raft cluster core

cluster/core/utils.go

@@ -0,0 +1,68 @@
+package core
+
+import (
+	"hash/crc32"
+	"strings"
+
+	"github.com/hdt3213/godis/interface/redis"
+	"github.com/hdt3213/godis/redis/protocol"
+)
+
+const SlotCount int = 1024
+
+const getCommittedIndexCommand = "raft.committedindex"
+
+func init() {
+	RegisterCmd(getCommittedIndexCommand, execRaftCommittedIndex)
+}
+
+// relay function relays command to peer or calls cluster.Exec
+func (cluster *Cluster) Relay(peerId string, c redis.Connection, cmdLine [][]byte) redis.Reply {
+	// use a variable to allow injecting stub for testing, see defaultRelayImpl
+	if peerId == cluster.SelfID() {
+		// to self db
+		return cluster.Exec(c, cmdLine)
+	}
+	// peerId is peer.Addr
+	cli, err := cluster.connections.BorrowPeerClient(peerId)
+	if err != nil {
+		return protocol.MakeErrReply(err.Error())
+	}
+	defer func() {
+		_ = cluster.connections.ReturnPeerClient(cli)
+	}()
+	return cli.Send(cmdLine)
+}
+
+// GetPartitionKey extract hashtag
+func GetPartitionKey(key string) string {
+	beg := strings.Index(key, "{")
+	if beg == -1 {
+		return key
+	}
+	end := strings.Index(key, "}")
+	if end == -1 || end == beg+1 {
+		return key
+	}
+	return key[beg+1 : end]
+}
+
+func GetSlot(key string) uint32 {
+	partitionKey := GetPartitionKey(key)
+	return crc32.ChecksumIEEE([]byte(partitionKey)) % uint32(SlotCount)
+}
+
+// pickNode returns the node id hosting the given slot.
+// If the slot is migrating, return the node which is exporting the slot
+func (cluster *Cluster) PickNode(slotID uint32) string {
+	return cluster.raftNode.FSM.PickNode(slotID)
+}
+
+// format: raft.committedindex
+func execRaftCommittedIndex(cluster *Cluster, c redis.Connection, cmdLine CmdLine) redis.Reply {
+	index, err := cluster.raftNode.CommittedIndex()
+	if err != nil {
+		return protocol.MakeErrReply(err.Error())
+	}
+	return protocol.MakeIntReply(int64(index))
+}