Move node related stuff to node.go

The cornerstone for exchanging data is the node
structure and associated metadata. Moving it to a
separate file (maybe later a separate module) will help
decoupling.

cluster.go

@@ -1,10 +1,8 @@
 package main
 
 import (
-	"bytes"
 	"crypto/rand"
 	"encoding/base64"
-	"encoding/gob"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -98,37 +96,6 @@ func (c *cluster) GetBroadcasts(overhead, limit int) [][]byte { return nil }
 func (c *cluster) LocalState(join bool) []byte                { return nil }
 func (c *cluster) MergeRemoteState(buf []byte, join bool)     {}
 
-type nodeMeta struct {
-	OverlayAddr net.IPNet
-	PubKey      string
-}
-
-func (c *cluster) NodeMeta(limit int) []byte {
-	buf := &bytes.Buffer{}
-	if err := gob.NewEncoder(buf).Encode(nodeMeta{
-		OverlayAddr: c.wg.OverlayAddr,
-		PubKey:      c.wg.PubKey.String(),
-	}); err != nil {
-		logrus.Errorf("could not encode local state: %s", err)
-		return nil
-	}
-	if buf.Len() > limit {
-		logrus.Errorf("could not fit node metadata into %d bytes", limit)
-		return nil
-	}
-	return buf.Bytes()
-}
-
-func decodeNodeMeta(b []byte) (nodeMeta, error) {
-	// TODO: we blindly trust the info we get from the peers; We should be more defensive to limit the damage a leaked
-	// PSK can cause.
-	nm := nodeMeta{}
-	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&nm); err != nil {
-		return nm, errors.Wrap(err, "could not decode node meta")
-	}
-	return nm, nil
-}
-
 func (c *cluster) join(addrs []string) error {
 	if len(addrs) == 0 {
 		for _, n := range c.state.Nodes {
@@ -197,16 +164,6 @@ func (c *cluster) members() (<-chan []node, <-chan error) {
 	return changes, errc
 }
 
-type node struct {
-	Name string
-	Addr net.IP
-	nodeMeta
-}
-
-func (n *node) String() string {
-	return n.Addr.String()
-}
-
 func computeClusterKey(state *ClusterState, clusterKey []byte) ([]byte, error) {
 	if len(clusterKey) == 0 {
 		clusterKey = state.ClusterKey

node.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"bytes"
+	"encoding/gob"
+	"net"
+
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+// nodeMeta holds metadata sent over the cluster
+type nodeMeta struct {
+	OverlayAddr net.IPNet
+	PubKey      string
+}
+
+// Node holds the memberlist node structure
+type node struct {
+	Name string
+	Addr net.IP
+	nodeMeta
+}
+
+func (n *node) String() string {
+	return n.Addr.String()
+}
+
+func (c *cluster) NodeMeta(limit int) []byte {
+	buf := &bytes.Buffer{}
+	if err := gob.NewEncoder(buf).Encode(nodeMeta{
+		OverlayAddr: c.wg.OverlayAddr,
+		PubKey:      c.wg.PubKey.String(),
+	}); err != nil {
+		logrus.Errorf("could not encode local state: %s", err)
+		return nil
+	}
+	if buf.Len() > limit {
+		logrus.Errorf("could not fit node metadata into %d bytes", limit)
+		return nil
+	}
+	return buf.Bytes()
+}
+
+func decodeNodeMeta(b []byte) (nodeMeta, error) {
+	// TODO: we blindly trust the info we get from the peers; We should be more defensive to limit the damage a leaked
+	// PSK can cause.
+	nm := nodeMeta{}
+	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&nm); err != nil {
+		return nm, errors.Wrap(err, "could not decode node meta")
+	}
+	return nm, nil
+}