Set the consistency level in EXECUTE statements

gocql.go

@@ -63,6 +63,9 @@ const (
 	keyCompression string = "COMPRESSION"
 )
 
+var consistencyLevels = map[string]byte{"any": 0x00, "one": 0x01, "two": 0x02,
+	"three": 0x03, "quorum": 0x04, "all": 0x05, "local_quorum": 0x06, "each_quorum": 0x07}
+
 var rnd = rand.New(rand.NewSource(0))
 
 type drv struct{}
@@ -74,6 +77,7 @@ func (d drv) Open(name string) (driver.Conn, error) {
 type connection struct {
 	c           net.Conn
 	compression string
+	consistency byte
 }
 
 func Open(name string) (*connection, error) {
@@ -91,8 +95,12 @@ func Open(name string) (*connection, error) {
 	}
 
 	version := "3.0.0"
-	keyspace := ""
-	compression := ""
+	var (
+		keyspace    string
+		compression string
+		consistency byte = 0x01
+		ok          bool
+	)
 	for i := 1; i < len(parts); i++ {
 		switch {
 		case parts[i] == "":
@@ -106,13 +114,18 @@ func Open(name string) (*connection, error) {
 					compression)
 			}
 		case strings.HasPrefix(parts[i], "version="):
-			compression = strings.TrimSpace(parts[i][8:])
+			version = strings.TrimSpace(parts[i][8:])
+		case strings.HasPrefix(parts[i], "consistency="):
+			cs := strings.TrimSpace(parts[i][12:])
+			if consistency, ok = consistencyLevels[cs]; !ok {
+				return nil, fmt.Errorf("unknown consistency level %q", cs)
+			}
 		default:
 			return nil, fmt.Errorf("unsupported option %q", parts[i])
 		}
 	}
 
-	cn := &connection{c: c, compression: compression}
+	cn := &connection{c: c, compression: compression, consistency: consistency}
 
 	b := &bytes.Buffer{}
 
@@ -306,6 +319,7 @@ func (st *statement) exec(v []driver.Value) error {
 		copy(body[p+4:], b)
 		p += 4 + len(b)
 	}
+	binary.BigEndian.PutUint16(body[p:], uint16(st.cn.consistency))
 	if err := st.cn.send(opExecute, body); err != nil {
 		return err
 	}