I can't speak for other use cases as I haven't directly investigated them, but
to those questions:

Apache was only an example. Any webserver that uses WSGI (whether mod_wsgi or
otherwise) doesn't support websockets. As for pushing to get it into the WSGI
standard, there's already work in that direction but amending the standard and
*then* getting all the implementations to update, etc. is a LONG way off.

If (disclaimer: these are not final details, I'm just blue-sky throwing out
possibilities) we were implementing websockets for the dashboard via node.js, we
would likely run node.js with socket.io and the "express" web framework so it
acts as its own async server on its own port. This is a pretty common setup,
very lightweight, and with minimal dependencies. It would run side-by-side with
the traditional webserver (Apache/nginx) for wsgi/python. This is down the road
for Horizon, though.

- Gabriel

From: openstack-bounces+gabriel.hurley=nebu...@lists.launchpad.net
[mailto:openstack-bounces+gabriel.hurley=nebu...@lists.launchpad.net] On
Behalf Of Adam Young Sent: Friday, May 25, 2012 3:57 PM To: open...@lists.launchpad.net Subject: Re: [Openstack] Fwd: Nodejs in horizon

We are using Eventlet as a Webserver, not apache, and Eventlet does have
websocket support.

When using Node.js do we need to run an alternative Server than the Apache HTTPD
for Dashboard?

We are looking at Websockets issues for noVNC already. One Potential approach
is to use an Apache module for Websockets: I am aware that mod_wsgi will not
handle it. Perhaps getting websocket support into mod_wsgi is a better way
forward?

On 05/25/2012 01:54 PM, Gabriel Hurley wrote: To elucidate a few more points from people's responses so far:

* All the python socket.io backends are immature projects, and there's a
GAPING flaw with them all: WSGI (the interface between web servers and Python)
doesn't support the handshake features that websocket communication requires.
The WSGI standard was drafted before websockets was a thing. There's a gevent
lib that supports it, but it's also immature and doesn't play nice with Apache,
etc. Deployment will get *really* iteresting trying to use socket.io with
Python. I've tried. ;-)

* Pypy *is* fast (I know several of the main contributors) but it's as
big a decision to use Pypy as it is to use node, but that only affects
performance. It doesn't make Django any more suited to real-time communication.
Pypy is also a major new dependency that's not packaged and it changes a lot of
things. It's also used by several orders of magnitude fewer people than node.js
currently, so security there is a whole different concern.

* Tornado and Twisted are both non-blocking web servers in Python, but
both projects have serious peculiarities which we could dive into separately.
And ultimately they're not tools any of the Horizon contributors I've talked to
so far are interested in working with, which in an open source community is
pretty much a death knell for that solution.

* John P's point about Javascript already being a core language used in
Horizon is well taken. I get the "server-side javascript is different" mindset,
but language-bashing for the sake of "I don't like javascript" is no more
helpful than Python people bashing Ruby. The fact is that Javascript as a
language is extremely similar to Python in its syntax and construction (I often
write my JS to PEP8 standards), and though it's not as readable as Python (what
is?), there's no reason JS code is inherently bad. Bad programmers write bad
code. Bad frameworks encourage bad code. Node.js suffers from neither.

* I'm 100% in favor of code-bundling only being a short-term solution.
When a reasonable number of distros package things like LESS, dropping our
bundled version in favor of a properly-versioned package would be awesome. The
fewer things to maintain the better.

All the best,

- Gabriel

From:
openstack-bounces+gabriel.hurley=nebu...@lists.launchpad.net<mailto:openstack-bounces+gabriel.hurley=nebu...@lists.launchpad.net>
[mailto:openstack-bounces+gabriel.hurley=nebu...@lists.launchpad.net] On
Behalf Of John Postlethwait Sent: Friday, May 25, 2012 9:23 AM To: Simon G.; Jay Pipes Cc: open...@lists.launchpad.net<mailto:open...@lists.launchpad.net> Subject: Re: [Openstack] Fwd: Nodejs in horizon

Hi Everyone,

Sorry if I've missed anything below, this thread has become rather fragmented
and messy (at least in my email clients) but I will try to address the main
points I have seen so far:

* Just so that everyone is aware, the lessc parser that is bundled in
Horizon, while executable, is NOT a binary. It is, in fact, just a 140 line JS
file, you can see the code here:
https://review.openstack.org/#/c/7367/4/bin/less/lessc * The reason I have bundled it within the Horizon code, as Gabriel
mentioned, is to assuage any version mismatches or install issues with LESS
itself that may arise from having yet another dependency on top of NodeJS that
needs manual steps to install. Also, the LESS package that exists for Ubuntu is
a year out of date, and other distributions do not even have packages for it. I
would love if we could rely on the OS' packages to assuage this dependency, but
we cannot, so this is the simplest and best-working solution I could think of.
It will be no more difficult to maintain than jQuery, or Bootstrap, in the
Horizon code-base... * As for distribution support, Node can be installed on just about anything,
see here:
https://github.com/joyent/node/wiki/Installing-Node.js-via-package-manager * As to the concerns about "it not being Python" or "JavaScript has been
abused." Well, all I can say to that is no, it is not Python, and yes, some
developers write terrible and abusive code with JavaScript. I'm sure I could
find horrid/abusive Python somewhere as well, but doing so would not preclude
our reasons to use it in OpenStack. Misuse of a tool is not a reason to fear the
tool itself, if that were so none of us would use any language, ever. Not to
mention, we already use a ton of JS in Horizon... I'm not introducing JavaScript
to Horizon for the first time or anything here.

I'm sure I've missed some good points, but this thread is a mess and is
difficult to sort through... :P

-John Postlethwait

________________________________ From:
openstack-bounces+john.postlethwait=nebu...@lists.launchpad.net<mailto:openstack-bounces+john.postlethwait=nebu...@lists.launchpad.net>
[openstack-bounces+john.postlethwait=nebu...@lists.launchpad.net<mailto:openstack-bounces+john.postlethwait=nebu...@lists.launchpad.net>]
on behalf of Simon G. [semy...@gmail.com<mailto:semy...@gmail.com>] Sent: Friday, May 25, 2012 7:40 AM To: Jay Pipes Cc: open...@lists.launchpad.net<mailto:open...@lists.launchpad.net> Subject: Re: [Openstack] Fwd: Nodejs in horizon Maybe I've misuderstood something, but I've tried to give examples of other
backends than node.js which can make use of mentioned before
socket.io<http://socket.io> and can be used to implement realtime communication.
I just wanted to minimize use of node.js. Hmm... I'm still talking about
realtime communication, but it was only mentioned as an example and it's not
even listed as a feature anywhere. So maybe my part in this topic is pointless.
I'll be silent from now :)

Cheers, On Fri, May 25, 2012 at 3:20 PM, Jay Pipes
<jayp...@gmail.com<mailto:jayp...@gmail.com>> wrote: On 05/25/2012 08:41 AM, Simon G. wrote: Hello,

I don't want to be rude, but fast research about point *3c* and sockets => PyPi search <http://pypi.python.org/pypi?%3Aaction=search&term=socket.io&submit=search>

* http://pypi.python.org/pypi/SocketTornad.IO/ * http://pypi.python.org/pypi/TornadIO2/0.0.3 , https://github.com/MrJoes/tornadio2 * http://pypi.python.org/pypi/django-socketio/0.3.3 * http://mrjoes.github.com/2011/12/15/sockjs-bench.html

How mature are those projects? I don't know. I'm not an expert in python. I'm just trying to find alternatives to Node.js if almost everything is in python. I'm just testing Openstack and right now I'm trying to add something to nova, but I really like horizon and if it's possible, I'd like to avoid node.js. I'm not a fan of this technology even if it's popular and fast, because I just have some doubts about Javascript and its maintainability.

Hi Simon,

socket.io<http://socket.io> is a Javascript library :) 3 of the 4 projects you
reference above use socket.io<http://socket.io>.

Best, -jay

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