Merge pull request #1 from jrluis/add-peek-function

Add peek function

consulmq.go

@@ -293,6 +293,23 @@ func (mq *MQ) indexPop(queue string) (string, int, error) {
 	return id, len(idx), nil
 }
 
+func (mq *MQ) indexPeek(queue string) (string, int, error) {
+	kv, err := mq.lock(queue)
+	if err != nil {
+		return "", -1, err
+	}
+	defer mq.unlock(kv)
+	idx, _, err := mq.loadIndex(kv)
+	if err != nil {
+		return "", len(idx), err
+	}
+	var id string
+	if len(idx) > 0 {
+		id, idx = idx[0], idx[1:]
+	}
+	return id, len(idx), nil
+}
+
 func (mq *MQ) indexPopLast(queue string) (string, int, error) {
 	kv, err := mq.lock(queue)
 	if err != nil {
@@ -455,6 +472,26 @@ func (mq *MQ) Pop() ([]byte, *QueueObject, error) {
 	return qo.Body, &qo, nil
 }
 
+func (mq *MQ) Peek() ([]byte, *QueueObject, error) {
+	id, _, err := mq.indexPeek("q")
+	if err != nil {
+		return []byte{}, &QueueObject{}, err
+	}
+	obj, _, err := mq.kv.Get(mq.q.QueuePath+id, nil)
+	if err != nil {
+		return []byte{}, &QueueObject{}, err
+	}
+	if obj == nil {
+		return []byte{}, &QueueObject{}, fmt.Errorf("object at head is nil")
+	}
+	var qo QueueObject
+	err = json.Unmarshal(obj.Value, &qo)
+	if err != nil {
+		return []byte{}, &QueueObject{}, err
+	}
+	return qo.Body, &qo, nil
+}
+
 // PopLast removes the last (newest) object in the queue. PopLast returns the message body as bytes and a QueueObject with the object ID,
 // the object's CTime, the TTL deadline, and the message body as bytes.
 func (mq *MQ) PopLast() ([]byte, *QueueObject, error) {

consulmq_test.go

@@ -9,7 +9,6 @@ import (
 	"gopkg.in/yaml.v2"
 )
 
-var TestBytes = []byte("This is a test, this is only a test")
 var config Config
 var mq *MQ
 
@@ -95,6 +94,33 @@ func TestPushPop(t *testing.T) {
 	}
 }
 
+func TestPushPeekQueue(t *testing.T) {
+	testData := []byte(uuid.New().String())
+	err := mq.EmptyQueue()
+	if err != nil {
+		t.Error(err)
+	}
+	_, err = mq.Push(testData)
+	if err != nil {
+		t.Error(err)
+	}
+
+	for i := 0; i < 10; i++ {
+		b, _, err := mq.Peek()
+		if err != nil {
+			t.Error(err)
+		}
+		if string(testData[:]) != string(b[:]) {
+			t.Errorf("Test strings do not match! Had %s got %s", string(testData[:]), string(b[:]))
+		}
+	}
+
+	err = mq.EmptyQueue()
+	if err != nil {
+		t.Error(err)
+	}
+}
+
 func TestPushFirstPopLast(t *testing.T) {
 	testData := []byte(uuid.New().String())
 	err := mq.EmptyQueue()