coder and start transaction

antidoteclient.go

@@ -6,9 +6,6 @@ import (
 	"fmt"
 	"math/rand"
 	"time"
-	"io"
-	"github.com/golang/protobuf/proto"
-	"encoding/binary"
 )
 
 const INITIAL_POOL_SIZE = 1
@@ -71,21 +68,7 @@ type Connection struct {
 
 type InteractiveTransaction struct {
 	TxID []byte
-	con Connection
-}
-
-func (op *ApbStartTransaction) encode(writer io.Writer) (err error) {
-	msg, err := proto.Marshal(op)
-	if err != nil {
-		return
-	}
-	msgsize := len(msg)
-	buf := make([]byte, 5)
-	binary.BigEndian.PutUint32(buf[0:4], uint32(msgsize))
-	buf[5] = 119
-	writer.Write(buf)
-	writer.Write(msg)
-	return nil
+	con *Connection
 }
 
 func (client *Client) StartTransaction() (tx *InteractiveTransaction, err error) {
@@ -96,6 +79,19 @@ func (client *Client) StartTransaction() (tx *InteractiveTransaction, err error)
 	apbtxn := &ApbStartTransaction{
 		Properties: &ApbTxnProperties{},
 	}
-	apbtxn.encode(con)
-	// TODO get response, extract txid, return object
+	err = apbtxn.encode(con)
+	if err != nil {
+		return
+	}
+
+	apbtxnresp, err := decodeStartTransactionResp(con)
+	if err != nil {
+		return
+	}
+	txndesc := apbtxnresp.TransactionDescriptor
+	tx = &InteractiveTransaction{
+		con: con,
+		TxID: txndesc,
+	}
+	return
 }

coder.go

+package antidoteclient
+
+import (
+    "encoding/binary"
+    "io"
+    "github.com/golang/protobuf/proto"
+    "fmt"
+)
+
+func readMsgRaw(reader io.Reader) (data []byte, err error) {
+    sizeB := make([]byte, 4)
+    var count uint32
+    // read the size of the message
+    count = 0
+    for count != 4 {
+        n, err := reader.Read(sizeB[count:])
+        if err != nil {
+            return
+        }
+        count += uint32(n)
+    }
+    sizeI := binary.BigEndian.Uint32(sizeB)
+    data = make([]byte, sizeI)
+    // read data
+    count = 0
+    for count != sizeI {
+        n, err := reader.Read(data[count:])
+        if err != nil {
+            data = nil
+            return
+        }
+        count += uint32(n)
+    }
+    return
+}
+
+func (op *ApbStartTransaction) encode(writer io.Writer) (err error) {
+    msg, err := proto.Marshal(op)
+    if err != nil {
+        return
+    }
+    msgsize := len(msg)
+    buf := make([]byte, 5)
+    binary.BigEndian.PutUint32(buf[0:4], uint32(msgsize))
+    buf[5] = 119
+    writer.Write(buf)
+    writer.Write(msg)
+    return nil
+}
+
+func decodeStartTransactionResp(reader io.Reader) (op *ApbStartTransactionResp, err error) {
+    data, err := readMsgRaw(reader)
+    if err != nil {
+        return
+    }
+    switch data[0] {
+    case 0:
+        // error
+        err = decodeError(data[1:])
+        return
+    case 124:
+        // transaction response
+        resp := &ApbStartTransactionResp{}
+        err = proto.Unmarshal(data[1:], resp)
+        if err != nil {
+            return
+        }
+        op = resp
+        return
+    }
+    err = fmt.Errorf("invalid message code: %d", data[0])
+    return
+}
+
+func decodeError(data []byte) (err error) {
+    resp := &ApbErrorResp{}
+    err = proto.Unmarshal(data, resp)
+    if err != nil {
+        return
+    }
+    err = fmt.Errorf("antidote error code %d, %s", resp.Errcode, string(resp.Errmsg))
+    return
+}