Merge pull request #14 from glycerine/fence_len

length option to FENCE, to support batch updates and dedup

machine/server.go

@@ -52,10 +52,22 @@ func (m *Machine) doDbsize(a finn.Applier, conn redcon.Conn, cmd redcon.Command,
 }
 
 func (m *Machine) doFence(a finn.Applier, conn redcon.Conn, cmd redcon.Command, tx *buntdb.Tx) (interface{}, error) {
-	// FENCE token
-	if len(cmd.Args) != 2 {
+	// FENCE token {optional length}
+	narg := len(cmd.Args)
+	if narg != 2 && narg != 3 {
 		return nil, finn.ErrWrongNumberOfArguments
 	}
+	var incr uint64 = 1
+	if narg == 3 {
+		var err error
+		incr, err = strconv.ParseUint(string(cmd.Args[2]), 10, 64)
+		if err != nil {
+			return nil, err
+		}
+		if incr < 1 {
+			return nil, fmt.Errorf("length argument to FENCE must be > 0")
+		}
+	}
 	key := sdbMetaPrefix + "fence:" + string(cmd.Args[1])
 	return m.writeDoApply(a, conn, cmd, tx, func(tx *buntdb.Tx) (interface{}, error) {
 		var n uint64
@@ -70,7 +82,7 @@ func (m *Machine) doFence(a finn.Applier, conn redcon.Conn, cmd redcon.Command,
 				return nil, err
 			}
 		}
-		n++
+		n += incr
 		val = strconv.FormatUint(n, 10)
 		_, _, err = tx.Set(key, val, nil)
 		if err != nil {

machine/transactions_test.go

@@ -163,7 +163,7 @@ func transactions_GET_test(mc *mockCluster) error {
 }
 
 func transactions_FENCE_test(mc *mockCluster) error {
-	return mc.DoBatch([][]interface{}{
+	err := mc.DoBatch([][]interface{}{
 		{"FENCEGET", "mytoken1"}, {"0"},
 		{"FENCEGET", "mytoken2"}, {"0"},
 		{"FENCE", "mytoken1"}, {"1"},
@@ -180,7 +180,10 @@ func transactions_FENCE_test(mc *mockCluster) error {
 		{"FENCE", "mytoken2"}, {"5"},
 		{"FENCEGET", "mytoken2"}, {"5"},
 	})
-	return mc.DoBatch([][]interface{}{
+	if err != nil {
+		return err
+	}
+	err = mc.DoBatch([][]interface{}{
 		{"FENCEGET", "mytoken1"}, {"5"},
 		{"FENCEGET", "mytoken2"}, {"5"},
 		{"FENCE", "mytoken1"}, {"6"},
@@ -196,4 +199,17 @@ func transactions_FENCE_test(mc *mockCluster) error {
 		{"FENCE", "mytoken2"}, {"9"},
 		{"FENCE", "mytoken2"}, {"10"},
 	})
+	if err != nil {
+		return err
+	}
+	// check: FENCE token length
+	err = mc.DoBatch([][]interface{}{
+		{"FENCEGET", "mytoken1"}, {"10"},
+		{"FENCEGET", "mytoken2"}, {"10"},
+		{"FENCE", "mytoken1", "20"}, {"30"},
+		{"FENCE", "mytoken2", "5"}, {"15"},
+		{"FENCEGET", "mytoken1"}, {"30"},
+		{"FENCEGET", "mytoken2"}, {"15"},
+	})
+	return err
 }