flask怎么开启多线程

def run(self, host=None, port=None, debug=None, **options):
 from werkzeug.serving import run_simple
 if host is None:
  host = '127.0.0.1'
 if port is None:
  server_name = self.config['SERVER_NAME']
  if server_name and ':' in server_name:
   port = int(server_name.rsplit(':', 1)[1])
  else:
   port = 5000
 if debug is not None:
  self.debug = bool(debug)
 options.setdefault('use_reloader', self.debug)
 options.setdefault('use_debugger', self.debug)
 try:
  run_simple(host, port, self, **options) #会进入这个函数
 finally:
  # reset the first request information if the development server
  # reset normally. This makes it possible to restart the server
  # without reloader and that stuff from an interactive shell.
  self._got_first_request = False

   use_debugger=False, use_evalex=True,
   extra_files=None, reloader_interval=1,
   reloader_type='auto', threaded=False,
   processes=1, request_handler=None, static_files=None,
   passthrough_errors=False, ssl_context=None):
"""Start a WSGI application. Optional features include a reloader,
multithreading and fork support.
 
This function has a command-line interface too::
 
 python -m werkzeug.serving --help
 
.. versionadded:: 0.5
 `static_files` was added to simplify serving of static files as well
 as `passthrough_errors`.
 
.. versionadded:: 0.6
 support for SSL was added.
 
.. versionadded:: 0.8
 Added support for automatically loading a SSL context from certificate
 file and private key.
 
.. versionadded:: 0.9
 Added command-line interface.
 
.. versionadded:: 0.10
 Improved the reloader and added support for changing the backend
 through the `reloader_type` parameter. See :ref:`reloader`
 for more information.
 
:param hostname: The host for the application. eg: ``'localhost'``
:param port: The port for the server. eg: ``8080``
:param application: the WSGI application to execute
:param use_reloader: should the server automatically restart the python
      process if modules were changed?
:param use_debugger: should the werkzeug debugging system be used?
:param use_evalex: should the exception evaluation feature be enabled?
:param extra_files: a list of files the reloader should watch
     additionally to the modules. For example configuration
     files.
:param reloader_interval: the interval for the reloader in seconds.
:param reloader_type: the type of reloader to use. The default is
      auto detection. Valid values are ``'stat'`` and
      ``'watchdog'``. See :ref:`reloader` for more
      information.
:param threaded: should the process handle each request in a separate
     thread?
:param processes: if greater than 1 then handle each request in a new process
     up to this maximum number of concurrent processes.
:param request_handler: optional parameter that can be used to replace
      the default one. You can use this to replace it
      with a different
      :class:`~BaseHTTPServer.BaseHTTPRequestHandler`
      subclass.
:param static_files: a list or dict of paths for static files. This works
      exactly like :class:`SharedDataMiddleware`, it's actually
      just wrapping the application in that middleware before
      serving.
:param passthrough_errors: set this to `True` to disable the error catching.
       This means that the server will die on errors but
       it can be useful to hook debuggers in (pdb etc.)
:param ssl_context: an SSL context for the connection. Either an
     :class:`ssl.SSLContext`, a tuple in the form
     ``(cert_file, pkey_file)``, the string ``'adhoc'`` if
     the server should automatically create one, or ``None``
     to disable SSL (which is the default).
"""
if not isinstance(port, int):
 raise TypeError('port must be an integer')
if use_debugger:
 from werkzeug.debug import DebuggedApplication
 application = DebuggedApplication(application, use_evalex)
if static_files:
 from werkzeug.wsgi import SharedDataMiddleware
 application = SharedDataMiddleware(application, static_files)
def log_startup(sock):
 display_hostname = hostname not in ('', '*') and hostname or 'localhost'
 if ':' in display_hostname:
  display_hostname = '[%s]' % display_hostname
 quit_msg = '(Press CTRL+C to quit)'
 port = sock.getsockname()[1]
 _log('info', ' * Running on %s://%s:%d/ %s',
   ssl_context is None and 'http' or 'https',
   display_hostname, port, quit_msg)
def inner():
 try:
  fd = int(os.environ['WERKZEUG_SERVER_FD'])
 except (LookupError, ValueError):
  fd = None
 srv = make_server(hostname, port, application, threaded,
      processes, request_handler,
      passthrough_errors, ssl_context,
      fd=fd)
 if fd is None:
  log_startup(srv.socket)
 srv.serve_forever()
if use_reloader:
 # If we're not running already in the subprocess that is the
 # reloader we want to open up a socket early to make sure the
 # port is actually available.
 if os.environ.get('WERKZEUG_RUN_MAIN') != 'true':
  if port == 0 and not can_open_by_fd:
   raise ValueError('Cannot bind to a random port with enabled '
        'reloader if the Python interpreter does '
        'not support socket opening by fd.')
 
  # Create and destroy a socket so that any exceptions are
  # raised before we spawn a separate Python interpreter and
  # lose this ability.
  address_family = select_ip_version(hostname, port)
  s = socket.socket(address_family, socket.SOCK_STREAM)
  s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  s.bind(get_sockaddr(hostname, port, address_family))
  if hasattr(s, 'set_inheritable'):
   s.set_inheritable(True)
 
  # If we can open the socket by file descriptor, then we can just
  # reuse this one and our socket will survive the restarts.
  if can_open_by_fd:
   os.environ['WERKZEUG_SERVER_FD'] = str(s.fileno())
   s.listen(LISTEN_QUEUE)
   log_startup(s)
  else:
   s.close()
 
 # Do not use relative imports, otherwise "python -m werkzeug.serving"
 # breaks.
 from werkzeug._reloader import run_with_reloader
 run_with_reloader(inner, extra_files, reloader_interval,
      reloader_type)
else:
 inner() #默认会执行

   use_debugger=False, use_evalex=True,
   extra_files=None, reloader_interval=1,
   reloader_type='auto', threaded=False,
   processes=1, request_handler=None, static_files=None,
   passthrough_errors=False, ssl_context=None):
"""Start a WSGI application. Optional features include a reloader,
multithreading and fork support.
 
This function has a command-line interface too::
 
 python -m werkzeug.serving --help
 
.. versionadded:: 0.5
 `static_files` was added to simplify serving of static files as well
 as `passthrough_errors`.
 
.. versionadded:: 0.6
 support for SSL was added.
 
.. versionadded:: 0.8
 Added support for automatically loading a SSL context from certificate
 file and private key.
 
.. versionadded:: 0.9
 Added command-line interface.
 
.. versionadded:: 0.10
 Improved the reloader and added support for changing the backend
 through the `reloader_type` parameter. See :ref:`reloader`
 for more information.
 
:param hostname: The host for the application. eg: ``'localhost'``
:param port: The port for the server. eg: ``8080``
:param application: the WSGI application to execute
:param use_reloader: should the server automatically restart the python
      process if modules were changed?
:param use_debugger: should the werkzeug debugging system be used?
:param use_evalex: should the exception evaluation feature be enabled?
:param extra_files: a list of files the reloader should watch
     additionally to the modules. For example configuration
     files.
:param reloader_interval: the interval for the reloader in seconds.
:param reloader_type: the type of reloader to use. The default is
      auto detection. Valid values are ``'stat'`` and
      ``'watchdog'``. See :ref:`reloader` for more
      information.
:param threaded: should the process handle each request in a separate
     thread?
:param processes: if greater than 1 then handle each request in a new process
     up to this maximum number of concurrent processes.
:param request_handler: optional parameter that can be used to replace
      the default one. You can use this to replace it
      with a different
      :class:`~BaseHTTPServer.BaseHTTPRequestHandler`
      subclass.
:param static_files: a list or dict of paths for static files. This works
      exactly like :class:`SharedDataMiddleware`, it's actually
      just wrapping the application in that middleware before
      serving.
:param passthrough_errors: set this to `True` to disable the error catching.
       This means that the server will die on errors but
       it can be useful to hook debuggers in (pdb etc.)
:param ssl_context: an SSL context for the connection. Either an
     :class:`ssl.SSLContext`, a tuple in the form
     ``(cert_file, pkey_file)``, the string ``'adhoc'`` if
     the server should automatically create one, or ``None``
     to disable SSL (which is the default).
"""
if not isinstance(port, int):
 raise TypeError('port must be an integer')
if use_debugger:
 from werkzeug.debug import DebuggedApplication
 application = DebuggedApplication(application, use_evalex)
if static_files:
 from werkzeug.wsgi import SharedDataMiddleware
 application = SharedDataMiddleware(application, static_files)
def log_startup(sock):
 display_hostname = hostname not in ('', '*') and hostname or 'localhost'
 if ':' in display_hostname:
  display_hostname = '[%s]' % display_hostname
 quit_msg = '(Press CTRL+C to quit)'
 port = sock.getsockname()[1]
 _log('info', ' * Running on %s://%s:%d/ %s',
   ssl_context is None and 'http' or 'https',
   display_hostname, port, quit_msg)
def inner():
 try:
  fd = int(os.environ['WERKZEUG_SERVER_FD'])
 except (LookupError, ValueError):
  fd = None
 srv = make_server(hostname, port, application, threaded,
      processes, request_handler,
      passthrough_errors, ssl_context,
      fd=fd)
 if fd is None:
  log_startup(srv.socket)
 srv.serve_forever()
if use_reloader:
 # If we're not running already in the subprocess that is the
 # reloader we want to open up a socket early to make sure the
 # port is actually available.
 if os.environ.get('WERKZEUG_RUN_MAIN') != 'true':
  if port == 0 and not can_open_by_fd:
   raise ValueError('Cannot bind to a random port with enabled '
        'reloader if the Python interpreter does '
        'not support socket opening by fd.')
 
  # Create and destroy a socket so that any exceptions are
  # raised before we spawn a separate Python interpreter and
  # lose this ability.
  address_family = select_ip_version(hostname, port)
  s = socket.socket(address_family, socket.SOCK_STREAM)
  s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  s.bind(get_sockaddr(hostname, port, address_family))
  if hasattr(s, 'set_inheritable'):
   s.set_inheritable(True)
 
  # If we can open the socket by file descriptor, then we can just
  # reuse this one and our socket will survive the restarts.
  if can_open_by_fd:
   os.environ['WERKZEUG_SERVER_FD'] = str(s.fileno())
   s.listen(LISTEN_QUEUE)
   log_startup(s)
  else:
   s.close()
 
 # Do not use relative imports, otherwise "python -m werkzeug.serving"
 # breaks.
 from werkzeug._reloader import run_with_reloader
 run_with_reloader(inner, extra_files, reloader_interval,
      reloader_type)
else:
 inner() #默认会执行

   request_handler=None, passthrough_errors=False,
   ssl_context=None, fd=None):
"""Create a new server instance that is either threaded, or forks
or just processes one request after another.
"""
if threaded and processes > 1:
 raise ValueError("cannot have a multithreaded and "
      "multi process server.")
elif threaded:
 return ThreadedWSGIServer(host, port, app, request_handler,
        passthrough_errors, ssl_context, fd=fd)
elif processes > 1:
 return ForkingWSGIServer(host, port, app, processes, request_handler,
        passthrough_errors, ssl_context, fd=fd)
else:
 return BaseWSGIServer(host, port, app, request_handler,
       passthrough_errors, ssl_context, fd=fd)

"""A WSGI server that does threading."""
multithread = True
daemon_threads = True 

"""Mix-in class to handle each request in a new thread."""
 
# Decides how threads will act upon termination of the
# main process
daemon_threads = False
 
def process_request_thread(self, request, client_address):
 """Same as in BaseServer but as a thread.
 In addition, exception handling is done here.
 """
 try:
  self.finish_request(request, client_address)
  self.shutdown_request(request)
 except:
  self.handle_error(request, client_address)
  self.shutdown_request(request)
 
def process_request(self, request, client_address):
 """Start a new thread to process the request."""
 t = threading.Thread(target = self.process_request_thread,
       args = (request, client_address))
 t.daemon = self.daemon_threads
 t.start()

print(_request_ctx_stack._local.__ident_func__())
while True:
 pass
return '<h2>hello</h2>'

if __name__ == '__main__':
   app.run(threaded=True)
 
   # app.run(processes=4)