server: add node id

cli/server/command.go

@@ -81,6 +81,16 @@ connections to upstream listeners, announcing to the cluster the node is
 leaving...`,
 	)
 
+	cmd.Flags().StringVar(
+		&conf.Cluster.NodeID,
+		"cluster.node-id",
+		"",
+		`
+A unique identifier for the node in the cluster.
+
+By default a random ID will be generated for the node.`,
+	)
+
 	cmd.Flags().StringSliceVar(
 		&conf.Cluster.Members,
 		"cluster.members",
@@ -168,6 +178,10 @@ Such as you can enable 'gossip' logs with '--log.subsystems gossip'.`,
 			os.Exit(1)
 		}
 
+		if conf.Cluster.NodeID == "" {
+			conf.Cluster.NodeID = netmap.GenerateNodeID()
+		}
+
 		run(&conf, logger)
 	}
 

server/config/config.go

@@ -16,6 +16,8 @@ type ServerConfig struct {
 }
 
 type ClusterConfig struct {
+	NodeID string `json:"node_id"`
+
 	Members []string `json:"members"`
 }
 

server/netmap/node.go

@@ -1,5 +1,14 @@
 package netmap
 
+import (
+	"crypto/rand"
+	"math/big"
+)
+
+var (
+	alphaNumericChars = []byte("abcdefghijklmnopqrstuvwxyz1234567890")
+)
+
 // Node represents the known state about a node in the cluster.
 type Node struct {
 	// ID is a unique identifier for the node in the cluster.
@@ -15,3 +24,17 @@ type Node struct {
 	// active endpoint ID to the number of listeners for that endpoint.
 	Endpoints map[string]int
 }
+
+func GenerateNodeID() string {
+	b := make([]byte, 10)
+	for i := range b {
+		n, err := rand.Int(rand.Reader, big.NewInt(int64(len(alphaNumericChars))))
+		if err != nil {
+			// We don't expect to ever get an error so panic rather than try to
+			// handle.
+			panic("failed to generate random number: " + err.Error())
+		}
+		b[i] = alphaNumericChars[n.Int64()]
+	}
+	return string(b)
+}