basic cluster mode

src/cluster/cluster.go

@@ -0,0 +1,92 @@
+package cluster
+
+import (
+    "fmt"
+    "github.com/HDT3213/godis/src/config"
+    "github.com/HDT3213/godis/src/db"
+    "github.com/HDT3213/godis/src/interface/redis"
+    "github.com/HDT3213/godis/src/lib/consistenthash"
+    "github.com/HDT3213/godis/src/lib/logger"
+    "github.com/HDT3213/godis/src/redis/client"
+    "github.com/HDT3213/godis/src/redis/reply"
+    "runtime/debug"
+    "strings"
+)
+
+type Cluster struct {
+    self string
+
+    db         *db.DB
+    peerPicker *consistenthash.Map
+    peers      map[string]*client.Client
+}
+
+const (
+    replicas = 4
+)
+
+func MakeCluster() *Cluster {
+    cluster := &Cluster{
+        self: config.Properties.Self,
+
+        db:         db.MakeDB(),
+        peerPicker: consistenthash.New(replicas, nil),
+        peers:      make(map[string]*client.Client),
+    }
+    if config.Properties.Peers != nil && len(config.Properties.Peers) > 0 {
+        cluster.peerPicker.Add(config.Properties.Peers...)
+    }
+    return cluster
+}
+
+// args contains all
+type CmdFunc func(cluster *Cluster, c redis.Client, args [][]byte) redis.Reply
+
+func (cluster *Cluster) Close() {
+    cluster.db.Close()
+}
+
+var router = MakeRouter()
+
+func (cluster *Cluster) Exec(c redis.Client, args [][]byte) (result redis.Reply) {
+    defer func() {
+        if err := recover(); err != nil {
+            logger.Warn(fmt.Sprintf("error occurs: %v\n%s", err, string(debug.Stack())))
+            result = &reply.UnknownErrReply{}
+        }
+    }()
+
+    cmd := strings.ToLower(string(args[0]))
+    cmdFunc, ok := router[cmd]
+    if !ok {
+        return reply.MakeErrReply("ERR unknown command '" + cmd + "'")
+    }
+    result = cmdFunc(cluster, c, args)
+    return
+}
+
+// relay command to peer
+func (cluster *Cluster) Relay(key string, c redis.Client, args [][]byte) redis.Reply {
+    peer := cluster.peerPicker.Get(key)
+    if peer == cluster.self {
+        // to self db
+        return cluster.db.Exec(c, args)
+    } else {
+        peerClient, ok := cluster.peers[peer]
+        // lazy init
+        if !ok {
+            var err error
+            peerClient, err = client.MakeClient(peer)
+            if err != nil {
+                return reply.MakeErrReply(err.Error())
+            }
+            peerClient.Start()
+            cluster.peers[peer] = peerClient
+        }
+        return peerClient.Send(args)
+    }
+}
+
+func (cluster *Cluster) AfterClientClose(c redis.Client) {
+
+}