[英]Combining tornado and zmq ioloops: Connection reset by peer exception
當我嘗試按照pyzmq官方文檔中所述將Tornado和pyzmq ioloops組合在一起時,我遇到了一個煩人的問題(盡管不是很關鍵)。
我有一個運行龍卷風(T)服務器的進程,該進程接受來自客戶端(C)的REST API請求,並通過ZMQ傳輸到實際工作的另一個進程(Z)來代理它們。
C <-> T <-> Z
如果C 在 Z回復T 之前關閉了連接,則Z(龍卷風)會輸出一堆異常跟蹤(請參閱底部)。 想象下面的例子:
import tornado.ioloop
from tornado.web import Application, RequestHandler, asynchronous
from zmq.eventloop import ioloop
import time
def time_consuming_task():
time.sleep(5)
class TestHandler(RequestHandler):
def get(self, arg):
print "Test arg", arg
time_consuming_task()
print "Ok, time to reply"
self.write("Reply")
if __name__ == "__main__":
app = tornado.web.Application(
[
(r"/test/([0-9]+)", TestHandler)
])
ioloop.install()
app.listen(8080)
tornado.ioloop.IOLoop.instance().start()
這個示例實際上並沒有與任何ZMQ對等方交談,它只是將pyzmq ioloop附加到龍卷風的ioloop中。 雖然,足以說明問題。
從控制台一台運行服務器:
% python example.py
從控制台兩個運行客戶端,並在服務器回復之前中斷客戶端(即在5秒鍾內):
% curl -is http://localhost:8080/test/1
^C
服務器的輸出為:
Test arg 1 Ok, time to reply WARNING:root:Read error on 24: [Errno 54] Connection reset by peer ERROR:root:Uncaught exception GET /test/1 (::1) HTTPRequest(protocol='http', host='localhost:8080', method='GET', uri='/test/1', version='HTTP/1.1', remote_ip='::1', body='', headers={'Host': 'localhost:8080', 'Accept': '*/*', 'User-Agent': 'curl/7.21.4 (universal-apple-darwin11.0) libcurl/7.21.4 OpenSSL/0.9.8r zlib/1.2.5'}) Traceback (most recent call last): File "/Library/Python/2.7/site-packages/tornado/web.py", line 1023, in _execute self.finish() File "/Library/Python/2.7/site-packages/tornado/web.py", line 701, in finish self.request.finish() File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 433, in finish self.connection.finish() File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 187, in finish self._finish_request() File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 223, in _finish_request self.stream.read_until(b("\r\n\r\n"), self._header_callback) File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 153, in read_until self._try_inline_read() File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 386, in _try_inline_read if self._read_to_buffer() == 0: File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 421, in _read_to_buffer chunk = self._read_from_socket() File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 402, in _read_from_socket chunk = self.socket.recv(self.read_chunk_size) error: [Errno 54] Connection reset by peer ERROR:root:Cannot send error response after headers written ERROR:root:Uncaught exception, closing connection. Traceback (most recent call last): File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 304, in wrapper callback(*args) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 262, in _on_headers self.request_callback(self._request) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1412, in __call__ handler._execute(transforms, *args, **kwargs) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1025, in _execute self._handle_request_exception(e) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1065, in _handle_request_exception self.send_error(500, exc_info=sys.exc_info()) File "/Library/Python/2.7/site-packages/tornado/web.py", line 720, in send_error self.finish() File "/Library/Python/2.7/site-packages/tornado/web.py", line 700, in finish self.flush(include_footers=True) File "/Library/Python/2.7/site-packages/tornado/web.py", line 660, in flush self.request.write(headers + chunk, callback=callback) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 429, in write self.connection.write(chunk, callback=callback) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 177, in write assert self._request, "Request closed" AssertionError: Request closed ERROR:root:Exception in callback Traceback (most recent call last): File "/Library/Python/2.7/site-packages/pyzmq-2.2.0-py2.7-macosx-10.7-intel.egg/zmq/eventloop/ioloop.py", line 434, in _run_callback callback() File "/Library/Python/2.7/site-packages/tornado/iostream.py", line 304, in wrapper callback(*args) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 262, in _on_headers self.request_callback(self._request) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1412, in __call__ handler._execute(transforms, *args, **kwargs) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1025, in _execute self._handle_request_exception(e) File "/Library/Python/2.7/site-packages/tornado/web.py", line 1065, in _handle_request_exception self.send_error(500, exc_info=sys.exc_info()) File "/Library/Python/2.7/site-packages/tornado/web.py", line 720, in send_error self.finish() File "/Library/Python/2.7/site-packages/tornado/web.py", line 700, in finish self.flush(include_footers=True) File "/Library/Python/2.7/site-packages/tornado/web.py", line 660, in flush self.request.write(headers + chunk, callback=callback) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 429, in write self.connection.write(chunk, callback=callback) File "/Library/Python/2.7/site-packages/tornado/httpserver.py", line 177, in write assert self._request, "Request closed" AssertionError: Request closed
注意:似乎是與pyzmq相關的問題,因為排除pyzmq ioloop后消失了。
服務器不會死,它可以被其他客戶端使用,因此問題並不嚴重。 但是,在日志文件中找到這些巨大的混亂痕跡非常煩人。
那么,有沒有知名的方法可以解決這個問題呢? 謝謝。
這不是ZMQ問題。 可以出於超時以外的原因關閉請求。 ZMQ唯一的問題是它們引發了AssertionError
,這很常見,而不是更具體的異常。
如果您確定您不想在日志文件中包含這些異常,請執行以下操作:
try:
time_consuming_task()
except AssertionError as e:
if e.message == 'Request closed':
logging.info('Bad, annoying client, came to us again!')
else:
raise e
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