因采用 Flask 原生 WSGI 出现 "Broken pipe" 报错的故障处理

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Flask 出现 "Broken pipe" 现象说明：

采用 Flask 原生 WSGI 发布 Web（app.run()）。随后，发起一个 Request，在 Request 还未返回前停止查询，并重新发起一个新的 Request。服务端很可能出现类似如下的"Broken pipe"报错。

Exception in thread Thread-1:

Traceback (most recent call last):

  File "/usrb64/python2.7/threading.py", line 811, in __bootstrap_inner

    self.run()

  File "/usrb64/python2.7/threading.py", line 764, in run

    self.__target(*self.__args, **self.__kwargs)

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 659, in inner

    srv.serve_forever()

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 499, in serve_forever

    HTTPServer.serve_forever(self)

  File "/usrb64/python2.7/SocketServer.py", line 238, in serve_forever

    self._handle_request_noblock()

  File "/usrb64/python2.7/SocketServer.py", line 297, in _handle_request_noblock

    self.handle_error(request, client_address)

  File "/usrb64/python2.7/SocketServer.py", line 295, in _handle_request_noblock

    self.process_request(request, client_address)

  File "/usrb64/python2.7/SocketServer.py", line 321, in process_request

    self.finish_request(request, client_address)

  File "/usrb64/python2.7/SocketServer.py", line 334, in finish_request

    self.RequestHandlerClass(request, client_address, self)

  File "/usrb64/python2.7/SocketServer.py", line 649, in __init__

    self.handle()

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 216, in handle

    rv = BaseHTTPRequestHandler.handle(self)

  File "/usrb64/python2.7/BaseHTTPServer.py", line 340, in handle

    self.handle_one_request()

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 251, in handle_one_request

    return self.run_wsgi()

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 193, in run_wsgi

    execute(self.server.app)

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 184, in execute

    write(data)

  File "/usrb/python2.7/site-packages/werkzeugrving.py", line 152, in write

    self.send_header(key, value)

  File "/usrb64/python2.7/BaseHTTPServer.py", line 401, in send_header

    self.wfile.write("%s: %s\r\n" % (keyword, value))

IOError: [Errno 32] Broken pipe

 

"Broken pipe" 报错原因：<wiz_tmp_tag id="wiz-table-range-border" contenteditable="false" style="display: none;">

 

 

 

 

"Broken pipe" 的字面意思为 "管道破裂"，本质为写入端反馈时读端却关闭，因而造成没有及时取走管道中的数据，从而引发程序异常。

 

"Broken pipe" 报错处理方式：

放弃对 Flask 原生 WSGI 的使用，转而使用全功能的 WSGI，例如：gunicorn、uWSGI 等。

 

多种 WSGI 对引发 "Broken pip" 报错操作的响应对比：

1.Flask 原生 WSGI

采用 Flask 原生 WSGI 的最简测试程序如下。

from flask import Flask

                                                                          

app = Flask(__name__)

                                                                             

@app.route('/')

def index():

    import time

    time.sleep(10)

    return 'Hello World'

                                   

app.run(host='11.4.76.73', port=6001)

调用方式如下。

# ./env/bin/python flasktest.py

当发起一个 Request，在 Request 还未返回前停止查询，并重新发起一个新的 Request时，WSGI 响应类似如下。

注意：报错"Broken pipe"，程序崩溃。

2.gunicorn

采用 gunicorn 的最简测试程序如下。

from flask import Flask

                                     

app = Flask(__name__)

                                       

@app.route('/')

def index():

    import time

    time.sleep(10)

    return 'Hello World'

调用方式如下。

# ./env/bin/gunicorn -w 1 --log-level 'debug' -b 11.4.76.73:6002 gunicorntest:app

当发起一个 Request，在 Request 还未返回前停止查询，并重新发起一个新的 Request时，WSGI 响应类似如下。

注意：出现"Ignoring connection reset"信息，但不影响应用运行。

3.pywsgi

采用 pywsgi 的最简测试程序如下。

from gevent import monkey

monkey.patch_all()

from flask import Flask

from gevent import pywsgi

                                       

app = Flask(__name__)

                                       

@app.route('/')

def index():

    import time

    time.sleep(10)

    return 'Hello World'

                                   

server = pywsgi.WSGIServer(('11.4.76.73', 6003), app)

server.serve_forever()

调用方式如下。

# ./env/bin/python geventtest.py

当发起一个 Request，在 Request 还未返回前停止查询，并重新发起一个新的 Request时，WSGI 响应类似如下。

注意：应用正常。