dht_node: split network start and join procedures

In order to attempt to join the DHT several times
(i.e. when the first attempt has failed) we need to
split the components initialization from the real
joining operation.

Create node.startNetwork() to initialize the node
and keep the rest in node.joinNetwork()

Signed-off-by: Antonio Quartulli <antonio@mandelbit.com>

lbrynet/core/Session.py

@@ -247,12 +247,11 @@ class Session(object):
         d.addErrback(upnp_failed)
         return d
 
-    def _setup_dht(self):
-
+    # the callback, if any, will be invoked once the joining procedure
+    # has terminated
+    def join_dht(self, cb=None):
         from twisted.internet import reactor
 
-        log.info("Starting DHT")
-
         def join_resolved_addresses(result):
             addresses = []
             for success, value in result:
@@ -260,10 +259,11 @@ class Session(object):
                     addresses.append(value)
             return addresses
 
-        def start_dht(join_network_result):
-            self.peer_finder.run_manage_loop()
-            self.hash_announcer.run_manage_loop()
-            return True
+        @defer.inlineCallbacks
+        def join_network(knownNodes):
+            log.debug("join DHT using known nodes: " + str(knownNodes))
+            result = yield self.dht_node.joinNetwork(knownNodes)
+            defer.returnValue(result)
 
         ds = []
         for host, port in self.known_dht_nodes:
@@ -271,6 +271,22 @@ class Session(object):
             d.addCallback(lambda h: (h, port))  # match host to port
             ds.append(d)
 
+        dl = defer.DeferredList(ds)
+        dl.addCallback(join_resolved_addresses)
+        dl.addCallback(join_network)
+        if cb:
+            dl.addCallback(cb)
+
+        return dl
+
+    def _setup_dht(self):
+        log.info("Starting DHT")
+
+        def start_dht(join_network_result):
+            self.peer_finder.run_manage_loop()
+            self.hash_announcer.run_manage_loop()
+            return True
+
         self.dht_node = self.dht_node_class(
             udpPort=self.dht_node_port,
             node_id=self.node_id,
@@ -281,11 +297,10 @@ class Session(object):
         if self.hash_announcer is None:
             self.hash_announcer = DHTHashAnnouncer(self.dht_node, self.peer_port)
 
-        dl = defer.DeferredList(ds)
-        dl.addCallback(join_resolved_addresses)
-        dl.addCallback(self.dht_node.joinNetwork)
-        dl.addCallback(start_dht)
-        return dl
+        self.dht_node.startNetwork()
+
+        # pass start_dht() as callback to start the remaining components after joining the DHT
+        return self.join_dht(start_dht)
 
     def _setup_other_components(self):
         log.debug("Setting up the rest of the components")

lbrynet/dht/node.py

@@ -132,17 +132,12 @@ class Node(object):
             self._listeningPort.stopListening()
         self.hash_watcher.stop()
 
-    @defer.inlineCallbacks
-    def joinNetwork(self, knownNodeAddresses=None):
-        """ Causes the Node to join the Kademlia network; normally, this
-        should be called before any other DHT operations.
-
-        @param knownNodeAddresses: A sequence of tuples containing IP address
-                                   information for existing nodes on the
-                                   Kademlia network, in the format:
-                                   C{(<ip address>, (udp port>)}
-        @type knownNodeAddresses: tuple
+    def startNetwork(self):
+        """ Causes the Node to start all the underlying components needed for the DHT
+        to work. This should be called before any other DHT operations.
         """
+        log.info("Starting DHT underlying components")
+
         # Prepare the underlying Kademlia protocol
         if self.port is not None:
             try:
@@ -151,6 +146,29 @@ class Node(object):
                 import traceback
                 log.error("Couldn't bind to port %d. %s", self.port, traceback.format_exc())
                 raise ValueError("%s lbrynet may already be running." % str(e))
+
+        # Start the token looping call
+        self.change_token_lc.start(constants.tokenSecretChangeInterval)
+        #        #TODO: Refresh all k-buckets further away than this node's closest neighbour
+        # Start refreshing k-buckets periodically, if necessary
+        self.next_refresh_call = reactor.callLater(constants.checkRefreshInterval,
+                                                   self._refreshNode)
+        self.hash_watcher.tick()
+
+    @defer.inlineCallbacks
+    def joinNetwork(self, knownNodeAddresses=None):
+        """ Causes the Node to attempt to join the DHT network by contacting the
+        known DHT nodes. This can be called multiple times if the previous attempt
+        has failed or if the Node has lost all the contacts.
+
+        @param knownNodeAddresses: A sequence of tuples containing IP address
+                                   information for existing nodes on the
+                                   Kademlia network, in the format:
+                                   C{(<ip address>, (udp port>)}
+        @type knownNodeAddresses: tuple
+        """
+        log.info("Attempting to join the DHT network")
+
         # IGNORE:E1101
         # Create temporary contact information for the list of addresses of known nodes
         if knownNodeAddresses != None:
@@ -161,18 +179,11 @@ class Node(object):
         else:
             bootstrapContacts = None
 
-        # Start the token looping call
-        self.change_token_lc.start(constants.tokenSecretChangeInterval)
-
         # Initiate the Kademlia joining sequence - perform a search for this node's own ID
         self._joinDeferred = self._iterativeFind(self.node_id, bootstrapContacts)
-        #        #TODO: Refresh all k-buckets further away than this node's closest neighbour
-        # Start refreshing k-buckets periodically, if necessary
-        self.next_refresh_call = reactor.callLater(constants.checkRefreshInterval,
-                                                   self._refreshNode)
 
-        self.hash_watcher.tick()
-        yield self._joinDeferred
+        result = yield self._joinDeferred
+        defer.returnValue(result)
 
     @property
     def contacts(self):