrap_urls
self.gateway_port = self.client = self.process = self.gateway = None
for _ in xrange(3):
self._cleanup()
logger.debug("Trying to create Py4J gateway")
self.process = Popen(['java', '-cp', _jar_file] + JAVA_OPTS.split() + ['com.mojn.VoldemortPython'] + [ 'tcp://' + u for u in bootstrap_urls ],
bufsize=1, preexec_fn=_preexec,
stdout=PIPE, stderr=STDOUT)
self.is_running = False
self.output_process_thread = Thread(target=self._log_stdout, args=('Voldemort-at-' + '/'.join(bootstrap_urls), self.process))
self.output_process_thread.daemon = True
self.output_process_thread.start()
logger.debug("Process created")
for attempt in xrange(5):
if self.is_running:
break
elif attempt < 4:
time.sleep(2**attempt)
if not self.is_running:
logger.debug("JVM never started running")
continue
for attempt in xrange(5):
if self.gateway_port:
break
elif attempt < 4:
time.sleep(2**attempt)
if not self.gateway_port:
logger.debug("JVM never emitted a port number on stdout")
continue
logger.debug("Gateway up - trying to connect")
for attempt in xrange(5):
try:
self.client = _RetryOnceGatewayClient(port=self.gateway_port)
self.gateway = JavaGateway(self.client, auto_convert=False)
break
except Exception: # pylint: disable=W0703
if attempt < 4:
time.sleep(2**attempt)
if self.gateway is None:
logger.debug('Could not connect to java gateway server at port %d', self.gateway_port)
continue
logger.debug("Connected to JVM - testing gateway initialization")
for attempt in xrange(5):
try:
if self.gateway.isAlive():
self.is_connected = True
break
except Exception: # pylint: disable=W0703
if attempt < 4:
time.sleep(2**attempt)
if self.is_connected:
break
if not self.is_connected:
self._cleanup()
raise IOError('Could not establish java gateway server after trying three times')
def __init__(self, bootstrap_urls):
with self._gateway_lock:
if not getattr(self, 'is_connected', False):
self._establish_connection(bootstrap_urls)
def __getattr__(self, attribute_name):
if attribute_name in self.__slots__:
raise AttributeError('Gateway does not have an attribute called ' + attribute_name)
if not getattr(self, 'is_connected', False):
raise AttributeError('Closed Gateway does not have an attribute called ' + attribute_name)
return getattr(self.gateway, attribute_name)
def close(self):
with self._gateway_lock:
logger.debug("Sealing Java gateway to " + str(self.bootstrap_urls))
if self._gateways.get(self.bootstrap_urls) is self:
del self._gateways[self.bootstrap_urls]
logger.debug("Closing Java gateway to " + str(self.bootstrap_urls))
self._cleanup()
def __del__(self):
try:
logger.debug("Deleting Gateway object " + str(self.bootstrap_urls))
self._cleanup()
except Exception:
pass
def _log_stdout(self, proc_name, process):
process_logger = logging.getLogger(__name__ + '.' + proc_name)
stream = process.stdout
fcntl.fcntl(stream.fileno(), fcntl.F_SETFL, fcntl.fcntl(stream.fileno(), fcntl.F_GETFL) | os.O_NONBLOCK)
line = ''
while process.poll() == None:
if select.select([stream.fileno()], [], [])[0]:
line += stream.read()
while '\n' in line:
output_line, _, line = line.partition('\n')
if output_line.strip().endswith('Gateway starting'):
self.is_running = True
elif 'GatewayPort-' in output_line:
self.gateway_port = int(output_line.strip().rsplit('GatewayPort-', 1)[-1])
elif output_line:
process_logger.info(output_line)
else:
time.sleep(1)
logger.debug("Stdout exhausted. Closing gateway " + str(self.bootstrap_urls))
self._cleanup()
