| author |
Steve Losh <steve@stevelosh.com> |
| date |
Tue, 02 Mar 2010 19:45:54 -0500 |
| parents |
(none) |
| children |
(none) |
"""Adapt an HTTP server."""
import time
class ServerAdapter(object):
"""Adapter for an HTTP server.
If you need to start more than one HTTP server (to serve on multiple
ports, or protocols, etc.), you can manually register each one and then
start them all with bus.start:
s1 = ServerAdapter(bus, MyWSGIServer(host='0.0.0.0', port=80))
s2 = ServerAdapter(bus, another.HTTPServer(host='127.0.0.1', SSL=True))
s1.subscribe()
s2.subscribe()
bus.start()
"""
def __init__(self, bus, httpserver=None, bind_addr=None):
self.bus = bus
self.httpserver = httpserver
self.bind_addr = bind_addr
self.interrupt = None
self.running = False
def subscribe(self):
self.bus.subscribe('start', self.start)
self.bus.subscribe('stop', self.stop)
def unsubscribe(self):
self.bus.unsubscribe('start', self.start)
self.bus.unsubscribe('stop', self.stop)
def start(self):
"""Start the HTTP server."""
if self.bind_addr is None:
on_what = "unknown interface (dynamic?)"
elif isinstance(self.bind_addr, tuple):
host, port = self.bind_addr
on_what = "%s:%s" % (host, port)
else:
on_what = "socket file: %s" % self.bind_addr
if self.running:
self.bus.log("Already serving on %s" % on_what)
return
self.interrupt = None
if not self.httpserver:
raise ValueError("No HTTP server has been created.")
# Start the httpserver in a new thread.
if isinstance(self.bind_addr, tuple):
wait_for_free_port(*self.bind_addr)
import threading
t = threading.Thread(target=self._start_http_thread)
t.setName("HTTPServer " + t.getName())
t.start()
self.wait()
self.running = True
self.bus.log("Serving on %s" % on_what)
start.priority = 75
def _start_http_thread(self):
"""HTTP servers MUST be running in new threads, so that the
main thread persists to receive KeyboardInterrupt's. If an
exception is raised in the httpserver's thread then it's
trapped here, and the bus (and therefore our httpserver)
are shut down.
"""
try:
self.httpserver.start()
except KeyboardInterrupt, exc:
self.bus.log("<Ctrl-C> hit: shutting down HTTP server")
self.interrupt = exc
self.bus.exit()
except SystemExit, exc:
self.bus.log("SystemExit raised: shutting down HTTP server")
self.interrupt = exc
self.bus.exit()
raise
except:
import sys
self.interrupt = sys.exc_info()[1]
self.bus.log("Error in HTTP server: shutting down",
traceback=True, level=40)
self.bus.exit()
raise
def wait(self):
"""Wait until the HTTP server is ready to receive requests."""
while not getattr(self.httpserver, "ready", False):
if self.interrupt:
raise self.interrupt
time.sleep(.1)
# Wait for port to be occupied
if isinstance(self.bind_addr, tuple):
host, port = self.bind_addr
wait_for_occupied_port(host, port)
def stop(self):
"""Stop the HTTP server."""
if self.running:
# stop() MUST block until the server is *truly* stopped.
self.httpserver.stop()
# Wait for the socket to be truly freed.
if isinstance(self.bind_addr, tuple):
wait_for_free_port(*self.bind_addr)
self.running = False
self.bus.log("HTTP Server %s shut down" % self.httpserver)
else:
self.bus.log("HTTP Server %s already shut down" % self.httpserver)
stop.priority = 25
def restart(self):
"""Restart the HTTP server."""
self.stop()
self.start()
class FlupFCGIServer(object):
"""Adapter for a flup.server.fcgi.WSGIServer."""
def __init__(self, *args, **kwargs):
if kwargs.get('bindAddress', None) is None:
import socket
if not hasattr(socket.socket, 'fromfd'):
raise ValueError(
'Dynamic FCGI server not available on this platform. '
'You must use a static or external one by providing a '
'legal bindAddress.')
self.args = args
self.kwargs = kwargs
self.ready = False
def start(self):
"""Start the FCGI server."""
# We have to instantiate the server class here because its __init__
# starts a threadpool. If we do it too early, daemonize won't work.
from flup.server.fcgi import WSGIServer
self.fcgiserver = WSGIServer(*self.args, **self.kwargs)
# TODO: report this bug upstream to flup.
# If we don't set _oldSIGs on Windows, we get:
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 108, in run
# self._restoreSignalHandlers()
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 156, in _restoreSignalHandlers
# for signum,handler in self._oldSIGs:
# AttributeError: 'WSGIServer' object has no attribute '_oldSIGs'
self.fcgiserver._installSignalHandlers = lambda: None
self.fcgiserver._oldSIGs = []
self.ready = True
self.fcgiserver.run()
def stop(self):
"""Stop the HTTP server."""
# Forcibly stop the fcgi server main event loop.
self.fcgiserver._keepGoing = False
# Force all worker threads to die off.
self.fcgiserver._threadPool.maxSpare = self.fcgiserver._threadPool._idleCount
self.ready = False
class FlupSCGIServer(object):
"""Adapter for a flup.server.scgi.WSGIServer."""
def __init__(self, *args, **kwargs):
self.args = args
self.kwargs = kwargs
self.ready = False
def start(self):
"""Start the SCGI server."""
# We have to instantiate the server class here because its __init__
# starts a threadpool. If we do it too early, daemonize won't work.
from flup.server.scgi import WSGIServer
self.scgiserver = WSGIServer(*self.args, **self.kwargs)
# TODO: report this bug upstream to flup.
# If we don't set _oldSIGs on Windows, we get:
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 108, in run
# self._restoreSignalHandlers()
# File "C:\Python24\Lib\site-packages\flup\server\threadedserver.py",
# line 156, in _restoreSignalHandlers
# for signum,handler in self._oldSIGs:
# AttributeError: 'WSGIServer' object has no attribute '_oldSIGs'
self.scgiserver._installSignalHandlers = lambda: None
self.scgiserver._oldSIGs = []
self.ready = True
self.scgiserver.run()
def stop(self):
"""Stop the HTTP server."""
self.ready = False
# Forcibly stop the scgi server main event loop.
self.scgiserver._keepGoing = False
# Force all worker threads to die off.
self.scgiserver._threadPool.maxSpare = 0
def client_host(server_host):
"""Return the host on which a client can connect to the given listener."""
if server_host == '0.0.0.0':
# 0.0.0.0 is INADDR_ANY, which should answer on localhost.
return '127.0.0.1'
if server_host == '::':
# :: is IN6ADDR_ANY, which should answer on localhost.
return '::1'
return server_host
def check_port(host, port, timeout=1.0):
"""Raise an error if the given port is not free on the given host."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
host = client_host(host)
port = int(port)
import socket
# AF_INET or AF_INET6 socket
# Get the correct address family for our host (allows IPv6 addresses)
try:
info = socket.getaddrinfo(host, port, socket.AF_UNSPEC,
socket.SOCK_STREAM)
except socket.gaierror:
if ':' in host:
info = [(socket.AF_INET6, socket.SOCK_STREAM, 0, "", (host, port, 0, 0))]
else:
info = [(socket.AF_INET, socket.SOCK_STREAM, 0, "", (host, port))]
for res in info:
af, socktype, proto, canonname, sa = res
s = None
try:
s = socket.socket(af, socktype, proto)
# See http://groups.google.com/group/cherrypy-users/
# browse_frm/thread/bbfe5eb39c904fe0
s.settimeout(timeout)
s.connect((host, port))
s.close()
raise IOError("Port %s is in use on %s; perhaps the previous "
"httpserver did not shut down properly." %
(repr(port), repr(host)))
except socket.error:
if s:
s.close()
def wait_for_free_port(host, port):
"""Wait for the specified port to become free (drop requests)."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
for trial in range(50):
try:
# we are expecting a free port, so reduce the timeout
check_port(host, port, timeout=0.1)
except IOError:
# Give the old server thread time to free the port.
time.sleep(0.1)
else:
return
raise IOError("Port %r not free on %r" % (port, host))
def wait_for_occupied_port(host, port):
"""Wait for the specified port to become active (receive requests)."""
if not host:
raise ValueError("Host values of '' or None are not allowed.")
for trial in range(50):
try:
check_port(host, port)
except IOError:
return
else:
time.sleep(.1)
raise IOError("Port %r not bound on %r" % (port, host))