class WebApplicationService(StreamServerEndpointService):
"""Service encapsulating the Django web application.
This shows a default "MAAS is starting" web page until Django is up. If
Django cannot be started, the page is replaced by the error that caused
start-up to fail.
:ivar site: The site object that wraps a WSGI resource.
:ivar threadpool: The thread-pool used for servicing requests to
the web application.
"""
def __init__(self, port, listener, status_worker):
self.port = port
self.starting = False
# Start with an empty `Resource`, `installApplication` will configure
# the root resource. This must be seperated because Django must be
# start from inside a thread with database access.
self.site = OverlaySite(
Resource(), logFormatter=reducedWebLogFormatter, timeout=None
)
self.site.requestFactory = CleanPathRequest
# `endpoint` is set in `privilegedStartService`, at this point the
# `endpoint` is None.
super(WebApplicationService, self).__init__(None, self.site)
self.websocket = WebSocketFactory(listener)
self.threadpool = ThreadPoolLimiter(
reactor.threadpoolForDatabase, concurrency.webapp
)
self.status_worker = status_worker
def prepareApplication(self):
"""Return the WSGI application.
If we run servers on multiple endpoints this ought to be extracted
into a separate function, so that each server uses the same
application.
"""
return WebApplicationHandler()
def startWebsocket(self):
"""Start the websocket factory for the `WebSocketsResource`."""
self.websocket.startFactory()
def installApplication(self, application):
"""Install the WSGI application into the Twisted site.
It's installed as a child with path "MAAS". This matches the default
front-end configuration (i.e. Apache) so that there's no need to force
script names.
"""
# Setup resources to process paths that twisted handles.
metadata = Resource()
metadata.putChild(b"status", StatusHandlerResource(self.status_worker))
maas = Resource()
maas.putChild(b"metadata", metadata)
maas.putChild(b"static", File(settings.STATIC_ROOT))
maas.putChild(
b"ws", WebSocketsResource(lookupProtocolForFactory(self.websocket))
)
root = Resource()
root.putChild(b"", Redirect(b"MAAS/"))
root.putChild(b"MAAS", maas)
# Setup the resources to process paths that django handles.
underlay_maas = ResourceOverlay(
WSGIResource(reactor, self.threadpool, application)
)
underlay_root = Resource()
underlay_root.putChild(b"MAAS", underlay_maas)
underlay_site = Site(
underlay_root, logFormatter=reducedWebLogFormatter
)
underlay_site.requestFactory = CleanPathRequest
# Setup the main resource as the twisted handler and the underlay
# resource as the django handler.
self.site.resource = root
self.site.underlay = underlay_site
@inlineCallbacks
def startApplication(self):
"""Start the Django application, and install it."""
application = yield deferToDatabase(self.prepareApplication)
self.startWebsocket()
self.installApplication(application)
def _makeEndpoint(self):
"""Make the endpoint for the webapp."""
# Make a socket with SO_REUSEPORT set so that we can run multiple web
# applications. This is easier to do from outside of Twisted as there's
# not yet official support for setting socket options.
s = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
# N.B, using the IPv6 INADDR_ANY means that getpeername() returns
# something like: ('::ffff:192.168.133.32', 40588, 0, 0)
s.bind(("::", self.port))
# Use a backlog of 50, which seems to be fairly common.
s.listen(50)
# Adopt this socket into Twisted's reactor setting the endpoint.
endpoint = AdoptedStreamServerEndpoint(reactor, s.fileno(), s.family)
endpoint.port = self.port # Make it easy to get the port number.
endpoint.socket = s # Prevent garbage collection.
return endpoint
@asynchronous(timeout=30)
@inlineCallbacks
def privilegedStartService(self):
# Twisted will call `privilegedStartService` followed by `startService`
# that also calls `privilegedStartService`. Since this method now
# performs start-up work its possible that it will be called twice.
# Then endpoint can only be created once or a bad file descriptor
# error will occur.
if self.starting:
return
self.starting = True
# Start the application first before starting the service. This ensures
# that the application is running correctly before any requests
# can be handled.
yield self.startApplication()
# Create the endpoint now that the application is started.
self.endpoint = self._makeEndpoint()
# Start the service now that the endpoint has been created.
super(WebApplicationService, self).privilegedStartService()
@asynchronous(timeout=30)
def stopService(self):
def _cleanup(_):
self.starting = False
d = super(WebApplicationService, self).stopService()
d.addCallback(lambda _: self.websocket.stopFactory())
d.addCallback(_cleanup)
return d
class WebApplicationService(StreamServerEndpointService):
"""Service encapsulating the Django web application.
This shows a default "MAAS is starting" web page until Django is up. If
Django cannot be started, the page is replaced by the error that caused
start-up to fail.
:ivar site: The site object that wraps a WSGI resource.
:ivar threadpool: The thread-pool used for servicing requests to
the web application.
"""
def __init__(self, endpoint, listener, status_worker):
self.site = OverlaySite(StartPage(),
logFormatter=reducedWebLogFormatter)
self.site.requestFactory = CleanPathRequest
super(WebApplicationService, self).__init__(endpoint, self.site)
self.websocket = WebSocketFactory(listener)
self.threadpool = ThreadPoolLimiter(reactor.threadpoolForDatabase,
concurrency.webapp)
self.status_worker = status_worker
def prepareApplication(self):
"""Return the WSGI application.
If we run servers on multiple endpoints this ought to be extracted
into a separate function, so that each server uses the same
application.
"""
return WebApplicationHandler()
def startWebsocket(self):
"""Start the websocket factory for the `WebSocketsResource`."""
self.websocket.startFactory()
def installApplication(self, application):
"""Install the WSGI application into the Twisted site.
It's installed as a child with path "MAAS". This matches the default
front-end configuration (i.e. Apache) so that there's no need to force
script names.
"""
# Setup resources to process paths that twisted handles.
metadata = Resource()
metadata.putChild(b'status', StatusHandlerResource(self.status_worker))
maas = Resource()
maas.putChild(b'metadata', metadata)
maas.putChild(b'static', File(settings.STATIC_ROOT))
maas.putChild(
b'ws',
WebSocketsResource(lookupProtocolForFactory(self.websocket)))
root = Resource()
root.putChild(b'', Redirect(b"MAAS/"))
root.putChild(b'MAAS', maas)
# Setup the resources to process paths that django handles.
underlay_maas = ResourceOverlay(
WSGIResource(reactor, self.threadpool, application))
underlay_root = Resource()
underlay_root.putChild(b'MAAS', underlay_maas)
underlay_site = Site(underlay_root,
logFormatter=reducedWebLogFormatter)
underlay_site.requestFactory = CleanPathRequest
# Setup the main resource as the twisted handler and the underlay
# resource as the django handler.
self.site.resource = root
self.site.underlay = underlay_site
def installFailed(self, failure):
"""Display a page explaining why the web app could not start."""
self.site.resource = StartFailedPage(failure)
log.err(failure, "MAAS web application failed to start")
def startApplication(self):
"""Start the Django application, and install it."""
try:
application = self.prepareApplication()
self.startWebsocket()
self.installApplication(application)
except:
self.installFailed(failure.Failure())
return defer.succeed(None)
@asynchronous(timeout=30)
def startService(self):
super(WebApplicationService, self).startService()
return self.startApplication()
@asynchronous(timeout=30)
def stopService(self):
d = super(WebApplicationService, self).stopService()
d.addCallback(lambda _: self.websocket.stopFactory())
return d