[Twisted-web] load balancing and performance
Andrea Arcangeli
andrea at cpushare.com
Sun Jan 30 04:46:35 MST 2005
On Sun, Jan 30, 2005 at 12:26:33AM +0000, Valentino Volonghi wrote:
> It's probably also a good idea to write a balancer that works on unix
> sockets. And this means also writing a good path to which it should
> dispatch.
I already wrote something that works for me, but I'm running into
troubles with ssl. For various reasons I can't use this dirty hack
unless it covers ssl too, and before I can truly load balance the ssl
I'll need to share the session first.
Here the hack just in case somebody can find it useful (works perfectly
with http). Just make sure to leave the 8080/8081 etc.. closed by the
firewall or it'd be trivial to fake the client IP address in the logs.
Only the load balancer port must be open in the firewall. You're warned ;)
I'm not proposing this hack for merging, it doesn't even have an API to
pass to appserver.NevowSite, but this might be useful to get an hint on
how to make it work.
--- ./Nevow/nevow/appserver.py.~1~ 2005-01-29 02:12:44.000000000 +0100
+++ ./Nevow/nevow/appserver.py 2005-01-29 17:11:16.000000000 +0100
@@ -222,7 +222,8 @@ class NevowSite(server.Site):
def __init__(self, *args, **kwargs):
server.Site.__init__(self, *args, **kwargs)
self.context = context.SiteContext()
-
+ self.proxyPeer = True
+
def remember(self, obj, inter=None):
"""Remember the given object for the given interfaces (or all interfaces
obj implements) in the site's context.
--- ./Twisted/twisted/web/http.py.~1~ 2005-01-14 20:44:45.000000000 +0100
+++ ./Twisted/twisted/web/http.py 2005-01-29 17:43:56.000000000 +0100
@@ -526,7 +526,10 @@ class Request:
# cache the client and server information, we'll need this later to be
# serialized and sent with the request so CGIs will work remotely
- self.client = self.channel.transport.getPeer()
+ if not self.channel.proxyPeer:
+ self.client = self.channel.transport.getPeer()
+ else:
+ self.client = self.channel.proxyPeer
self.host = self.channel.transport.getHost()
# Argument processing
@@ -909,6 +912,7 @@ class HTTPChannel(basic.LineReceiver, po
__header = ''
__first_line = 1
__content = None
+ proxyPeer = None
# set in instances or subclasses
requestFactory = Request
@@ -921,11 +925,18 @@ class HTTPChannel(basic.LineReceiver, po
def connectionMade(self):
self.setTimeout(self.timeOut)
-
+
+ def handleProxyPeer(self, line):
+ self.proxyPeer = self.transport.getPeer()
+ self.proxyPeer.host, self.proxyPeer.port = line.split()
+
def lineReceived(self, line):
self.resetTimeout()
if self.__first_line:
+ if self.factory.proxyPeer and not self.proxyPeer:
+ self.handleProxyPeer(line)
+ return
# if this connection is not persistent, drop any data which
# the client (illegally) sent after the last request.
if not self.persistent:
@@ -1086,6 +1097,7 @@ class HTTPFactory(protocol.ServerFactory
logPath = os.path.abspath(logPath)
self.logPath = logPath
self.timeOut = timeout
+ self.proxyPeer = False
def buildProtocol(self, addr):
p = protocol.ServerFactory.buildProtocol(self, addr)
Index: pythondirector/pydirector/pdnetworktwisted.py
===================================================================
RCS file: /cvsroot/pythondirector/pythondirector/pydirector/pdnetworktwisted.py,v
retrieving revision 1.11
diff -u -p -r1.11 pdnetworktwisted.py
--- pythondirector/pydirector/pdnetworktwisted.py 14 Dec 2004 13:31:39 -0000 1.11
+++ pythondirector/pydirector/pdnetworktwisted.py 29 Jan 2005 16:49:56 -0000
@@ -58,7 +58,7 @@ class Sender(Protocol):
"""
if self.receiver is not None:
if reason.type is twisted.internet.error.ConnectionDone:
- return
+ pass
elif reason.type is twisted.internet.error.ConnectionLost:
pass
else:
@@ -78,7 +78,8 @@ class Sender(Protocol):
we've connected to the destination server. tell the other end
it's ok to send any buffered data from the client.
"""
- #print "client connection",self.factory
+ peer = self.receiver.transport.getPeer()
+ self.transport.write('%s %s\r\n' % (peer.host, peer.port))
if self.receiver.receiverOk:
self.receiver.setSender(self)
else:
> Tell me more about the session daemon. Anyway we are designing an
> ISessionManager interface to let you write whatever sessionFactory you
> need, a database or a SessionDaemon or a file or something else.
> Probably you can help with it by coming in #twisted.web and commenting
> it with one of us (Donovan, Matt, Tv, me and others).
You're right. I'm having an hard time to use #irc because I'm doing this
in my spare time, often at weird times, I can't work on this during the
day or I would go bankrupt ;).
> > Perhaps I'm going with wrong priorities though, the major offender is
> > compy, compy must be dropped from Nevow ASAP :). Leaving it as a
>
> compy is not going away :). Writing a compy2 speedup in Pyrex will
> help and will probably also be faster than zope.interface since it
> will be a lot smaller.
I diagree, see other email for the details on the reasoning of my
disagreement ;).
> zope.interface is twice as fast without the compatibility stuff in
> twisted and I think it is the same for Nevow.
So let's use zope.interfaces. I don't care if we pass through twisted,
especially if raw zope.interfaces is faster and twisted depends on it
anyway, we should probably avoid passing through twisted. But like
twisted is giving it up to use its own implementation, we should give it
up to use our implementation.
The twice as fast will translate in thousand times faster. This thing
gets called thousand of times per page or similar. I get 100000 calls
of the deprecated API in a trivial workload, so much that removing the
deprecation warning one liner that I posted some day ago, is already a
double digit percent boost ;).
So I believe it worth a try, and eliminating duplicated code sure cannot
make things worse in the long run ;).
> > Secondly I'm looking into caching the html and to render some fragment only
> > once every 10 seconds in the background (so the downloads will never
> > have to wait for a rendering of some mostly static fragment anymore).
>
> I wrote this VERY simple stuff for caching a page:
>
> Index: rend.py
> ===================================================================
> --- rend.py (revision 1105)
> +++ rend.py (working copy)
> @@ -30,6 +30,7 @@
> from nevow import flat
> from nevow.util import log
> from nevow import util
> +from nevow import url
>
> import formless
> from formless import iformless
> @@ -376,6 +377,7 @@
> self.children = {}
> self.children[name] = child
>
> +_CACHE = {}
>
> class Page(Fragment, ConfigurableFactory, ChildLookupMixin):
> """A page is the main Nevow resource and renders a document loaded
> @@ -417,7 +419,8 @@
> io = StringIO()
> writer = io.write
> def finisher(result):
> - request.write(io.getvalue())
> + c = _CACHE[url.fromContext(ctx)] = io.getvalue()
> + request.write(c)
> finishRequest()
> return result
> else:
> @@ -425,12 +428,17 @@
> def finisher(result):
> finishRequest()
> return result
> + c = _CACHE.get(url.fromContext(ctx), None)
> + if c is None:
> + doc = self.docFactory.load()
> + ctx = WovenContext(ctx, tags.invisible[doc])
> +
> + return self.flattenFactory(doc, ctx, writer, finisher)
> + else:
> + request.write(c)
> + finishRequest()
> + return c
>
> - doc = self.docFactory.load()
> - ctx = WovenContext(ctx, tags.invisible[doc])
> -
> - return self.flattenFactory(doc, ctx, writer, finisher)
> -
> def rememberStuff(self, ctx):
> Fragment.rememberStuff(self, ctx)
> ctx.remember(self, inevow.IResource)
>
> This works and I've tested it.
>
> Rendering speed went from 6-7 requests/sec to 26 req/sec on my poor ibook with the database on the same computer and ab too.
This is great, I'll play with this code very soon. This is a much more
significant optimization than the load balancer, with the load balancer
I could only double the number of pages per second.
> This patch is simple, probably too simple (in fact it would be better
> to cache the flattening result, this would be a lot more fine grained)
> since it only works in buffered mode (patching this patch to work in
> non buffered mode is not hard at all though)
No problem, it's still a good start ;).
> > So overall there's an huge room for improvements. What do other people
> > think?
>
> I also think that the optimizations branch is worth of some
> experimentation. I got twice the rendering speed in dynamic pages
> thanks to its adapters caching. I'd give it a try.
>
> Overall I think nevow can, and will, speedup at least by a factor of
> 5.
Sounds great, thanks!
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