Add RAFT stuff

MyRaft/follower.py

@@ -0,0 +1,39 @@
+import MyRaft.state as state
+import MyRaft.candidate as candidate
+import MyRaft.raft_pb2 as raft_pb2
+
+class Follower(state.State):
+    def __init__(self, context):
+        state.State.__init__(self, context)
+        self._context.set_timeout(self._context._min_timout, self._context._vary_timeout)
+
+    def heartbeat_elapsed(self):
+        print("Becoming a candidate")
+        self._context.set_state(candidate.Candidate(self._context))
+
+    def rcv_AppendEntries(self, request):
+        """Called when an append entries message is received"""
+
+        self._context.set_timeout(self._context._min_timout, self._context._vary_timeout)
+
+    def rcv_RequestVote(self, request):
+        print("Received a vote request")
+        # Ignoring log for now.
+        if request.term < self._context.currentTerm:
+            print("They're term is worse than ours.")
+            # If our current term is already the same, then we must have voted already.
+            return raft_pb2.RequestVoteResponse(term = self._context.currentTerm, voteGranted = False)
+        elif request.term == self._context.currentTerm and self._context.votedFor is not None:
+            return raft_pb2.RequestVoteResponse(term = self._context.currentTerm, voteGranted = False)
+        else:
+            print("We'll be voting for them!")
+            # We vote yes, so reset our timeout.
+            self._context.set_timeout(self._context._min_timout, self._context._vary_timeout)
+            self._context.currentTerm = request.term
+            print("setting candidate id")
+            self._context.votedFor = request.candidateId
+            print("Returning result.")
+            return raft_pb2.RequestVoteResponse(term = self._context.currentTerm, 
+                                                voteGranted = True,
+                                                voterId = self._context._id)
+