use 2pc to execute del command in cluster mode

src/cluster/del.go

@@ -0,0 +1,109 @@
+package cluster
+
+import (
+    "github.com/HDT3213/godis/src/interface/redis"
+    "github.com/HDT3213/godis/src/redis/reply"
+    "strconv"
+)
+
+func Del(cluster *Cluster, c redis.Connection, args [][]byte) redis.Reply {
+    if len(args) < 2 {
+        return reply.MakeErrReply("ERR wrong number of arguments for 'del' command")
+    }
+    keys := make([]string, len(args)-1)
+    for i := 1; i < len(args); i++ {
+        keys[i-1] = string(args[i])
+    }
+    groupMap := cluster.groupBy(keys)
+    if len(groupMap) == 1 { // do fast
+        for peer, group := range groupMap { // only one group
+            return cluster.Relay(peer, c, makeArgs("DEL", group...))
+        }
+    }
+    // prepare
+    var errReply redis.Reply
+    txId := cluster.idGenerator.NextId()
+    rollback := false
+    for peer, group := range groupMap {
+        args := []string{strconv.FormatInt(txId, 10)}
+        args = append(args, group...)
+        var ret redis.Reply
+        if peer == cluster.self {
+            ret = PrepareDel(cluster, c, makeArgs("PrepareDel", args...))
+        } else {
+            ret = cluster.Relay(peer, c, makeArgs("PrepareDel", args...))
+        }
+        if reply.IsErrorReply(ret) {
+            errReply = ret
+            rollback = true
+            break
+        }
+    }
+    if rollback {
+        // rollback
+        for peer := range groupMap {
+            cluster.Relay(peer, c, makeArgs("rollback", strconv.FormatInt(txId, 10)))
+        }
+    } else {
+        // commit
+        rollback = false
+        for peer := range groupMap {
+            var ret redis.Reply
+            if peer == cluster.self {
+                ret = Commit(cluster, c, makeArgs("commit", strconv.FormatInt(txId, 10)))
+            } else {
+                ret = cluster.Relay(peer, c, makeArgs("commit", strconv.FormatInt(txId, 10)))
+            }
+            if reply.IsErrorReply(ret) {
+                errReply = ret
+                rollback = true
+                break
+            }
+        }
+        if rollback {
+            for peer := range groupMap {
+                cluster.Relay(peer, c, makeArgs("rollback", strconv.FormatInt(txId, 10)))
+            }
+        }
+    }
+    if !rollback {
+        return reply.MakeIntReply(int64(len(keys)))
+    }
+    return errReply
+}
+
+// args: PrepareDel id keys...
+func PrepareDel(cluster *Cluster, c redis.Connection, args [][]byte) redis.Reply {
+    if len(args) < 3 {
+        return reply.MakeErrReply("ERR wrong number of arguments for 'preparedel' command")
+    }
+    txId := string(args[1])
+    keys := make([]string, 0, len(args)-2)
+    for i := 2; i < len(args); i++ {
+        arg := args[i]
+        keys = append(keys, string(arg))
+    }
+    txArgs := makeArgs("DEL", keys...) // actual args for cluster.db
+    tx := NewTransaction(cluster, c, txId, txArgs, keys)
+    cluster.transactions.Put(txId, tx)
+    err := tx.prepare()
+    if err != nil {
+        return reply.MakeErrReply(err.Error())
+    }
+    return &reply.OkReply{}
+}
+
+// invoker should provide lock
+func CommitDel(cluster *Cluster, c redis.Connection, tx *Transaction) redis.Reply {
+    keys := make([]string, len(tx.args))
+    for i, v := range tx.args {
+        keys[i] = string(v)
+    }
+    keys = keys[1:]
+
+    deleted := cluster.db.Removes(keys...)
+    if deleted > 0 {
+        cluster.db.AddAof(reply.MakeMultiBulkReply(tx.args))
+    }
+    return &reply.OkReply{}
+}