Added new process-pool runner based on AMPoule (integrated into Evennia).

This allows e.g. utils.utils.run_async to offload long-running functions
to a completely different subprocess entirely, offering real parallelism.

Implementation is still experimental, notably not all objects can be
transferred safely across the wire; also there is no concept of
updating caches yet - so adding an object from the subprocess side
will not be known in the main thread yet (since caches cannot yet tell
the underlying database has changed).

src/utils/ampoule/test/test_proxy.py

@@ -0,0 +1,49 @@
+from twisted.internet import defer, reactor
+from twisted.internet.protocol import ClientFactory
+from twisted.trial import unittest
+from twisted.protocols import amp
+
+from src.utils.ampoule import service, child, pool, main
+from src.utils.ampoule.commands import Echo
+
+class ClientAMP(amp.AMP):
+    factory = None
+    def connectionMade(self):
+        if self.factory is not None:
+            self.factory.theProto = self
+            if hasattr(self.factory, 'onMade'):
+                self.factory.onMade.callback(None)
+
+class TestAMPProxy(unittest.TestCase):
+    def setUp(self):
+        """
+        Setup the proxy service and the client connection to the proxy
+        service in order to run call through them.
+
+        Inspiration comes from twisted.test.test_amp
+        """
+        self.pp = pool.ProcessPool()
+        self.svc = service.AMPouleService(self.pp, child.AMPChild, 0, "")
+        self.svc.startService()
+        self.proxy_port = self.svc.server.getHost().port
+        self.clientFactory = ClientFactory()
+        self.clientFactory.protocol = ClientAMP
+        d = self.clientFactory.onMade = defer.Deferred()
+        self.clientConn = reactor.connectTCP("127.0.0.1",
+                                self.proxy_port,
+                                self.clientFactory)
+        self.addCleanup(self.clientConn.disconnect)
+        self.addCleanup(self.svc.stopService)
+        def setClient(_):
+            self.client = self.clientFactory.theProto
+        return d.addCallback(setClient)
+
+    def test_forwardCall(self):
+        """
+        Test that a call made from a client is correctly forwarded to
+        the process pool and the result is correctly reported.
+        """
+        DATA = "hello"
+        return self.client.callRemote(Echo, data=DATA).addCallback(
+            self.assertEquals, {'response': DATA}
+        )