Refactors fromAny and fromIterator to make the code DRY

mino/minogrpc/README.md

@@ -2,5 +2,4 @@
 
 - [ ] Merge OverlayMsg and Envelope
 - [ ] Check the `<-ctx.Done()` in overlay.go
-- [ ] Test traffic.go
-- [ ] Refactor the two function fromAny and fromItarator in routing
+- [ ] Test traffic.go

mino/minogrpc/routing/message.proto

@@ -5,5 +5,6 @@ package routing;
 import "google/protobuf/any.proto";
 
 message TreeRoutingProto {
+    // Should be the MarshalText representation of each addr
     repeated bytes addrs = 1;
 }

mino/minogrpc/routing/routing.go

@@ -111,56 +111,12 @@ func (t TreeRoutingFactory) FromIterator(iterator mino.AddressIterator) (Routing
 			"the iterator")
 	}
 
-	sort.Stable(&addrsBuf)
-
-	// We will use the hash of the addresses to set the random seed.
-	hash := sha256.New()
-	for _, addr := range addrsBuf {
-		_, err := hash.Write(addr)
-		if err != nil {
-			fabric.Logger.Fatal().Msgf("failed to write hash: %v", err)
-		}
-	}
-
-	seed := binary.LittleEndian.Uint64(hash.Sum(nil))
-
-	// We shuffle the list of addresses, which will then be used to create the
-	// network tree.
-	rand.Seed(int64(seed))
-	rand.Shuffle(len(addrsBuf), func(i, j int) {
-		addrsBuf[i], addrsBuf[j] = addrsBuf[j], addrsBuf[i]
-	})
-
-	addrs := make([]mino.Address, len(addrsBuf))
-	for i, addrBuf := range addrsBuf {
-		addrs[i] = t.addrFactory.FromText(addrBuf)
+	routing, err := t.fromAddrBuf(addrsBuf)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to build from addrsBuf: %v", err)
 	}
 
-	// maximum number of direct connections each node can have. It is comupted
-	// from the treeHeight and the total number of nodes. There are the
-	// following relations:
-	//
-	// N: total number of nodes
-	// D: number of direct connections wanted for each node
-	// H: height of the network tree
-	//
-	// N = D^H
-	// D = sqrt[H](N)
-	// H = log_D N
-	d := int(math.Ceil(math.Pow(float64(len(addrs)), 1.0/float64(t.height))))
-
-	tree := buildTree(t.rootAddr, addrs, d, -1)
-
-	routingNodes := make(map[string]*treeNode)
-	routingNodes[t.rootAddr.String()] = tree
-	tree.ForEach(func(n *treeNode) {
-		routingNodes[n.Addr.String()] = n
-	})
-
-	return &TreeRouting{
-		routingNodes: routingNodes,
-		root:         tree,
-	}, nil
+	return routing, nil
 }
 
 // FromAny creates the network tree in a deterministic manner based on
@@ -173,25 +129,15 @@ func (t TreeRoutingFactory) FromAny(m *any.Any) (Routing, error) {
 		return nil, xerrors.Errorf("failed to unmarshal routing message: %v", err)
 	}
 
-	if len(msg.Addrs) == 0 {
-		return nil, xerrors.Errorf("there should be at least one address")
-	}
-
-	addrs := make([]mino.Address, len(msg.Addrs))
-	for i, addrBuf := range msg.Addrs {
-		addr := t.addrFactory.FromText(addrBuf)
-		addrs[i] = addr
+	routing, err := t.fromAddrBuf(msg.Addrs)
+	if err != nil {
+		return nil, xerrors.Errorf("failed to build from addrsBuf: %v", err)
 	}
 
-	addrsBuf := make(addrsBuf, len(addrs))
-	for i, addr := range addrs {
-		addrBuf, err := addr.MarshalText()
-		if err != nil {
-			return nil, xerrors.Errorf("failed to marshal addr '%s': %v", addr, err)
-		}
+	return routing, nil
+}
 
-		addrsBuf[i] = addrBuf
-	}
+func (t TreeRoutingFactory) fromAddrBuf(addrsBuf addrsBuf) (Routing, error) {
 
 	sort.Stable(&addrsBuf)
 
@@ -213,11 +159,12 @@ func (t TreeRoutingFactory) FromAny(m *any.Any) (Routing, error) {
 		addrsBuf[i], addrsBuf[j] = addrsBuf[j], addrsBuf[i]
 	})
 
+	addrs := make([]mino.Address, len(addrsBuf))
 	for i, addrBuf := range addrsBuf {
 		addrs[i] = t.addrFactory.FromText(addrBuf)
 	}
 
-	// maximum number of direct connections each node can have. It is computed
+	// maximum number of direct connections each node can have. It is comupted
 	// from the treeHeight and the total number of nodes. There are the
 	// following relations:
 	//