[Twisted-web] Listening on 2 addresses

[Tom Most]

Hi Axel,

makeService() returns an IService. twisted.internet.application.MultiService[1] is an IService that composes other services (it's an IServiceCollection). The implementation would be something like:

def makeService(self, options):
    ipv4 = internet.TCPServer(int(options['port'], meteo_factory, interface=options['ipv4_address'])
    ipv6 = internet.TCPServer(int(options['port'], meteo_factory, interface=options['ipv6_address'])
    root = MultiService()
    ipv4.setServiceParent(root)
    ipv6.setServiceParent(root)
    return root

You might prefer StreamServerEndpointService[2] to TCPServer. String endpoint descriptions[3] are pretty convenient for CLI use.

[1]: https://twistedmatrix.com/documents/current/api/twisted.application.service.MultiService.html
[2]: https://twistedmatrix.com/documents/current/api/twisted.application.internet.StreamServerEndpointService.html
[3]: https://twistedmatrix.com/documents/current/api/twisted.internet.endpoints.html#serverFromString

-- 
  Tom Most
  twm at freecog.net

On Fri, Mar 29, 2019, at 11:39 AM, Axel Rau wrote:
> I have a simple web application with the plugin below.
> It works fine with IPv4 or IPv6. The host has 2 addresses
> (IPv4 + IPv6 = dual stack).
> How can I extend the plugin to let my server listen on both
> addresses?
> 
> Please advice,
> Axel
> 
> PS: The plugin:
> 
> from zope.interface import implementer
> 
> from twisted.application.service import IServiceMaker
> from twisted.application import internet
> from twisted.plugin import IPlugin
> from twisted.python import usage
> 
> from meteo import meteo_factory
> 
> class Options(usage.Options):
> 	optParameters = [	['port', 'p', 80, 'The port number to listen on.'],
> 						['ipv4_address', '4', None, 'The IPv4 address to listen on.'],
> 						['ipv6_address', '6', None, 'The IPv6 address to listen on.'],
> 						['host', 'l', None, 'The hostname where to listen at']]
> 
> @implementer(IServiceMaker, IPlugin)
> class MeteoServiceMaker(object):
> 	tapname = 'meteo'
> 	description = 'A web application for the meteo package'
> 	options = Options
> 	
> 	def makeService(self, options):
> 		"""
> 		Constructs a TCP server from a factory defined in meteo.py
> 		"""
> 		return internet.TCPServer(	int(options['port']), 
>                                     meteo_factory,
>                                     interface=options['ipv6_address'])			
> 
> serviceMaker = MeteoServiceMaker()
> 
> ---
> PGP-Key:29E99DD6  ☀  computing @ chaos claudius