Mailman 3 December 2015 - Twisted

[Twisted-Python] ssl APIs
by meejah 21 Dec '15

21 Dec '15

I've been fooling around with the Twisted SSL APIs. I'd like to add a "loadPEM" and documentation to ssl.KeyPair; shall I open a ticket and start this, or is there a reason it doesn't have a loadPEM() like some of the other classes (or any docstrings)? It is exported as a public class in "ssl". Also I'm wondering why CertificateOptions takes actual OpenSSL objects for args, instead of the Twisted equivalents; this leads to code accessing ".original" all the time if you use Twisted APIs to load Certificate (and friends) which seems .. odd. Perhaps either a Certificate *or* the correct underlying OpenSSL object could be accepted? There also doesn't seem to be a way around importing OpenSSLCertificateAuthorities from _sslverify (i.e. "private" class) if you want to give optionsForClientTLS() more than a single certificate as trustRoot. The only way I can see is to construct one of those from a list of OpenSSL certificate instances and pass that as trustRoot= Thanks for any hints, -- meejah

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[Twisted-Python] asynchronous response
by Kevin Mcintyre 18 Dec '15

18 Dec '15

Hey - I'm confused, so nothing new :) ...but I'm running at this example and I'm scratching my head. http://twistedmatrix.com/documents/current/web/howto/web-in-60/asynchronous… I would've thought 2 requests could be served simultaneously, but when I fire off 2 requests the first received gets it's response after 5 seconds, while the second response takes 10 seconds. I think I understand what's happening, but I don't know why...and I would love an example where the subsequent request doesn't have to wait for the first request to finish. Thanks, Kevin

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[Twisted-Python] twisted.web.xmlrpc.Proxy using the new HTTP 1.1 client?
by Michael Schlenker 17 Dec '15

17 Dec '15

Hi, looking at the xmlrpc client code, it looks like it still does HTTP 1.0 only. Did anyone try to hook it up to the new HTTPConnectionPool and HTTP11ClientProtocol in twisted.web.client? How hard should it be to do that, any pointers on how to do a conversion? I'm mostly interested in the persistent connections feature of HTTP1.1 (due to TLS setup costs for new connections and burning through too many client sockets when many calls are made). Michael -- Michael Schlenker Senior Software Engineer CONTACT Software GmbH Tel.: +49 (421) 20153-80 Wiener Straße 1-3 Fax: +49 (421) 20153-41 28359 Bremen E-Mail: michael.schlenker(a)contact-software.com http://www.contact-software.com/ Registered office: Bremen, Germany Managing directors: Karl Heinz Zachries, Ralf Holtgrefe Court of register: Amtsgericht Bremen HRB 1321

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[Twisted-Python] What are the relationships between twisted.cred.portal.IRealm, Portal and avatar
by Wang Yan 17 Dec '15

17 Dec '15

I'm trying to use Twisted's HTTP basic authentication to control access to some protected resources. According to some articles, it is necessary to use three important concepts: Realm, Portal and avatar. Now I'm wondering if the Realm and avatar is one to one correspondence. Let's look at an example(http://www.red-bean.com/doc/python-twisted-web/examples/webguard.py): import sys from zope.interface import implements from twisted.python import log from twisted.internet import reactor from twisted.web import server, resource, guard from twisted.cred.portal import IRealm, Portal from twisted.cred.checkers import InMemoryUsernamePasswordDatabaseDontUse class GuardedResource(resource.Resource): """ A resource which is protected by guard and requires authentication in order to access. """ def getChild(self, path, request): return self def render(self, request): return "Authorized!" class SimpleRealm(object): """ A realm which gives out L{GuardedResource} instances for authenticated users. """ implements(IRealm) def requestAvatar(self, avatarId, mind, *interfaces): if resource.IResource in interfaces: return resource.IResource, GuardedResource(), lambda: None raise NotImplementedError() def main(): log.startLogging(sys.stdout) checkers = [InMemoryUsernamePasswordDatabaseDontUse(joe='blow')] wrapper = guard.HTTPAuthSessionWrapper( Portal(SimpleRealm(), checkers), [guard.DigestCredentialFactory('md5', 'example.com')]) reactor.listenTCP(8889, server.Site( resource = wrapper)) reactor.run() if __name__ == '__main__': main() Of course I know the SimpleRealm is used to return the corresponding resource, e.g. GuardedResource in above example. However, I don't know what to do when there lots of resources to be guarded. For example, I have GuardedResource1, GuardedResource2 and GuardedResource3, maybe they need the same or different number of parameters when they are initialized; If so, is it necessary to implement SimpleRealm1, SimpleRealm2 and SimpleRealm3, respectively?

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[Twisted-Python] having 'from_' factory method with a deferred in it.
by Sinan Nalkaya 17 Dec '15

17 Dec '15

Hi Everyone, I am developing a tiny library where you can use your gpio pins (over sysfs) in twisted way. You may find more about, on https://github.com/sardok/txgpio. I am facing with a race condition issue, where certain files are needed to be created in filesystem, by kernel, in order have the class to finish its initialization. Which means in twisted jargon, a deferred needs to be resolved in __init__ (or another method - see below) method in order to have complete object. After reading this blog post http://as.ynchrono.us/2014/12/asynchronous-object-initialization.html by Jean-Paul, i believe having 'from_' factory method which waits for those certain files to be created before creating the actual class object is the better way. However, i couldn't find a way to wait for a deferred in order to use the from_ function in the following form (which is the common form for using from_ factory methods); obj = sysfs.GPIO.from_unexported_node(*a, **kw) More or less, i am looking for some thing equivalent of 'asyncio.get_event_loop()' and 'yield from loop.run_in_executor()' as mentioned in the blog post. Thanks, Sinan.

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[Twisted-Python] PotentialZombieWarning warning message?
by pisymbol . 16 Dec '15

16 Dec '15

Hi: I'd like to adopt Twisted for a current project I'm coding up. I'm on CentOS 6.7 x86-64 using python v2.6 and the stock python-twisted-8.2.0-3.1 package built for this release. No matter what I do when trying to implement the Process protocol or use utils.getProcessOutput() directly, I always see the following warning message on the console: /usr/lib64/python2.6/site-packages/twisted/internet/utils.py:25: PotentialZombieWarning: spawnProcess called, but the SIGCHLD handler is not installed. This probably means you have not yet called reactor.run, or called reactor.run(installSignalHandler=0). You will probably never see this process finish, and it may become a zombie process. reactor.spawnProcess(p, executable, (executable,)+tuple(args), env, path) ... Is there anyway to get rid of this message? I realize I'm using an older release of twisted but I can't upgrade to the latest without incurring the cost of installing an python v2.7 or greater. My script is literally: d = utils.getProcessOutput('/bin/ls') d.addCallbacks(writeResponse, noResponse) reactor.run() etc. What am I doing wrong? -aps

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[Twisted-Python] Suggested plan for GitHub migration
by Craig Rodrigues 16 Dec '15

16 Dec '15

On Tue, Nov 17, 2015 at 8:57 AM, Adi Roiban <adi(a)roiban.ro> wrote: > > For now, the funds were raised to migrate to GitHub, so we can not use > them to do other things. > > We will stay on Trac for issues... at least for now. > > I have no idea how we can migrate to any issue tracker without losing > data if we don't have full access to the database. > It is possible to migrate to another issue tracker and not lose data. I've done Trac -> Redmine, and it works, but there was an existing migration script I could use. For migrating to a cloud based bug tracker, you would need to take every user in the existing Trac database, and see if there would be a way to map the existing users to the cloud database, such as GitHub. It's a lot of work, but possible. However, for the scope of this project, if staying with Trac for issues is what is required, that is fine. > We don't plan to migrate to GitHub Issues / GitHub Wiki / GitHub Pages > > OK. So based on what you have listed, I would say that most of the work will be working with Git post commit hooks. I would say the plan should be something like this. A.1 https://github.com/twisted/twisted will be the "repository of truth" for Twisted. -> Twisted releases will be done from GitHub -> the Twisted developers who are now "core committers" for SVN, must be given access to be "core committers" to https://github.com/twisted/twisted A.2 On the Trac server, a local git mirror of the GitHub must be set up. Every bug tracker I've seen that integrates with git needs a local mirror of the repo in order to parse the git history in order to update the bug database. This mirror should be read-only, and the only thing updating this repo should be the Trac GitHub plugin. A.3 On the Trac server, this plugin must be installed: https://github.com/trac-hacks/trac-github A.4 On the GitHub server, a post-commit web hook must be configured. The workflow will be this: [core committer does push to https://github.com/twisted/twisted] -> [post commit GitHub hook will be called to poke the Trac GitHub plugin] -> [Trac GitHub plugin will update the local git repo on the Trac server] -> [Trac GitHub will parse the git history for new commits and update tickets] I would recommend that steps (1) - (4) be made to work in a staging environment, with a separate GitHub repo, and a separate copy of the Trac database. That way, you can test things out without derailing Twisted developers. When you are confident that this workflow works, then the transition plan will be something like the following. B.1 Send an e-mail to the mailing list and pick one day for the maintenance window. This will warn folks when they should take a holiday from Twisted work. :) B.2 When maintenance is about to begin, send a [HEADSUP] mail saying that repo will be unavailable. B.3 Create Subversion pre-commit hook to disable all commits to Subversion: http://stackoverflow.com/questions/2411122/how-to-freeze-entire-svn-reposit… B.4 Set up steps A.1 - A.4 B.5 Verify that B.4 works. Have someone (Glyph?) do a commit to https://github.com/twisted/twisted, and make sure that Trac works. B.6 Once the Twisted core team are satisified that everything works, send an e-mail to the mailing list that the maintenance window is over, and GitHub is now where the action is! B.7 Update all wiki documentation to change all references to getting code from Subversion, to getting code from GitHub. B.8 Update all systems which used Subversion to use GitHub. For example, buildbots. -- Craig -- Craig

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[Twisted-Python] When's the next release?
by Jonathan Lange 15 Dec '15

15 Dec '15

Hello! I've just landed a fix to #4811, which ought to make it possible to use trial with regular standard library unittests that have expected failures & unexpected successes. I'm very keen to start using that in my code base, and the easiest way for me to do that is for there to be an official release of Twisted. When might one expect the next release to take place? Thanks, jml

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[Twisted-Python] Attaching the release number to a closed/merged ticket
by Adi Roiban 07 Dec '15

07 Dec '15

Hi, I would like to ask you if you think that is a good idea to have the version of Twisted in which the changes associated with a ticket. The use case would be: Someone search the net for something related to Twisted (a bug or some feature) and the land to a Trac ticket. Just by looking at the Trac ticket that person should see if the ticket is still in work, is invalid or changes were made in release YY.NN ------- My proposal for implementing this is: Each release will have a new milestone with the same name called 'next-release'. Once the changes for a ticket were merged the ticket is assigned to the 'next-release' milestone. When release is done, the next-release is renamed to the release name and all previous tickets will be auto-updated. A new milestone called 'next-release' is created. Invalid or duplicate tickets should not have the 'next-relesese' milestone. ----------- Amber commented that using milestones for such a thing is not a good idea and that we should use tags like: landed-in-15.5, landed-for-15.5 ... and keep milestones like Python-3 unchanged. I don't like tags as when a ticket is landed we don't know if next release will be16.0 or 15.6. We can use a 'next-release' tag and when a release is done, check all tickets and update their tag. -------- Please send your suggestions and comments. Thanks! -- Adi Roiban

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[Twisted-Python] incompatible change - need revert before release
by Glyph Lefkowitz 07 Dec '15

07 Dec '15

Tom Prince discovered a regression on https://twistedmatrix.com/trac/ticket/7016#comment:14 <https://twistedmatrix.com/trac/ticket/7016#comment:14> - I think that this was introduced after 15.4, so it needs to be rolled back (or fixed, if someone can get to it before the revert) in 15.5. -glyph

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